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MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS-1963-A

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MICROCOPY RESOLUTION TEST CHART NATIDNAL BUREAU OF STANOAROS-1963-A

COTTONSEED TREATMENT

Technical Bulletin No 1025 bull December 1950

bull

Cottonseed Treatlnent Its Effect on Seedling Enlcrgcnce Seedling Survival Plant Slands

and Yields 1

By Tin CO~IIITTEE O~ COTTON SEEl)LlM~ DISKSES OF TilE COTTON

DISEASE COUNCIL ~

Unitcd States Departmcnt of Agri(lIltllrc Bureau of Pia III Industry Soils and Agricultural Engincering in cooperation with the agricultural experimiddot ment stations of Arkansas Georgia Louisiana Mississippi North Cafo) lina Oklahoma South Carolina Tennessee Texas and Virginia

CONTENTS

Introduction __ 2 Response to seed treatment as inshyfluenced by the characteristics

General summary __ B of the seed lots and environshyReview of literature__ 6 me]l~l conditions (A test) 13 Experimental procedure _ 6 Characteristics of the seed lots IS

Objectives and locations of Fungicides tested and rates of plantings __ 6 application 14

Seedling survival as influencedSelection and preparation of the by the characteristics of theseed 7 seed 14 Plot technique 10 Response to seed treatment as Collection and interpretation of influenced by weather condishy

data 11 tions 28

1 Submitted for publication May 8 1960 ~ In a cooperative undertaking of this scope it would be almost impossible

to acknowled-e all of the agencies and workers who have contributed to the work PersCllnel and facilities for the experimental work were provided by the agricultural experiment stations of the 10 States in which the work was conducted at the locations given in the bulletin and by the U S Cotton Field Stations 1936-42 inclusive Planting seeds were donated by the commereial seed companies the agricultural experiment stations or the U S Cotton Field Stations that originated or maintained each variety Chemical comshypanies that originated or marrieted the chemical seed treatments that were used donated the materials and their research specialists gave freely of their

bull services during the course of the experiments The assistance of these and others whQ have made contrihutions to this work is gratefully acknowledged

1

2 TECHNICAl BULLETIN 1025 U S DEPT OF AGRlCUlTURE

CONTENTS-CONTINUED

Response to seed treatment etc An evaluation of fungicides etc -Con -Con

Effect of seed treatment on Comparative seedling emergence emergence 32 for reginned and delinted seed 65

Effect of seed treatment on the Effect of the legree of lint reshyprogress of seedling emer- moval in reginning on eedshygence 34 ling emergence 68

Seed treatment lind postemcrshy Comparative yield for fuzzygence loss of seedlings 38 reginned and delinted seed 75

Effect of seed treatment Oil nnlll An evaluation of various fungishygtands and on the survival of cides used in the treatments 75plants from thinninl to time of picking 41 Stunds yields and statistical

analyses 83Effect of seed treatment on yiellf 47 Summary of the B test 84

Helative effect of seed tnmtment An evaluation of various fungishyon seedling survival stands cides for the treatment of C(ltshyand yields 50 tonseed (C test) 85

An evaluation of fln~icidcs on Chemicals used 85 fuzzy rc~inned anil delillfed Results in 1939 86seed (B test) 57

Results in 1940 92Objectivelil 57 Comparisons of the charactcr- Results in 1941 102

ist~cs of fuzzy rc~inncd and Results in 1942 106 dehnted seed 57 Summary of rcsults of other tests

C(flllllhfl1ativc sCdmiddotedlil~g cmcrgedllce 1941-48 108 01 uzzy an regmneu see 63

Compallltivc seedlin~ cmclgcncc Literature cited 110 for fuzzy and delinted seed 65 Appendix 115

INTBO()UCTIO~

In recent yea 11 intensive Rtudies have been made of cottonshyseedling diseases with the objective of discovering some means of reducing losses from seedling diseases and thereby increasing seedling emelge~ce and survival Control of these diseases is especially pertinent since it has been demonstrated repeatedly that early planting and a uniform Rtand of plants are essential for proshyfitable yields in areas infested by the boll weevil In view of the inadequate information on cotton-ReemiddotHing diseases especially as to their prevalence and distribution the plant pathologists conshycerned with cotton-seedling diseases in the several cotton-producshying States in 1936 constituted themselves a committee to coordinate studies on the etiology of cotton-seedling diseases and to study the possibility of control by seed treatment This bulletin summarizes the results of field plantings made in 10 States from 1936 to 1942 to evaluate valious seed treatments and also to ascertain the extent to which the rlsponse to seed treatment was correlated with characteristics of each lot of cottonseed

bull bull

bull

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FOREWORD

The Cotton Disease Council composed of Federal and State research pathologists interested in the control of cotton diseases was organized at the meeting of the Southern Agricultural Workshyers at Jackson Miss in February 1936 The Committee on Cotton Seedling Diseases of the Council immediately planned an extensive series of seed-treatment l-tudies The fn~st series was started in Ul spring of 1936 Experiments summarized in this bulletin COl elucted from 1936 to 1942 inclusive represent work of this still shyactive committee Meager parts of the data presented here have been published by individual cooperators who participated in this work

C II Arndt of the South Carolina Agricultural Experiment Station first chairman of the committee started preparing and distributing the seed from a ~iven 10t all treated in the same manner He also stalmiddottell assembling and Rtatistically analyzing the elata Throughout the course of these studies Dr Arndt conshytinued to summarize the data to J1(lp in selecting and preparing the seed lots and to deige uniform planting plans to facilitate interpreting the data Successive chairmen particularly S G Lehman oJ the North Carolina Agricultural Experiment Station and 1) )L Simpson 01 the Lnited States Department of Agriculshyture cooperating with the Tennesee Agricultural Experiment Station han contributed much thought time and energy to the work Other committee chairmen associated for a shorter period of time ith thee tultiiC w(re L E vriles deceased and his uccessor J A Pir ~kard Both were jointly employed by the [jsisslppi -gricultural EXlwriment Station and the 1nited States Departnwnt of Agriculture

Other cOl11mittet nwmbers who have been acti(~ participants in the studies are G E Altntt (College Station Tex) H D Barker (Washington D el L ]f Blank (College Station Tex) K S Chest(r (Stillwater Okla) U R Gore (Experiment Ga) D C Neal (Baton Hogue La) W W Ray (Stillwater Okla) C H Rogers (Temple Tex) A L Smith (Experiment Ga) A J Lillshystrup (CI(msol1 S C) S A Wingclrd (Blacksburg Va) and V IIYOLng CFavetteilleArk) As llotedin the acknowledgshyment pag( 1 many agencie and workers other than those here mentioned have contributed to this cooperative undertaking All who are familiar with trw work however will agree that C H Arndt has clone the Imlk of tIll wO~k including the analyzing and assembling of the data [or publication

H D BA[lKER pIiuriwi lutlhJisl Dilis1 of CaNol Llti OfIf Fiber Crups (wci niSCClilCII

U11I(W Id Plalll idm1Iry So[(s ami AJlj(l(liul(tl BIIJillCCrillJ AyricIlulal [(Isnp(h Aill1lillistratio) bull

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3 COTTONSEED TREATMENT

GENERAl SUMMARY

The increa~es in seedling emergence seedling survival and plant tands that resulted from the treatment of cottonseed with an effective fungicide were greatest for fuzzy seed that were infested by the anthracnaso furgus Colletotrichwm goss1fpii when soil condition~ and temperature were favorable for seedling infection by thiH fungus Large increases were also obtainHt with several lots of fuzzy seed that were infested by Rhizopus nigricnns Treatshyment of lots of fuzzy seed of good viability and not infested by either of the aboe fungi generally resulted in only small increases in seedling emergence and survival even when the percentage of seedling emergence was low Treatment of lots of low viability usually resulted in larger increases than did the treatment of lots of higher iability when thf lots were comparable in other reshyspects The increa-es that resulted from seed treatment regardless of the characteristics of the lot of seed tended to be larger in early plantings in which emergence was orten delayed by cool rainy weather than in later plantings when weather conditions were uStl~llly more favora e for rapid seedling emergence and growth

The more cfrectie fungicides used in these tests did not always increase seedling emergence and prevent damping-off when condishytions were fworable 101 infection of the seedlings by soil-inhabit shying pathogens which indicates that they acted lalgely as seed di~inf(ctlnts rather than as seedling protectants However in ie(ral pladings in which two or more seedling counts were made the treatment of seed lots not infested by C gossypi-i did result in reduced damping-off as well as a lesseuror number of lesions on the hypocotyls of surviving seedlings The instances in which seed treatment failed to increase emergence were more frequent on the hea soil of the Jfississippi Delta than on lighter and better cI ra i ned soils Isolations from diseased seedl i ngs obtained from these plantings showed that bacteria Fl)coiwn lIlollilifornle other fuaria Rhioclollia ()iali an(1 nliOtlS other soil-inhabiting pathogen had inf(cterJ thp seeds and seedlings

pecial tlsts of the ((fect of tJpclting cottonseed with organic I1wrcurial that diffpr(d gnatly in such characteristics as water -olubility and volatility in(icatNj that the cffectieness of this trlatm~~nt lt1 not HSiociatld with a definite physical-chemical property It n shown however that relatively large amounts of CQm para thely Olil tile btl t Iionolu ble mercu rial were less toxic to cotton seedlings a- indicated hy emergence of eed treated with them the1 les olalile and more soluble mercurials Although relathely nonolatilc mercurials efIectiely eliminated Reed-borne pathogens rendts with other chemicals geemed to Rhow that a funshygicide must be olatile to some degree if it is to be an effective chemical for the treatment of fuzzy and Ieginned seed Volatile and nOlwolatile fungicides wer( equally effecthe for the heatment of add-delinted cottons(((1

bull

4 TECHNICAL BULLETIN 1025 U S DEPT OF AGRICUITURE

Seed treatment increased final stands to a much smaller extent than it increased seedling emergence and survival This was bull largely accounted for by the fact that a much heavier rate of seeding was used than was necessary to produce a stand of plants in most plantings Plant-stand counts were made after thinning and again at the time of picking in a number of plantings Losses during this interval averaged slightly less than 10 percent but were occasionally greater than 20 percent Analysis of the data showed no correlation between after-thinning losses and treatshyment or characteristics of the seed Apparently the seed-borne pathogens had no direct relation to the agents that kill cotton plants after the seedling stage

In most plantings seed treatment produced no increases or only small increases in yield This should logically be expected from the generally small differences in residual stand after thinning beshytween the untreated and treated seed However occasional inshycreases in yield as great as 20 percent were obtained and in the A tests of 1936-39 the mean increases for lots infested by C g08~ypii generally ranged from 7 to 12 percent The failure of seed treatment to produce increased yields in every planting does not invalidate the general belief that the treatment of cottonseed is a good practice since the usual small increases and occasional larger increases in yield fully compensate for the expense and inshyconveniences associated with seed treatment

Seed treatment also may be considered good insurance against the low yields usually associated with replanting in seasons when untreated seed will not produce an adequate stand at the usual bull time of planting The results obtained in these plantings have demonstrated that seed treated with an effective fungicide will generally produce a larger and more uniform stand of plants than untreated seed Consequently seed treatment may be used as a means of obtaining an adequate stand of p1ants for optimal yields from a smaller number of seeds

The response to treatment of reginned seed (seed from which part of the linters was removed in a second ginning) was freshyquently different from that of fuzzy seed from the same lot In some instances the emergence of the untreated reginned seed was much greater than that of the untreated fuzzy seed and conseshyquently the response of reginned seed to treatment was much smaller It is presumed that these differences in some manner were associated with a reduction in the amount of infective myceliti and spores of C gossypii during reginning Observations on the temperature of the seed mass during reginning showed that the maximal temperature attained wes not high enough to kill the bull anthracnose fungus

With other lots of seed the emergence of the untreated reginned

bull

seed was about the same or slightly lower than that of the correshysponding untreated fuzzy seed and the seed treatment resulted in comparable increases for both Heavily reginned seed tended to

5 COTTONSEED TREATMENT

bull give a larger response to treatment than less heavily reginned seed Since scarification of the seed coat tended to increase with the amount of lint removed it is likely that the high response of certain lots of reginned seed to treatment was in some manner associated with the scarification of the seed coat in reginning

Treatment of acid-delinted seed with fungicides generally reshysulted in only small increases in seedling emergence although there were large increases in several plantings in which emergence was delayed by cool rainy weather The testae of acid-delinted seed are very slisceptible to invasion by saprophytic fungi and when emergence is delayed such fungi may kill the young seedshylings Although the treatment of acid-delinted seed with a fungishycide usually produced only small increases in seedling emergence treatment appears to be fully justified because of the occasional large increases in emergence

Regardless of the occasional instances in which fuzzy seed tended to emerge more slowly than reginned and delinted seed no superiority in ability to produce stands of plants or yields was shown for reginned delinted or water-graded delinted seed as compared to that of fuzzy seed when these three kinds of seed were treated with an effective fungicide The results of these plantings would indicate that any advantage that one of these types of seed may have in comparison to another must lie in some convenience related to agronomic practice

HEVIEW OF L1TERATFHE

Previollsly published observations dating from those of Atkinshy)on (UU)1 have ascribed damping-off to Rhizoctonia solani Kuehn (36 gt2 61) CollelotrichllnL gossypii South4 (1 15 32) Fll-sariwn vasinfectum Atk (gt6) other fusaria (51 5n Scleroshytililit rolj-sii Sacco (16) Pythiwn ultimum Trow (2) Phymatoshytrichwn omniVOium (Shear) Duggar (53) and Thielaviopsis basicola (Berk) Ferraris (50) It has been supposed that F-U8arshyium moniliorlHe Sheldon also might be the cause of damping-off although there arl no published observations to this effect This funguil however has been definitely shown to invade cotton roots (61) The possibility of seedling infection arising from seed-borne C gossypii was first ciemolutrated by Atkinson (11) and later emphasized by Barre (Vi) and Edg-erton (24) Experiments by Rolfs (55) and by lltaulwetter (27) have shown that Xanthomona4 malvacealuln (E F Sm) Dowson also may be seed-borne F vasshyinfectum has been reported as a seed-borne disease (25 56 60) Many other fungi have been ifiolated from the interior of cottonshyseeds (22) There is still some question however as to whether any of the seed-borne bacteria and fungi except C gossypii and

I Italic numbers in parentheses refer to Literature Cited p 110 I This name is used for the anthracnose fungus in this paper instead of

Glomrella gOllsYJJii (South) Edg becliuse of the unltcrtuinty of the identity of C gOllllllpii with the Glomrrtlilt isoilited by Edgerton (57)bull

6 TECH~ICAL BULBTIN 102 tT S DEPT OF AGRICULTURJltJ

possibly X malvace(poundrum and F moniliforme are an economically important cause of the damping-off of cotton seedlings The relashytive pathogenicity of a large number of the fungi that were isolated from diseased cotton seedlings in Oklahoma has been ascertained by Ray and McLaughlin (52)

One of the earliest treatments that was widely used in this country in an effort to increuse the emergence und survival of cottonseed wus thut of mixing the seed with moistened wood ashes This treutment removed much of the lint and mu~t have destroyed most of the fungus mycelia und spores on the seed coat After Atkinson (12) found that the anthracnose fungus was carried on the seed he demonstrated that it could be eliminated in some lots of seed by treutment with hot watetmiddot Other heut trcutments werE used by Duggar and Cuuthen (21) Barre (17) Lipscomb and (orley (~1) und Lehman (il) with the same objective Barre (16) found that delinting with sulfuric acid effectively eliminuted external infestation by G osJlti and reduced seedling losses thut resulted from infection by thiR fungus Further developments (18 11) in the use of acids for this purpose have led to the development of commetcial plants thaI deJint seed under the Brown-Streets (O) and Kcmgas patents (11) which use HSO bull and gaseous HOI respectively

Barre (10 and Duggar and Cauthen (28) were among the first to attempt to disinfect fuzzy cottonseed with such chemicals us copper sulfate mercuric chloride and formaldehyde lhese treutshyments wete only patmiddottiall~ eflective and eflective treatment with a fungicide became posHible onl~ when the organic ml~rcurials beshycame available later Initial studies of these chemicals (88 14 35 44 58 61 68 (0) had etablihecl by 1980 the effectiveness of ethyl mercuric chloride as a fungicide for the treatment of cottonshyseeds

In formation 011 the ptevalence and distributioll of the several puthogens infecting cotton eedlings that was obtained in COIlshy

current studies with those reported in this bulletin has already been published (i5 61) Summaries of some local data have also been published elsewhere (8 80 48 iLl) as have also data on related phases of these studies (15 Hi 17 65 66)

I~X PImiddotrOM 1middotNTt I PBOCEJ)IH E bull OIlIECIIVES ANn LOCONS OF Pl

Certain plantings of 1936-89 constituted (lne selies the A test The plantingfgt of the A test were made ptimati1y to ascertain the relative role of the pathogens infesting cottonseed and the facultative pathogens inhabiting the soil as causes of low seedling

bull

bull

emergence and survival Consequently the seed lots used were selected to provide wide variations in the degree of 5nfestation by the pathogens Colletotrichum fJo~sl7Jii and Fllwrium monUiforme Seed of these lots wetmiddotc treatltll with mercurial fungicides to deshy bull

7 COTTONSEED TREATMENT

bull termine the effect of these fungicides on the incidence of seedling diseases A second lleries of plantings the B test was initiated in 1988 to ascertain the relative agronomic value of fuzzy reshyginned and acid-delinted geed and also the most effective fungishycide that might be used for treatment of each kind of seed

Til these two series it was clearly demonstrated that seed treatshyment with fungicides reduced seedling losses caused by seedshyborne pathogen but the treatments used did not always eliminate extenic gceclling losse when conditions were favorable for seedshyling infection by soil-inhabiting pathogens (36 fj1) Hence a third series the e test was initiated later primarily to study the relatic protection that diflerent fungicides in varying dosages might afrOId cottOIl s([dlings against infection by both soil-inhabitshying and scpltI-bornepathogens In addition an effective fungicide as sought that would be less toxic to animals than the widely used but poisonous mercurials

Since the data from the three series of tests are most readilv ummarizecl separately the nsults from each test are dillcussed in separate sections ot this bulletill The nlrious localities at which plantings have been made and the soil charactEristics at these locations are ghen in table 1

bull ltd lot for the plantings of each 8eason were selected from

among t~pical lailable lots of planting seed on the basis of laborashytory tests TIl( iability of the seeds of the various lots (table 2) was ascerta i ned by germ ina ti ng in test tu bes on nonnutrient agar at 22 0 to 25 C (4) acid-delinted seeds that had been previously urflce-st(rilized by immersion for 2 minutes in a 025 percent solution or l[gCl in 50-lwrcent ethanol and then washed with terile water imnl(diatel )(fore they were placed on the agar Comparald( result were obtained when Cere-an-tleated fuzzy Metis were germinated in flats of steamed sand in th~ greenhouse exclpt fo lot n-F Th(se methods of ascertaining dability did not lllHs indicat~ accurateh thE relative vitalit of the serds of t1w nrious lots 01 their al)il1ty to produce seedlings in the Held sintl lot of the same dabilit produced greatly different pt)(pntqps of plants in certairl plantings tolw discugtsed later D(linted selds from which fungi were obtained are reported as internnllr infpcted (table 2) lnfe~tation of the seeds by paUlOshy~~n- was aSClrtiliIHd by glrminaiing ul1tnated fuzzy seed under -imilar lton(itiollS Thl~ 1111m)pr of healthy 8eedlings per 100 eld planted are )awd on Sl~(t1lil1g c()unt~ made 2 w(eks after the planting of the (1( in the ~illld cultures (table 2)

bull Tlw sled lots for a g-inl1 hst were asembled at one location

thoroug-hly mixed and rtquisiie portions were taken for the slpral tnatments The chemic-als u~ed for seed treatment were applild as dusts in a rotating lJarrel mix(r in which the duration of treatm(lt was generally standardized at 60 revolutions After

8 TECHNICAL BULLETIN 1025 U S DEPT 01lt AGRICUIJTURE

TABLE l-Locations at which ezperimental plantings were made in the several States and soil types at each location

Location Code I Soil type pH

Ar~ IMananna ___________ Ak-I __ __ Lintonia silt loam __ _ _ _ ___ _ 60

Gooflria Auburn _____ bullbullbull _ _ Ga-L _ _ ___ Cecil sandy loam __ bull __ bull ___ _ 60 Experiment ____ bull ___ _ Ga-2 ________ bull __ do ____________ _ bullbull _bullbullbull _____ 62 Hawkinsville _____ bull __ Ga-a ____ bull ___ bullbullbulldo_ ___________ bull ____ _____ a6

Louisiana Baton Rouge __ bullbullbull __ bull La-I bullbullbullbullbull Olivier lilt loam bull __ ___ bull __ _ 56Saint Joseph_ La-2_ ____ Sharkey silty clay loam bullbull _ ____ _ 70

MissilllippiHolly Serings _____ bullbull __ 1 Ms-4 ___ Grenada Kilt loam ____ bullbull ________ 57 Poplarvtlle_______ bull 1 Ms-L bullbullbull __ Ruston sandy loam __ bull __ _ 58 State College _ ___ bullJ MK-2 bullbullbull Catalpll 2 sandy loam _bullbull _ _ ___ 1 68 Stonevill~_ -I Ms-~ __ - Sarpy S very fine sand _________ bullbullbull 65 West Pomt_ ____ MII-D bullbullbullbullbullIHouston c1ay bull ___ bullbull _bullbull _ 80

I North Carolina I I

Goldsboro _ bull NC-3bull _ Norfolk Kandy loam_ bull _ _ bullbullbull Nashville __ bull bull NC-L do _ _ 68 Raleigh _ _ j NC-4__ Cecil fine sandy loam 68 Rocky Mount bull __INC-2 bull Norfolk sandy loam__ 64 State3ville __ _ _ NC--5__ Cecil fine sandy loam __

Oklahoma I Perkins bullbull _ j Ok-I _ _ I Canadian Iandy loam

I 61

South Carolina II Chester _ bull SC-4 bullbull _I Appling Illndy loam 52 Clemson _- SC-L _bullbull 1 Cecil sandy loam _ _ 54 Florence bull I~q-- - Dunbar sandy loam bull __ bull 54 Jefferson S0-8 Lakeland fine sand ___ 56 KathwoOlL SC-l bull I Cahaba fine Iandy loam _I 58 Pontiac bull bull ~C~_ _I Norfolk sandy loam ___ - - 1 50 Smoaks - - SC 6 _ _ Blanton fine Iand ______ bull i 56 Woodruff _ bull SCmiddot7 _bull Cecil sandy loam _ bull I 54

Texas iCollege Station _ ~t rx-1~~ ~ j Lufkin fine sandy loam 50Temple__ -J Tx-2bull Houlton black clay ifI

Tennesse Jackson Tn-2 i Lintonia silt loam _ _ _ 55Knoxville _ Tn-I Decatur Ii1ty clay loam 55

Virginia Holland_____ Va I Onllow sandy loam _ j6

1 Planting locations will be refcrJed to by this code in text to conserve spac( When more thaIj one planting in a season has been made at the same location the successive plantings Ilrc referred to as a b c and d

bull

bull

Name ulled at time the experiments were conducted With recent revisiolls

in soil classification this soil is probably Verona 1I Name u3ed at time the experiments were conducted With recent revhlions

in soil classification this soil is probably Bosket bull

9

bull

bull

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COTTONSEED TREATMENT

TA8LE 2-Characteristics of the lots of seed used in the A test 1936-99

Seedling emergence 8i per- r---shyr-I centage of seeds planted Internal

~ _____ ~_ __~_ _0 ~I infection State Code U d d Acid- I Fungi infesting of acidshy of

ntreate see s delinted untreated seeds I delinted origin an steamed sand Reeds in I seeds I - testshy

i Total IHealthy tubes I I~-6--1A-99-2~--_I--- 47 90 -C-g--F-m-__-_-_-_-__-_--_j-F-m--C-g-(-6)-a- -s-c-

36-81--- 69 40 85 Cg Iltm_~_ ______ Fm Cg (5) __ S C 36-B2 t 87 8 90 Fm____ bullbull _______________ S C 136-C---1 i5 45 89 Cg Fm ________ bullbull Cg (9) ______ S C 36-0___ 70 I) 86 Cg Fm ______ bull ___ Fm Cg (33)_ S c 36-E ____1 53 34 60 Cg Fm _________ Cg (6) ___ bull __ S C 36-F_-- 54 20 57 Cg Fm__________ Fm Cg (15)_ S C 36-G __ bullbull 50 31 84 Cg Fm__________ Cg (7) ______ S C

19$7 37-A __ _1 91 35 91 Cg Fm ___________________ bull ___ Ala 37-B1_ 80 43 88 Cg Fm__________ Cg (4) ______ Ga 37-B2 t-l 95 95 96 Fm ___________________________ S C 37-C __ _ 72 29 85 Cg Fm ____________ bull __________ Miss

f37-0__ _ 62 52 81 ICgFm _______bull _ Cg (1)------ Missa7-E- __1 69 42 78 Cg Fm__________ Cg (3) ______ S C 3i-F____ 40 40 24 Fm Xm ______________________ Okla 37-G __ 67 67 82 Fm______________ _ ________ Okla 37-H _i 79 59 80 l Cg Fm__________ Cg (2) __ __ N C

18 I I38-A __j 54 50 90 I Fm Rn ___ bull _______ bull _____ bullbull _ __ Calif 38-B 6__ 35 33 72 I Fm Rn Xm _____ ------------ Okla38-C __ l 80 22 84 Cg Fm ______ bull ___ Cg (3) ______ S C 38-0L __ 72 14 80 Cg Fm __________ Cg (4) ______ S C 38-02 1bullbull j 77 75 88 Fm ______ bull____________________ S C 38-EL 66 17 82 Cg Fm ___ bull ______ Cg (4) ______ S C 38-E2 __ 1 80 70 81 Cg Fm________ -- _ _________ S C 38-F___ l is 56 90 Cg Fm _________ Cg (2)_ ___ NC

1939 I ~t~==~ ~ ~~ ~F~pmiddotRn~-xniI-Xril~ gk~39-Cl__ 66 58 90 Cg Fm __ bull____ __ Cg______ bull ___ N C a9-C_ 1_ 90 90 90 I F N C 39-0bull 71 18 91 1 C~-F-R__~~nfi(10)--= SC 39-E ___ i 54 37 90 ICg Fm Rn ______ 1 Cg (9) ______ Miss 39-F __ 1 52 28 i3 Cg Fm ____ bull _____ ____________ Ga

39~~__ ~~ _ 37 ____~~_J~m~n Fsp_- __ ) bullbull __ _ _ _ _ _ _ Tex

t The several species of fungi are indicated as follows Cg = Colletotrichum gossypii Fm = Fllsarium11l1l1liliorme Fsp = FU8arium spp Rn=Rhizopus tligriCIJIIS Xm = XallthomOllaH maivacearllllt

~ Individual lots of seed are designated by the letter or letter and numeral following the number used to designate the year in which it was planted

1 Number of fleedlingll obtained from 100 acid-delinted seeds that were infected by C gossYllii are indicated by numbers in parentheses

bull Lots with 2 after the designating letter are the somiddotcalled 2-year-old seed or seed from next to the last crop preceding the year in which used a11d are of the lIame variety as the preceding lot of 1-year-old seed designated by the same letter and I which was usually grown in the same locality

54-year-old seed II ayear-old seed

10 TECH~ICAT BULJI~TINI025 U s D1wr OF AGHlCUrrUlm

treatment the sublots were divided into the requisite amounts for shipment to the cooperators Generally all treatments were made bull during the last 2 weeks in March while the individual field plantshyings were macle from the first week in April to the first week in May

The acid-delinted seed used in the experiments in 1936 1937 1940 and 1942 were delinted with concentrated sulfuric acid then washed over a sieve with a stream of water and finally immersed for 3 minutes in water containing an excess of CaCO The seed were again washed to remove the adhering carbonate and then dried on a wire sueen at about 25 C for not less than 24 hours before bagging rrhe acid-delinted seed used in the B tests of 1938 and 1939 were prepared by essentially the same method except for the omission of CaCO The delinted seed used in 1941 were prepaled at a commercial acid-delinting plantl) The seed after delinting were sepalatecl into two fractions the floaters and sinkshyers on the bashl of their specific gravity in comparison to that of waiel Pheil characteristics are given in the description of the seed lots lIsed ill th( B test of 1941 (see table 9) For comparison with this method of dclinting Hced delinted in the laboratory was included in foicvelal plantings

The reg-inned 01 machine-delinted sublots wcre preparcd at various gins 01 oil mills and varying quantities of lint were removed The details are given in connection with the description of seed lIsed each ~eal in the B test bull

PIOT TECIINIQUE

Replicated plotH fully randomized to permit analysis of the data by the anal~sis of variance method were used in all plantshyings The method of planting Iate of seeding and final spacing of the plants were left to the judgment of the individual cooperashywIs Generally the handling of plots approximated the general farm pJactice of the region in which thc plantings were made The several methods of planting ued ranged from hand dropping a definite number of seedH at a predetermined spacing to the use of animal-drawn onc-row plantels When planters were used the rate of seeding was calculated from the weight of the seed planted Regardless of efforts to calibnlte the planters to distribshyute about 10 Heed per foot in most plantings there were differshyclces as great aH 25 percent in the rate of seeding of the several lots of seed used in the same planting These differences were directly associated with the amount of lint on the seed However the differences in the lite of se(ling between the untreated and treated seed of the same lot generally did not exceed 3 percent a diffelence small enough to permit relatively accurate comparishysons of the effect of treatment in field plantings

r Cottonseed Dclinting COlp inc B1ufT Alk bull

11

bull

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COTTONSEED TREATMENT

The statistical analysis for most of the plantings in which mechanical planters were used are based on 4 replications of apshyproximately 500 seeds ill 50-foot rows However 100-foot rows planted at a rate of about 10 seeds per foot were used in certain plantings of the B test In the Oklahoma and Tennessee plantings in which the seed were dropped by hand a smaller number of seeds usually about 100 were planted in each replication Since in these plantings a definite number of seeds were planted the accuracy that was possible in the percentage of emergence calcushylations largely compensated fOI the smaller number of seeds planted as compared to the plantings in which mechanical planters were used All data on seedling emergence and survival are reshyported on the basis of 100 seedsu although as indicated the number of iced planted varied from 100 to 1000

C()LIEltTIO~ ~I) I~TEHIHEIATIO~ or DAIA

Because of the impotmiddottance of h~1ing companlble data from all locations on seedling emergence and survival at the time of thinshyning the following criteria were adopted for the classification of seedlings in making counts

1 EliltIYcc lind tellllhll-To include all seedlings that have raised their cotyledons abov( (free flom) the soil and have alleast one nOlllally expanded cotyledoll flce of the seed (oat SlIch geedlingR should be 1I0lmal ill appenlllllCC and not so badly disca~ed as to pn~clude survival

2 Emeryed nllli disllIscd-Seedlings of which lhe cotyledon hnve emelged from the soil reganless of whethel they are enclosed ill 01 free of the seed coat but at the time of the count arc either dead 01 so hadly (iHeasc( as to preclude survival as llIay be indicated by willing or abscnce of normal cotyledons

3 Partially c1IwJyed-Seedlings with any part showink above lhe soil bllt inslIfficiently developed to ascertain the probability of normal healthy emershygence

In actual practice it was found very difficult to obtain counts of claHses 2 and 3 that would be of value fOl statistical analysis Consequently all analyses reported in this bulletin with a few exceptions to be noted later are based on the counts of the healthy emerged seedlings

]n all plantings an eftort was made to make a seedling count at the time of thinning or at a corresponding stage of seedling deshyvelopment in those plantings that were not thinned At thi- time about tl weeks after planting most plants had ftom three to fiv~ true leaves and there was little likelihood of fLllmiddotther losses from seedling diseases This count referred to as the final seedling count was used to calculate the percentage of surviving seedlings

HAil nlllllbtmiddotrs given in the tables to show seedling emelgcnce and sLlrviv~d COllsClluently arc pelcentages 10 avoid confusion betw(len the sev(lJal senses in which pcrc()nt mijht be lIsed all diflelenccs delived from the subtraction of two percentage arc called numerical differences increases 01 decreases while percentage is used to refer to the relalive Hiz( of two cnuIg-enccs eg- when the emcrgcnce of the untreated seed was 40 percent and that of the treated seed 60 percnt the nUllIerical difference in elllergence was 20 percent but the percentage increase in elllergence for treatment was 50 percent

COTTONSEED TREATMENT

Technical Bulletin No 1025 bull December 1950

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Cottonseed Treatlnent Its Effect on Seedling Enlcrgcnce Seedling Survival Plant Slands

and Yields 1

By Tin CO~IIITTEE O~ COTTON SEEl)LlM~ DISKSES OF TilE COTTON

DISEASE COUNCIL ~

Unitcd States Departmcnt of Agri(lIltllrc Bureau of Pia III Industry Soils and Agricultural Engincering in cooperation with the agricultural experimiddot ment stations of Arkansas Georgia Louisiana Mississippi North Cafo) lina Oklahoma South Carolina Tennessee Texas and Virginia

CONTENTS

Introduction __ 2 Response to seed treatment as inshyfluenced by the characteristics

General summary __ B of the seed lots and environshyReview of literature__ 6 me]l~l conditions (A test) 13 Experimental procedure _ 6 Characteristics of the seed lots IS

Objectives and locations of Fungicides tested and rates of plantings __ 6 application 14

Seedling survival as influencedSelection and preparation of the by the characteristics of theseed 7 seed 14 Plot technique 10 Response to seed treatment as Collection and interpretation of influenced by weather condishy

data 11 tions 28

1 Submitted for publication May 8 1960 ~ In a cooperative undertaking of this scope it would be almost impossible

to acknowled-e all of the agencies and workers who have contributed to the work PersCllnel and facilities for the experimental work were provided by the agricultural experiment stations of the 10 States in which the work was conducted at the locations given in the bulletin and by the U S Cotton Field Stations 1936-42 inclusive Planting seeds were donated by the commereial seed companies the agricultural experiment stations or the U S Cotton Field Stations that originated or maintained each variety Chemical comshypanies that originated or marrieted the chemical seed treatments that were used donated the materials and their research specialists gave freely of their

bull services during the course of the experiments The assistance of these and others whQ have made contrihutions to this work is gratefully acknowledged

1

2 TECHNICAl BULLETIN 1025 U S DEPT OF AGRlCUlTURE

CONTENTS-CONTINUED

Response to seed treatment etc An evaluation of fungicides etc -Con -Con

Effect of seed treatment on Comparative seedling emergence emergence 32 for reginned and delinted seed 65

Effect of seed treatment on the Effect of the legree of lint reshyprogress of seedling emer- moval in reginning on eedshygence 34 ling emergence 68

Seed treatment lind postemcrshy Comparative yield for fuzzygence loss of seedlings 38 reginned and delinted seed 75

Effect of seed treatment Oil nnlll An evaluation of various fungishygtands and on the survival of cides used in the treatments 75plants from thinninl to time of picking 41 Stunds yields and statistical

analyses 83Effect of seed treatment on yiellf 47 Summary of the B test 84

Helative effect of seed tnmtment An evaluation of various fungishyon seedling survival stands cides for the treatment of C(ltshyand yields 50 tonseed (C test) 85

An evaluation of fln~icidcs on Chemicals used 85 fuzzy rc~inned anil delillfed Results in 1939 86seed (B test) 57

Results in 1940 92Objectivelil 57 Comparisons of the charactcr- Results in 1941 102

ist~cs of fuzzy rc~inncd and Results in 1942 106 dehnted seed 57 Summary of rcsults of other tests

C(flllllhfl1ativc sCdmiddotedlil~g cmcrgedllce 1941-48 108 01 uzzy an regmneu see 63

Compallltivc seedlin~ cmclgcncc Literature cited 110 for fuzzy and delinted seed 65 Appendix 115

INTBO()UCTIO~

In recent yea 11 intensive Rtudies have been made of cottonshyseedling diseases with the objective of discovering some means of reducing losses from seedling diseases and thereby increasing seedling emelge~ce and survival Control of these diseases is especially pertinent since it has been demonstrated repeatedly that early planting and a uniform Rtand of plants are essential for proshyfitable yields in areas infested by the boll weevil In view of the inadequate information on cotton-ReemiddotHing diseases especially as to their prevalence and distribution the plant pathologists conshycerned with cotton-seedling diseases in the several cotton-producshying States in 1936 constituted themselves a committee to coordinate studies on the etiology of cotton-seedling diseases and to study the possibility of control by seed treatment This bulletin summarizes the results of field plantings made in 10 States from 1936 to 1942 to evaluate valious seed treatments and also to ascertain the extent to which the rlsponse to seed treatment was correlated with characteristics of each lot of cottonseed

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FOREWORD

The Cotton Disease Council composed of Federal and State research pathologists interested in the control of cotton diseases was organized at the meeting of the Southern Agricultural Workshyers at Jackson Miss in February 1936 The Committee on Cotton Seedling Diseases of the Council immediately planned an extensive series of seed-treatment l-tudies The fn~st series was started in Ul spring of 1936 Experiments summarized in this bulletin COl elucted from 1936 to 1942 inclusive represent work of this still shyactive committee Meager parts of the data presented here have been published by individual cooperators who participated in this work

C II Arndt of the South Carolina Agricultural Experiment Station first chairman of the committee started preparing and distributing the seed from a ~iven 10t all treated in the same manner He also stalmiddottell assembling and Rtatistically analyzing the elata Throughout the course of these studies Dr Arndt conshytinued to summarize the data to J1(lp in selecting and preparing the seed lots and to deige uniform planting plans to facilitate interpreting the data Successive chairmen particularly S G Lehman oJ the North Carolina Agricultural Experiment Station and 1) )L Simpson 01 the Lnited States Department of Agriculshyture cooperating with the Tennesee Agricultural Experiment Station han contributed much thought time and energy to the work Other committee chairmen associated for a shorter period of time ith thee tultiiC w(re L E vriles deceased and his uccessor J A Pir ~kard Both were jointly employed by the [jsisslppi -gricultural EXlwriment Station and the 1nited States Departnwnt of Agriculture

Other cOl11mittet nwmbers who have been acti(~ participants in the studies are G E Altntt (College Station Tex) H D Barker (Washington D el L ]f Blank (College Station Tex) K S Chest(r (Stillwater Okla) U R Gore (Experiment Ga) D C Neal (Baton Hogue La) W W Ray (Stillwater Okla) C H Rogers (Temple Tex) A L Smith (Experiment Ga) A J Lillshystrup (CI(msol1 S C) S A Wingclrd (Blacksburg Va) and V IIYOLng CFavetteilleArk) As llotedin the acknowledgshyment pag( 1 many agencie and workers other than those here mentioned have contributed to this cooperative undertaking All who are familiar with trw work however will agree that C H Arndt has clone the Imlk of tIll wO~k including the analyzing and assembling of the data [or publication

H D BA[lKER pIiuriwi lutlhJisl Dilis1 of CaNol Llti OfIf Fiber Crups (wci niSCClilCII

U11I(W Id Plalll idm1Iry So[(s ami AJlj(l(liul(tl BIIJillCCrillJ AyricIlulal [(Isnp(h Aill1lillistratio) bull

bull

3 COTTONSEED TREATMENT

GENERAl SUMMARY

The increa~es in seedling emergence seedling survival and plant tands that resulted from the treatment of cottonseed with an effective fungicide were greatest for fuzzy seed that were infested by the anthracnaso furgus Colletotrichwm goss1fpii when soil condition~ and temperature were favorable for seedling infection by thiH fungus Large increases were also obtainHt with several lots of fuzzy seed that were infested by Rhizopus nigricnns Treatshyment of lots of fuzzy seed of good viability and not infested by either of the aboe fungi generally resulted in only small increases in seedling emergence and survival even when the percentage of seedling emergence was low Treatment of lots of low viability usually resulted in larger increases than did the treatment of lots of higher iability when thf lots were comparable in other reshyspects The increa-es that resulted from seed treatment regardless of the characteristics of the lot of seed tended to be larger in early plantings in which emergence was orten delayed by cool rainy weather than in later plantings when weather conditions were uStl~llly more favora e for rapid seedling emergence and growth

The more cfrectie fungicides used in these tests did not always increase seedling emergence and prevent damping-off when condishytions were fworable 101 infection of the seedlings by soil-inhabit shying pathogens which indicates that they acted lalgely as seed di~inf(ctlnts rather than as seedling protectants However in ie(ral pladings in which two or more seedling counts were made the treatment of seed lots not infested by C gossypi-i did result in reduced damping-off as well as a lesseuror number of lesions on the hypocotyls of surviving seedlings The instances in which seed treatment failed to increase emergence were more frequent on the hea soil of the Jfississippi Delta than on lighter and better cI ra i ned soils Isolations from diseased seedl i ngs obtained from these plantings showed that bacteria Fl)coiwn lIlollilifornle other fuaria Rhioclollia ()iali an(1 nliOtlS other soil-inhabiting pathogen had inf(cterJ thp seeds and seedlings

pecial tlsts of the ((fect of tJpclting cottonseed with organic I1wrcurial that diffpr(d gnatly in such characteristics as water -olubility and volatility in(icatNj that the cffectieness of this trlatm~~nt lt1 not HSiociatld with a definite physical-chemical property It n shown however that relatively large amounts of CQm para thely Olil tile btl t Iionolu ble mercu rial were less toxic to cotton seedlings a- indicated hy emergence of eed treated with them the1 les olalile and more soluble mercurials Although relathely nonolatilc mercurials efIectiely eliminated Reed-borne pathogens rendts with other chemicals geemed to Rhow that a funshygicide must be olatile to some degree if it is to be an effective chemical for the treatment of fuzzy and Ieginned seed Volatile and nOlwolatile fungicides wer( equally effecthe for the heatment of add-delinted cottons(((1

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4 TECHNICAL BULLETIN 1025 U S DEPT OF AGRICUITURE

Seed treatment increased final stands to a much smaller extent than it increased seedling emergence and survival This was bull largely accounted for by the fact that a much heavier rate of seeding was used than was necessary to produce a stand of plants in most plantings Plant-stand counts were made after thinning and again at the time of picking in a number of plantings Losses during this interval averaged slightly less than 10 percent but were occasionally greater than 20 percent Analysis of the data showed no correlation between after-thinning losses and treatshyment or characteristics of the seed Apparently the seed-borne pathogens had no direct relation to the agents that kill cotton plants after the seedling stage

In most plantings seed treatment produced no increases or only small increases in yield This should logically be expected from the generally small differences in residual stand after thinning beshytween the untreated and treated seed However occasional inshycreases in yield as great as 20 percent were obtained and in the A tests of 1936-39 the mean increases for lots infested by C g08~ypii generally ranged from 7 to 12 percent The failure of seed treatment to produce increased yields in every planting does not invalidate the general belief that the treatment of cottonseed is a good practice since the usual small increases and occasional larger increases in yield fully compensate for the expense and inshyconveniences associated with seed treatment

Seed treatment also may be considered good insurance against the low yields usually associated with replanting in seasons when untreated seed will not produce an adequate stand at the usual bull time of planting The results obtained in these plantings have demonstrated that seed treated with an effective fungicide will generally produce a larger and more uniform stand of plants than untreated seed Consequently seed treatment may be used as a means of obtaining an adequate stand of p1ants for optimal yields from a smaller number of seeds

The response to treatment of reginned seed (seed from which part of the linters was removed in a second ginning) was freshyquently different from that of fuzzy seed from the same lot In some instances the emergence of the untreated reginned seed was much greater than that of the untreated fuzzy seed and conseshyquently the response of reginned seed to treatment was much smaller It is presumed that these differences in some manner were associated with a reduction in the amount of infective myceliti and spores of C gossypii during reginning Observations on the temperature of the seed mass during reginning showed that the maximal temperature attained wes not high enough to kill the bull anthracnose fungus

With other lots of seed the emergence of the untreated reginned

bull

seed was about the same or slightly lower than that of the correshysponding untreated fuzzy seed and the seed treatment resulted in comparable increases for both Heavily reginned seed tended to

5 COTTONSEED TREATMENT

bull give a larger response to treatment than less heavily reginned seed Since scarification of the seed coat tended to increase with the amount of lint removed it is likely that the high response of certain lots of reginned seed to treatment was in some manner associated with the scarification of the seed coat in reginning

Treatment of acid-delinted seed with fungicides generally reshysulted in only small increases in seedling emergence although there were large increases in several plantings in which emergence was delayed by cool rainy weather The testae of acid-delinted seed are very slisceptible to invasion by saprophytic fungi and when emergence is delayed such fungi may kill the young seedshylings Although the treatment of acid-delinted seed with a fungishycide usually produced only small increases in seedling emergence treatment appears to be fully justified because of the occasional large increases in emergence

Regardless of the occasional instances in which fuzzy seed tended to emerge more slowly than reginned and delinted seed no superiority in ability to produce stands of plants or yields was shown for reginned delinted or water-graded delinted seed as compared to that of fuzzy seed when these three kinds of seed were treated with an effective fungicide The results of these plantings would indicate that any advantage that one of these types of seed may have in comparison to another must lie in some convenience related to agronomic practice

HEVIEW OF L1TERATFHE

Previollsly published observations dating from those of Atkinshy)on (UU)1 have ascribed damping-off to Rhizoctonia solani Kuehn (36 gt2 61) CollelotrichllnL gossypii South4 (1 15 32) Fll-sariwn vasinfectum Atk (gt6) other fusaria (51 5n Scleroshytililit rolj-sii Sacco (16) Pythiwn ultimum Trow (2) Phymatoshytrichwn omniVOium (Shear) Duggar (53) and Thielaviopsis basicola (Berk) Ferraris (50) It has been supposed that F-U8arshyium moniliorlHe Sheldon also might be the cause of damping-off although there arl no published observations to this effect This funguil however has been definitely shown to invade cotton roots (61) The possibility of seedling infection arising from seed-borne C gossypii was first ciemolutrated by Atkinson (11) and later emphasized by Barre (Vi) and Edg-erton (24) Experiments by Rolfs (55) and by lltaulwetter (27) have shown that Xanthomona4 malvacealuln (E F Sm) Dowson also may be seed-borne F vasshyinfectum has been reported as a seed-borne disease (25 56 60) Many other fungi have been ifiolated from the interior of cottonshyseeds (22) There is still some question however as to whether any of the seed-borne bacteria and fungi except C gossypii and

I Italic numbers in parentheses refer to Literature Cited p 110 I This name is used for the anthracnose fungus in this paper instead of

Glomrella gOllsYJJii (South) Edg becliuse of the unltcrtuinty of the identity of C gOllllllpii with the Glomrrtlilt isoilited by Edgerton (57)bull

6 TECH~ICAL BULBTIN 102 tT S DEPT OF AGRICULTURJltJ

possibly X malvace(poundrum and F moniliforme are an economically important cause of the damping-off of cotton seedlings The relashytive pathogenicity of a large number of the fungi that were isolated from diseased cotton seedlings in Oklahoma has been ascertained by Ray and McLaughlin (52)

One of the earliest treatments that was widely used in this country in an effort to increuse the emergence und survival of cottonseed wus thut of mixing the seed with moistened wood ashes This treutment removed much of the lint and mu~t have destroyed most of the fungus mycelia und spores on the seed coat After Atkinson (12) found that the anthracnose fungus was carried on the seed he demonstrated that it could be eliminated in some lots of seed by treutment with hot watetmiddot Other heut trcutments werE used by Duggar and Cuuthen (21) Barre (17) Lipscomb and (orley (~1) und Lehman (il) with the same objective Barre (16) found that delinting with sulfuric acid effectively eliminuted external infestation by G osJlti and reduced seedling losses thut resulted from infection by thiR fungus Further developments (18 11) in the use of acids for this purpose have led to the development of commetcial plants thaI deJint seed under the Brown-Streets (O) and Kcmgas patents (11) which use HSO bull and gaseous HOI respectively

Barre (10 and Duggar and Cauthen (28) were among the first to attempt to disinfect fuzzy cottonseed with such chemicals us copper sulfate mercuric chloride and formaldehyde lhese treutshyments wete only patmiddottiall~ eflective and eflective treatment with a fungicide became posHible onl~ when the organic ml~rcurials beshycame available later Initial studies of these chemicals (88 14 35 44 58 61 68 (0) had etablihecl by 1980 the effectiveness of ethyl mercuric chloride as a fungicide for the treatment of cottonshyseeds

In formation 011 the ptevalence and distributioll of the several puthogens infecting cotton eedlings that was obtained in COIlshy

current studies with those reported in this bulletin has already been published (i5 61) Summaries of some local data have also been published elsewhere (8 80 48 iLl) as have also data on related phases of these studies (15 Hi 17 65 66)

I~X PImiddotrOM 1middotNTt I PBOCEJ)IH E bull OIlIECIIVES ANn LOCONS OF Pl

Certain plantings of 1936-89 constituted (lne selies the A test The plantingfgt of the A test were made ptimati1y to ascertain the relative role of the pathogens infesting cottonseed and the facultative pathogens inhabiting the soil as causes of low seedling

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emergence and survival Consequently the seed lots used were selected to provide wide variations in the degree of 5nfestation by the pathogens Colletotrichum fJo~sl7Jii and Fllwrium monUiforme Seed of these lots wetmiddotc treatltll with mercurial fungicides to deshy bull

7 COTTONSEED TREATMENT

bull termine the effect of these fungicides on the incidence of seedling diseases A second lleries of plantings the B test was initiated in 1988 to ascertain the relative agronomic value of fuzzy reshyginned and acid-delinted geed and also the most effective fungishycide that might be used for treatment of each kind of seed

Til these two series it was clearly demonstrated that seed treatshyment with fungicides reduced seedling losses caused by seedshyborne pathogen but the treatments used did not always eliminate extenic gceclling losse when conditions were favorable for seedshyling infection by soil-inhabiting pathogens (36 fj1) Hence a third series the e test was initiated later primarily to study the relatic protection that diflerent fungicides in varying dosages might afrOId cottOIl s([dlings against infection by both soil-inhabitshying and scpltI-bornepathogens In addition an effective fungicide as sought that would be less toxic to animals than the widely used but poisonous mercurials

Since the data from the three series of tests are most readilv ummarizecl separately the nsults from each test are dillcussed in separate sections ot this bulletill The nlrious localities at which plantings have been made and the soil charactEristics at these locations are ghen in table 1

bull ltd lot for the plantings of each 8eason were selected from

among t~pical lailable lots of planting seed on the basis of laborashytory tests TIl( iability of the seeds of the various lots (table 2) was ascerta i ned by germ ina ti ng in test tu bes on nonnutrient agar at 22 0 to 25 C (4) acid-delinted seeds that had been previously urflce-st(rilized by immersion for 2 minutes in a 025 percent solution or l[gCl in 50-lwrcent ethanol and then washed with terile water imnl(diatel )(fore they were placed on the agar Comparald( result were obtained when Cere-an-tleated fuzzy Metis were germinated in flats of steamed sand in th~ greenhouse exclpt fo lot n-F Th(se methods of ascertaining dability did not lllHs indicat~ accurateh thE relative vitalit of the serds of t1w nrious lots 01 their al)il1ty to produce seedlings in the Held sintl lot of the same dabilit produced greatly different pt)(pntqps of plants in certairl plantings tolw discugtsed later D(linted selds from which fungi were obtained are reported as internnllr infpcted (table 2) lnfe~tation of the seeds by paUlOshy~~n- was aSClrtiliIHd by glrminaiing ul1tnated fuzzy seed under -imilar lton(itiollS Thl~ 1111m)pr of healthy 8eedlings per 100 eld planted are )awd on Sl~(t1lil1g c()unt~ made 2 w(eks after the planting of the (1( in the ~illld cultures (table 2)

bull Tlw sled lots for a g-inl1 hst were asembled at one location

thoroug-hly mixed and rtquisiie portions were taken for the slpral tnatments The chemic-als u~ed for seed treatment were applild as dusts in a rotating lJarrel mix(r in which the duration of treatm(lt was generally standardized at 60 revolutions After

8 TECHNICAL BULLETIN 1025 U S DEPT 01lt AGRICUIJTURE

TABLE l-Locations at which ezperimental plantings were made in the several States and soil types at each location

Location Code I Soil type pH

Ar~ IMananna ___________ Ak-I __ __ Lintonia silt loam __ _ _ _ ___ _ 60

Gooflria Auburn _____ bullbullbull _ _ Ga-L _ _ ___ Cecil sandy loam __ bull __ bull ___ _ 60 Experiment ____ bull ___ _ Ga-2 ________ bull __ do ____________ _ bullbull _bullbullbull _____ 62 Hawkinsville _____ bull __ Ga-a ____ bull ___ bullbullbulldo_ ___________ bull ____ _____ a6

Louisiana Baton Rouge __ bullbullbull __ bull La-I bullbullbullbullbull Olivier lilt loam bull __ ___ bull __ _ 56Saint Joseph_ La-2_ ____ Sharkey silty clay loam bullbull _ ____ _ 70

MissilllippiHolly Serings _____ bullbull __ 1 Ms-4 ___ Grenada Kilt loam ____ bullbull ________ 57 Poplarvtlle_______ bull 1 Ms-L bullbullbull __ Ruston sandy loam __ bull __ _ 58 State College _ ___ bullJ MK-2 bullbullbull Catalpll 2 sandy loam _bullbull _ _ ___ 1 68 Stonevill~_ -I Ms-~ __ - Sarpy S very fine sand _________ bullbullbull 65 West Pomt_ ____ MII-D bullbullbullbullbullIHouston c1ay bull ___ bullbull _bullbull _ 80

I North Carolina I I

Goldsboro _ bull NC-3bull _ Norfolk Kandy loam_ bull _ _ bullbullbull Nashville __ bull bull NC-L do _ _ 68 Raleigh _ _ j NC-4__ Cecil fine sandy loam 68 Rocky Mount bull __INC-2 bull Norfolk sandy loam__ 64 State3ville __ _ _ NC--5__ Cecil fine sandy loam __

Oklahoma I Perkins bullbull _ j Ok-I _ _ I Canadian Iandy loam

I 61

South Carolina II Chester _ bull SC-4 bullbull _I Appling Illndy loam 52 Clemson _- SC-L _bullbull 1 Cecil sandy loam _ _ 54 Florence bull I~q-- - Dunbar sandy loam bull __ bull 54 Jefferson S0-8 Lakeland fine sand ___ 56 KathwoOlL SC-l bull I Cahaba fine Iandy loam _I 58 Pontiac bull bull ~C~_ _I Norfolk sandy loam ___ - - 1 50 Smoaks - - SC 6 _ _ Blanton fine Iand ______ bull i 56 Woodruff _ bull SCmiddot7 _bull Cecil sandy loam _ bull I 54

Texas iCollege Station _ ~t rx-1~~ ~ j Lufkin fine sandy loam 50Temple__ -J Tx-2bull Houlton black clay ifI

Tennesse Jackson Tn-2 i Lintonia silt loam _ _ _ 55Knoxville _ Tn-I Decatur Ii1ty clay loam 55

Virginia Holland_____ Va I Onllow sandy loam _ j6

1 Planting locations will be refcrJed to by this code in text to conserve spac( When more thaIj one planting in a season has been made at the same location the successive plantings Ilrc referred to as a b c and d

bull

bull

Name ulled at time the experiments were conducted With recent revisiolls

in soil classification this soil is probably Verona 1I Name u3ed at time the experiments were conducted With recent revhlions

in soil classification this soil is probably Bosket bull

9

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COTTONSEED TREATMENT

TA8LE 2-Characteristics of the lots of seed used in the A test 1936-99

Seedling emergence 8i per- r---shyr-I centage of seeds planted Internal

~ _____ ~_ __~_ _0 ~I infection State Code U d d Acid- I Fungi infesting of acidshy of

ntreate see s delinted untreated seeds I delinted origin an steamed sand Reeds in I seeds I - testshy

i Total IHealthy tubes I I~-6--1A-99-2~--_I--- 47 90 -C-g--F-m-__-_-_-_-__-_--_j-F-m--C-g-(-6)-a- -s-c-

36-81--- 69 40 85 Cg Iltm_~_ ______ Fm Cg (5) __ S C 36-B2 t 87 8 90 Fm____ bullbull _______________ S C 136-C---1 i5 45 89 Cg Fm ________ bullbull Cg (9) ______ S C 36-0___ 70 I) 86 Cg Fm ______ bull ___ Fm Cg (33)_ S c 36-E ____1 53 34 60 Cg Fm _________ Cg (6) ___ bull __ S C 36-F_-- 54 20 57 Cg Fm__________ Fm Cg (15)_ S C 36-G __ bullbull 50 31 84 Cg Fm__________ Cg (7) ______ S C

19$7 37-A __ _1 91 35 91 Cg Fm ___________________ bull ___ Ala 37-B1_ 80 43 88 Cg Fm__________ Cg (4) ______ Ga 37-B2 t-l 95 95 96 Fm ___________________________ S C 37-C __ _ 72 29 85 Cg Fm ____________ bull __________ Miss

f37-0__ _ 62 52 81 ICgFm _______bull _ Cg (1)------ Missa7-E- __1 69 42 78 Cg Fm__________ Cg (3) ______ S C 3i-F____ 40 40 24 Fm Xm ______________________ Okla 37-G __ 67 67 82 Fm______________ _ ________ Okla 37-H _i 79 59 80 l Cg Fm__________ Cg (2) __ __ N C

18 I I38-A __j 54 50 90 I Fm Rn ___ bull _______ bull _____ bullbull _ __ Calif 38-B 6__ 35 33 72 I Fm Rn Xm _____ ------------ Okla38-C __ l 80 22 84 Cg Fm ______ bull ___ Cg (3) ______ S C 38-0L __ 72 14 80 Cg Fm __________ Cg (4) ______ S C 38-02 1bullbull j 77 75 88 Fm ______ bull____________________ S C 38-EL 66 17 82 Cg Fm ___ bull ______ Cg (4) ______ S C 38-E2 __ 1 80 70 81 Cg Fm________ -- _ _________ S C 38-F___ l is 56 90 Cg Fm _________ Cg (2)_ ___ NC

1939 I ~t~==~ ~ ~~ ~F~pmiddotRn~-xniI-Xril~ gk~39-Cl__ 66 58 90 Cg Fm __ bull____ __ Cg______ bull ___ N C a9-C_ 1_ 90 90 90 I F N C 39-0bull 71 18 91 1 C~-F-R__~~nfi(10)--= SC 39-E ___ i 54 37 90 ICg Fm Rn ______ 1 Cg (9) ______ Miss 39-F __ 1 52 28 i3 Cg Fm ____ bull _____ ____________ Ga

39~~__ ~~ _ 37 ____~~_J~m~n Fsp_- __ ) bullbull __ _ _ _ _ _ _ Tex

t The several species of fungi are indicated as follows Cg = Colletotrichum gossypii Fm = Fllsarium11l1l1liliorme Fsp = FU8arium spp Rn=Rhizopus tligriCIJIIS Xm = XallthomOllaH maivacearllllt

~ Individual lots of seed are designated by the letter or letter and numeral following the number used to designate the year in which it was planted

1 Number of fleedlingll obtained from 100 acid-delinted seeds that were infected by C gossYllii are indicated by numbers in parentheses

bull Lots with 2 after the designating letter are the somiddotcalled 2-year-old seed or seed from next to the last crop preceding the year in which used a11d are of the lIame variety as the preceding lot of 1-year-old seed designated by the same letter and I which was usually grown in the same locality

54-year-old seed II ayear-old seed

10 TECH~ICAT BULJI~TINI025 U s D1wr OF AGHlCUrrUlm

treatment the sublots were divided into the requisite amounts for shipment to the cooperators Generally all treatments were made bull during the last 2 weeks in March while the individual field plantshyings were macle from the first week in April to the first week in May

The acid-delinted seed used in the experiments in 1936 1937 1940 and 1942 were delinted with concentrated sulfuric acid then washed over a sieve with a stream of water and finally immersed for 3 minutes in water containing an excess of CaCO The seed were again washed to remove the adhering carbonate and then dried on a wire sueen at about 25 C for not less than 24 hours before bagging rrhe acid-delinted seed used in the B tests of 1938 and 1939 were prepared by essentially the same method except for the omission of CaCO The delinted seed used in 1941 were prepaled at a commercial acid-delinting plantl) The seed after delinting were sepalatecl into two fractions the floaters and sinkshyers on the bashl of their specific gravity in comparison to that of waiel Pheil characteristics are given in the description of the seed lots lIsed ill th( B test of 1941 (see table 9) For comparison with this method of dclinting Hced delinted in the laboratory was included in foicvelal plantings

The reg-inned 01 machine-delinted sublots wcre preparcd at various gins 01 oil mills and varying quantities of lint were removed The details are given in connection with the description of seed lIsed each ~eal in the B test bull

PIOT TECIINIQUE

Replicated plotH fully randomized to permit analysis of the data by the anal~sis of variance method were used in all plantshyings The method of planting Iate of seeding and final spacing of the plants were left to the judgment of the individual cooperashywIs Generally the handling of plots approximated the general farm pJactice of the region in which thc plantings were made The several methods of planting ued ranged from hand dropping a definite number of seedH at a predetermined spacing to the use of animal-drawn onc-row plantels When planters were used the rate of seeding was calculated from the weight of the seed planted Regardless of efforts to calibnlte the planters to distribshyute about 10 Heed per foot in most plantings there were differshyclces as great aH 25 percent in the rate of seeding of the several lots of seed used in the same planting These differences were directly associated with the amount of lint on the seed However the differences in the lite of se(ling between the untreated and treated seed of the same lot generally did not exceed 3 percent a diffelence small enough to permit relatively accurate comparishysons of the effect of treatment in field plantings

r Cottonseed Dclinting COlp inc B1ufT Alk bull

11

bull

bull

COTTONSEED TREATMENT

The statistical analysis for most of the plantings in which mechanical planters were used are based on 4 replications of apshyproximately 500 seeds ill 50-foot rows However 100-foot rows planted at a rate of about 10 seeds per foot were used in certain plantings of the B test In the Oklahoma and Tennessee plantings in which the seed were dropped by hand a smaller number of seeds usually about 100 were planted in each replication Since in these plantings a definite number of seeds were planted the accuracy that was possible in the percentage of emergence calcushylations largely compensated fOI the smaller number of seeds planted as compared to the plantings in which mechanical planters were used All data on seedling emergence and survival are reshyported on the basis of 100 seedsu although as indicated the number of iced planted varied from 100 to 1000

C()LIEltTIO~ ~I) I~TEHIHEIATIO~ or DAIA

Because of the impotmiddottance of h~1ing companlble data from all locations on seedling emergence and survival at the time of thinshyning the following criteria were adopted for the classification of seedlings in making counts

1 EliltIYcc lind tellllhll-To include all seedlings that have raised their cotyledons abov( (free flom) the soil and have alleast one nOlllally expanded cotyledoll flce of the seed (oat SlIch geedlingR should be 1I0lmal ill appenlllllCC and not so badly disca~ed as to pn~clude survival

2 Emeryed nllli disllIscd-Seedlings of which lhe cotyledon hnve emelged from the soil reganless of whethel they are enclosed ill 01 free of the seed coat but at the time of the count arc either dead 01 so hadly (iHeasc( as to preclude survival as llIay be indicated by willing or abscnce of normal cotyledons

3 Partially c1IwJyed-Seedlings with any part showink above lhe soil bllt inslIfficiently developed to ascertain the probability of normal healthy emershygence

In actual practice it was found very difficult to obtain counts of claHses 2 and 3 that would be of value fOl statistical analysis Consequently all analyses reported in this bulletin with a few exceptions to be noted later are based on the counts of the healthy emerged seedlings

]n all plantings an eftort was made to make a seedling count at the time of thinning or at a corresponding stage of seedling deshyvelopment in those plantings that were not thinned At thi- time about tl weeks after planting most plants had ftom three to fiv~ true leaves and there was little likelihood of fLllmiddotther losses from seedling diseases This count referred to as the final seedling count was used to calculate the percentage of surviving seedlings

HAil nlllllbtmiddotrs given in the tables to show seedling emelgcnce and sLlrviv~d COllsClluently arc pelcentages 10 avoid confusion betw(len the sev(lJal senses in which pcrc()nt mijht be lIsed all diflelenccs delived from the subtraction of two percentage arc called numerical differences increases 01 decreases while percentage is used to refer to the relalive Hiz( of two cnuIg-enccs eg- when the emcrgcnce of the untreated seed was 40 percent and that of the treated seed 60 percnt the nUllIerical difference in elllergence was 20 percent but the percentage increase in elllergence for treatment was 50 percent

2 TECHNICAl BULLETIN 1025 U S DEPT OF AGRlCUlTURE

CONTENTS-CONTINUED

Response to seed treatment etc An evaluation of fungicides etc -Con -Con

Effect of seed treatment on Comparative seedling emergence emergence 32 for reginned and delinted seed 65

Effect of seed treatment on the Effect of the legree of lint reshyprogress of seedling emer- moval in reginning on eedshygence 34 ling emergence 68

Seed treatment lind postemcrshy Comparative yield for fuzzygence loss of seedlings 38 reginned and delinted seed 75

Effect of seed treatment Oil nnlll An evaluation of various fungishygtands and on the survival of cides used in the treatments 75plants from thinninl to time of picking 41 Stunds yields and statistical

analyses 83Effect of seed treatment on yiellf 47 Summary of the B test 84

Helative effect of seed tnmtment An evaluation of various fungishyon seedling survival stands cides for the treatment of C(ltshyand yields 50 tonseed (C test) 85

An evaluation of fln~icidcs on Chemicals used 85 fuzzy rc~inned anil delillfed Results in 1939 86seed (B test) 57

Results in 1940 92Objectivelil 57 Comparisons of the charactcr- Results in 1941 102

ist~cs of fuzzy rc~inncd and Results in 1942 106 dehnted seed 57 Summary of rcsults of other tests

C(flllllhfl1ativc sCdmiddotedlil~g cmcrgedllce 1941-48 108 01 uzzy an regmneu see 63

Compallltivc seedlin~ cmclgcncc Literature cited 110 for fuzzy and delinted seed 65 Appendix 115

INTBO()UCTIO~

In recent yea 11 intensive Rtudies have been made of cottonshyseedling diseases with the objective of discovering some means of reducing losses from seedling diseases and thereby increasing seedling emelge~ce and survival Control of these diseases is especially pertinent since it has been demonstrated repeatedly that early planting and a uniform Rtand of plants are essential for proshyfitable yields in areas infested by the boll weevil In view of the inadequate information on cotton-ReemiddotHing diseases especially as to their prevalence and distribution the plant pathologists conshycerned with cotton-seedling diseases in the several cotton-producshying States in 1936 constituted themselves a committee to coordinate studies on the etiology of cotton-seedling diseases and to study the possibility of control by seed treatment This bulletin summarizes the results of field plantings made in 10 States from 1936 to 1942 to evaluate valious seed treatments and also to ascertain the extent to which the rlsponse to seed treatment was correlated with characteristics of each lot of cottonseed

bull bull

bull

bull

FOREWORD

The Cotton Disease Council composed of Federal and State research pathologists interested in the control of cotton diseases was organized at the meeting of the Southern Agricultural Workshyers at Jackson Miss in February 1936 The Committee on Cotton Seedling Diseases of the Council immediately planned an extensive series of seed-treatment l-tudies The fn~st series was started in Ul spring of 1936 Experiments summarized in this bulletin COl elucted from 1936 to 1942 inclusive represent work of this still shyactive committee Meager parts of the data presented here have been published by individual cooperators who participated in this work

C II Arndt of the South Carolina Agricultural Experiment Station first chairman of the committee started preparing and distributing the seed from a ~iven 10t all treated in the same manner He also stalmiddottell assembling and Rtatistically analyzing the elata Throughout the course of these studies Dr Arndt conshytinued to summarize the data to J1(lp in selecting and preparing the seed lots and to deige uniform planting plans to facilitate interpreting the data Successive chairmen particularly S G Lehman oJ the North Carolina Agricultural Experiment Station and 1) )L Simpson 01 the Lnited States Department of Agriculshyture cooperating with the Tennesee Agricultural Experiment Station han contributed much thought time and energy to the work Other committee chairmen associated for a shorter period of time ith thee tultiiC w(re L E vriles deceased and his uccessor J A Pir ~kard Both were jointly employed by the [jsisslppi -gricultural EXlwriment Station and the 1nited States Departnwnt of Agriculture

Other cOl11mittet nwmbers who have been acti(~ participants in the studies are G E Altntt (College Station Tex) H D Barker (Washington D el L ]f Blank (College Station Tex) K S Chest(r (Stillwater Okla) U R Gore (Experiment Ga) D C Neal (Baton Hogue La) W W Ray (Stillwater Okla) C H Rogers (Temple Tex) A L Smith (Experiment Ga) A J Lillshystrup (CI(msol1 S C) S A Wingclrd (Blacksburg Va) and V IIYOLng CFavetteilleArk) As llotedin the acknowledgshyment pag( 1 many agencie and workers other than those here mentioned have contributed to this cooperative undertaking All who are familiar with trw work however will agree that C H Arndt has clone the Imlk of tIll wO~k including the analyzing and assembling of the data [or publication

H D BA[lKER pIiuriwi lutlhJisl Dilis1 of CaNol Llti OfIf Fiber Crups (wci niSCClilCII

U11I(W Id Plalll idm1Iry So[(s ami AJlj(l(liul(tl BIIJillCCrillJ AyricIlulal [(Isnp(h Aill1lillistratio) bull

bull

3 COTTONSEED TREATMENT

GENERAl SUMMARY

The increa~es in seedling emergence seedling survival and plant tands that resulted from the treatment of cottonseed with an effective fungicide were greatest for fuzzy seed that were infested by the anthracnaso furgus Colletotrichwm goss1fpii when soil condition~ and temperature were favorable for seedling infection by thiH fungus Large increases were also obtainHt with several lots of fuzzy seed that were infested by Rhizopus nigricnns Treatshyment of lots of fuzzy seed of good viability and not infested by either of the aboe fungi generally resulted in only small increases in seedling emergence and survival even when the percentage of seedling emergence was low Treatment of lots of low viability usually resulted in larger increases than did the treatment of lots of higher iability when thf lots were comparable in other reshyspects The increa-es that resulted from seed treatment regardless of the characteristics of the lot of seed tended to be larger in early plantings in which emergence was orten delayed by cool rainy weather than in later plantings when weather conditions were uStl~llly more favora e for rapid seedling emergence and growth

The more cfrectie fungicides used in these tests did not always increase seedling emergence and prevent damping-off when condishytions were fworable 101 infection of the seedlings by soil-inhabit shying pathogens which indicates that they acted lalgely as seed di~inf(ctlnts rather than as seedling protectants However in ie(ral pladings in which two or more seedling counts were made the treatment of seed lots not infested by C gossypi-i did result in reduced damping-off as well as a lesseuror number of lesions on the hypocotyls of surviving seedlings The instances in which seed treatment failed to increase emergence were more frequent on the hea soil of the Jfississippi Delta than on lighter and better cI ra i ned soils Isolations from diseased seedl i ngs obtained from these plantings showed that bacteria Fl)coiwn lIlollilifornle other fuaria Rhioclollia ()iali an(1 nliOtlS other soil-inhabiting pathogen had inf(cterJ thp seeds and seedlings

pecial tlsts of the ((fect of tJpclting cottonseed with organic I1wrcurial that diffpr(d gnatly in such characteristics as water -olubility and volatility in(icatNj that the cffectieness of this trlatm~~nt lt1 not HSiociatld with a definite physical-chemical property It n shown however that relatively large amounts of CQm para thely Olil tile btl t Iionolu ble mercu rial were less toxic to cotton seedlings a- indicated hy emergence of eed treated with them the1 les olalile and more soluble mercurials Although relathely nonolatilc mercurials efIectiely eliminated Reed-borne pathogens rendts with other chemicals geemed to Rhow that a funshygicide must be olatile to some degree if it is to be an effective chemical for the treatment of fuzzy and Ieginned seed Volatile and nOlwolatile fungicides wer( equally effecthe for the heatment of add-delinted cottons(((1

bull

4 TECHNICAL BULLETIN 1025 U S DEPT OF AGRICUITURE

Seed treatment increased final stands to a much smaller extent than it increased seedling emergence and survival This was bull largely accounted for by the fact that a much heavier rate of seeding was used than was necessary to produce a stand of plants in most plantings Plant-stand counts were made after thinning and again at the time of picking in a number of plantings Losses during this interval averaged slightly less than 10 percent but were occasionally greater than 20 percent Analysis of the data showed no correlation between after-thinning losses and treatshyment or characteristics of the seed Apparently the seed-borne pathogens had no direct relation to the agents that kill cotton plants after the seedling stage

In most plantings seed treatment produced no increases or only small increases in yield This should logically be expected from the generally small differences in residual stand after thinning beshytween the untreated and treated seed However occasional inshycreases in yield as great as 20 percent were obtained and in the A tests of 1936-39 the mean increases for lots infested by C g08~ypii generally ranged from 7 to 12 percent The failure of seed treatment to produce increased yields in every planting does not invalidate the general belief that the treatment of cottonseed is a good practice since the usual small increases and occasional larger increases in yield fully compensate for the expense and inshyconveniences associated with seed treatment

Seed treatment also may be considered good insurance against the low yields usually associated with replanting in seasons when untreated seed will not produce an adequate stand at the usual bull time of planting The results obtained in these plantings have demonstrated that seed treated with an effective fungicide will generally produce a larger and more uniform stand of plants than untreated seed Consequently seed treatment may be used as a means of obtaining an adequate stand of p1ants for optimal yields from a smaller number of seeds

The response to treatment of reginned seed (seed from which part of the linters was removed in a second ginning) was freshyquently different from that of fuzzy seed from the same lot In some instances the emergence of the untreated reginned seed was much greater than that of the untreated fuzzy seed and conseshyquently the response of reginned seed to treatment was much smaller It is presumed that these differences in some manner were associated with a reduction in the amount of infective myceliti and spores of C gossypii during reginning Observations on the temperature of the seed mass during reginning showed that the maximal temperature attained wes not high enough to kill the bull anthracnose fungus

With other lots of seed the emergence of the untreated reginned

bull

seed was about the same or slightly lower than that of the correshysponding untreated fuzzy seed and the seed treatment resulted in comparable increases for both Heavily reginned seed tended to

5 COTTONSEED TREATMENT

bull give a larger response to treatment than less heavily reginned seed Since scarification of the seed coat tended to increase with the amount of lint removed it is likely that the high response of certain lots of reginned seed to treatment was in some manner associated with the scarification of the seed coat in reginning

Treatment of acid-delinted seed with fungicides generally reshysulted in only small increases in seedling emergence although there were large increases in several plantings in which emergence was delayed by cool rainy weather The testae of acid-delinted seed are very slisceptible to invasion by saprophytic fungi and when emergence is delayed such fungi may kill the young seedshylings Although the treatment of acid-delinted seed with a fungishycide usually produced only small increases in seedling emergence treatment appears to be fully justified because of the occasional large increases in emergence

Regardless of the occasional instances in which fuzzy seed tended to emerge more slowly than reginned and delinted seed no superiority in ability to produce stands of plants or yields was shown for reginned delinted or water-graded delinted seed as compared to that of fuzzy seed when these three kinds of seed were treated with an effective fungicide The results of these plantings would indicate that any advantage that one of these types of seed may have in comparison to another must lie in some convenience related to agronomic practice

HEVIEW OF L1TERATFHE

Previollsly published observations dating from those of Atkinshy)on (UU)1 have ascribed damping-off to Rhizoctonia solani Kuehn (36 gt2 61) CollelotrichllnL gossypii South4 (1 15 32) Fll-sariwn vasinfectum Atk (gt6) other fusaria (51 5n Scleroshytililit rolj-sii Sacco (16) Pythiwn ultimum Trow (2) Phymatoshytrichwn omniVOium (Shear) Duggar (53) and Thielaviopsis basicola (Berk) Ferraris (50) It has been supposed that F-U8arshyium moniliorlHe Sheldon also might be the cause of damping-off although there arl no published observations to this effect This funguil however has been definitely shown to invade cotton roots (61) The possibility of seedling infection arising from seed-borne C gossypii was first ciemolutrated by Atkinson (11) and later emphasized by Barre (Vi) and Edg-erton (24) Experiments by Rolfs (55) and by lltaulwetter (27) have shown that Xanthomona4 malvacealuln (E F Sm) Dowson also may be seed-borne F vasshyinfectum has been reported as a seed-borne disease (25 56 60) Many other fungi have been ifiolated from the interior of cottonshyseeds (22) There is still some question however as to whether any of the seed-borne bacteria and fungi except C gossypii and

I Italic numbers in parentheses refer to Literature Cited p 110 I This name is used for the anthracnose fungus in this paper instead of

Glomrella gOllsYJJii (South) Edg becliuse of the unltcrtuinty of the identity of C gOllllllpii with the Glomrrtlilt isoilited by Edgerton (57)bull

6 TECH~ICAL BULBTIN 102 tT S DEPT OF AGRICULTURJltJ

possibly X malvace(poundrum and F moniliforme are an economically important cause of the damping-off of cotton seedlings The relashytive pathogenicity of a large number of the fungi that were isolated from diseased cotton seedlings in Oklahoma has been ascertained by Ray and McLaughlin (52)

One of the earliest treatments that was widely used in this country in an effort to increuse the emergence und survival of cottonseed wus thut of mixing the seed with moistened wood ashes This treutment removed much of the lint and mu~t have destroyed most of the fungus mycelia und spores on the seed coat After Atkinson (12) found that the anthracnose fungus was carried on the seed he demonstrated that it could be eliminated in some lots of seed by treutment with hot watetmiddot Other heut trcutments werE used by Duggar and Cuuthen (21) Barre (17) Lipscomb and (orley (~1) und Lehman (il) with the same objective Barre (16) found that delinting with sulfuric acid effectively eliminuted external infestation by G osJlti and reduced seedling losses thut resulted from infection by thiR fungus Further developments (18 11) in the use of acids for this purpose have led to the development of commetcial plants thaI deJint seed under the Brown-Streets (O) and Kcmgas patents (11) which use HSO bull and gaseous HOI respectively

Barre (10 and Duggar and Cauthen (28) were among the first to attempt to disinfect fuzzy cottonseed with such chemicals us copper sulfate mercuric chloride and formaldehyde lhese treutshyments wete only patmiddottiall~ eflective and eflective treatment with a fungicide became posHible onl~ when the organic ml~rcurials beshycame available later Initial studies of these chemicals (88 14 35 44 58 61 68 (0) had etablihecl by 1980 the effectiveness of ethyl mercuric chloride as a fungicide for the treatment of cottonshyseeds

In formation 011 the ptevalence and distributioll of the several puthogens infecting cotton eedlings that was obtained in COIlshy

current studies with those reported in this bulletin has already been published (i5 61) Summaries of some local data have also been published elsewhere (8 80 48 iLl) as have also data on related phases of these studies (15 Hi 17 65 66)

I~X PImiddotrOM 1middotNTt I PBOCEJ)IH E bull OIlIECIIVES ANn LOCONS OF Pl

Certain plantings of 1936-89 constituted (lne selies the A test The plantingfgt of the A test were made ptimati1y to ascertain the relative role of the pathogens infesting cottonseed and the facultative pathogens inhabiting the soil as causes of low seedling

bull

bull

emergence and survival Consequently the seed lots used were selected to provide wide variations in the degree of 5nfestation by the pathogens Colletotrichum fJo~sl7Jii and Fllwrium monUiforme Seed of these lots wetmiddotc treatltll with mercurial fungicides to deshy bull

7 COTTONSEED TREATMENT

bull termine the effect of these fungicides on the incidence of seedling diseases A second lleries of plantings the B test was initiated in 1988 to ascertain the relative agronomic value of fuzzy reshyginned and acid-delinted geed and also the most effective fungishycide that might be used for treatment of each kind of seed

Til these two series it was clearly demonstrated that seed treatshyment with fungicides reduced seedling losses caused by seedshyborne pathogen but the treatments used did not always eliminate extenic gceclling losse when conditions were favorable for seedshyling infection by soil-inhabiting pathogens (36 fj1) Hence a third series the e test was initiated later primarily to study the relatic protection that diflerent fungicides in varying dosages might afrOId cottOIl s([dlings against infection by both soil-inhabitshying and scpltI-bornepathogens In addition an effective fungicide as sought that would be less toxic to animals than the widely used but poisonous mercurials

Since the data from the three series of tests are most readilv ummarizecl separately the nsults from each test are dillcussed in separate sections ot this bulletill The nlrious localities at which plantings have been made and the soil charactEristics at these locations are ghen in table 1

bull ltd lot for the plantings of each 8eason were selected from

among t~pical lailable lots of planting seed on the basis of laborashytory tests TIl( iability of the seeds of the various lots (table 2) was ascerta i ned by germ ina ti ng in test tu bes on nonnutrient agar at 22 0 to 25 C (4) acid-delinted seeds that had been previously urflce-st(rilized by immersion for 2 minutes in a 025 percent solution or l[gCl in 50-lwrcent ethanol and then washed with terile water imnl(diatel )(fore they were placed on the agar Comparald( result were obtained when Cere-an-tleated fuzzy Metis were germinated in flats of steamed sand in th~ greenhouse exclpt fo lot n-F Th(se methods of ascertaining dability did not lllHs indicat~ accurateh thE relative vitalit of the serds of t1w nrious lots 01 their al)il1ty to produce seedlings in the Held sintl lot of the same dabilit produced greatly different pt)(pntqps of plants in certairl plantings tolw discugtsed later D(linted selds from which fungi were obtained are reported as internnllr infpcted (table 2) lnfe~tation of the seeds by paUlOshy~~n- was aSClrtiliIHd by glrminaiing ul1tnated fuzzy seed under -imilar lton(itiollS Thl~ 1111m)pr of healthy 8eedlings per 100 eld planted are )awd on Sl~(t1lil1g c()unt~ made 2 w(eks after the planting of the (1( in the ~illld cultures (table 2)

bull Tlw sled lots for a g-inl1 hst were asembled at one location

thoroug-hly mixed and rtquisiie portions were taken for the slpral tnatments The chemic-als u~ed for seed treatment were applild as dusts in a rotating lJarrel mix(r in which the duration of treatm(lt was generally standardized at 60 revolutions After

8 TECHNICAL BULLETIN 1025 U S DEPT 01lt AGRICUIJTURE

TABLE l-Locations at which ezperimental plantings were made in the several States and soil types at each location

Location Code I Soil type pH

Ar~ IMananna ___________ Ak-I __ __ Lintonia silt loam __ _ _ _ ___ _ 60

Gooflria Auburn _____ bullbullbull _ _ Ga-L _ _ ___ Cecil sandy loam __ bull __ bull ___ _ 60 Experiment ____ bull ___ _ Ga-2 ________ bull __ do ____________ _ bullbull _bullbullbull _____ 62 Hawkinsville _____ bull __ Ga-a ____ bull ___ bullbullbulldo_ ___________ bull ____ _____ a6

Louisiana Baton Rouge __ bullbullbull __ bull La-I bullbullbullbullbull Olivier lilt loam bull __ ___ bull __ _ 56Saint Joseph_ La-2_ ____ Sharkey silty clay loam bullbull _ ____ _ 70

MissilllippiHolly Serings _____ bullbull __ 1 Ms-4 ___ Grenada Kilt loam ____ bullbull ________ 57 Poplarvtlle_______ bull 1 Ms-L bullbullbull __ Ruston sandy loam __ bull __ _ 58 State College _ ___ bullJ MK-2 bullbullbull Catalpll 2 sandy loam _bullbull _ _ ___ 1 68 Stonevill~_ -I Ms-~ __ - Sarpy S very fine sand _________ bullbullbull 65 West Pomt_ ____ MII-D bullbullbullbullbullIHouston c1ay bull ___ bullbull _bullbull _ 80

I North Carolina I I

Goldsboro _ bull NC-3bull _ Norfolk Kandy loam_ bull _ _ bullbullbull Nashville __ bull bull NC-L do _ _ 68 Raleigh _ _ j NC-4__ Cecil fine sandy loam 68 Rocky Mount bull __INC-2 bull Norfolk sandy loam__ 64 State3ville __ _ _ NC--5__ Cecil fine sandy loam __

Oklahoma I Perkins bullbull _ j Ok-I _ _ I Canadian Iandy loam

I 61

South Carolina II Chester _ bull SC-4 bullbull _I Appling Illndy loam 52 Clemson _- SC-L _bullbull 1 Cecil sandy loam _ _ 54 Florence bull I~q-- - Dunbar sandy loam bull __ bull 54 Jefferson S0-8 Lakeland fine sand ___ 56 KathwoOlL SC-l bull I Cahaba fine Iandy loam _I 58 Pontiac bull bull ~C~_ _I Norfolk sandy loam ___ - - 1 50 Smoaks - - SC 6 _ _ Blanton fine Iand ______ bull i 56 Woodruff _ bull SCmiddot7 _bull Cecil sandy loam _ bull I 54

Texas iCollege Station _ ~t rx-1~~ ~ j Lufkin fine sandy loam 50Temple__ -J Tx-2bull Houlton black clay ifI

Tennesse Jackson Tn-2 i Lintonia silt loam _ _ _ 55Knoxville _ Tn-I Decatur Ii1ty clay loam 55

Virginia Holland_____ Va I Onllow sandy loam _ j6

1 Planting locations will be refcrJed to by this code in text to conserve spac( When more thaIj one planting in a season has been made at the same location the successive plantings Ilrc referred to as a b c and d

bull

bull

Name ulled at time the experiments were conducted With recent revisiolls

in soil classification this soil is probably Verona 1I Name u3ed at time the experiments were conducted With recent revhlions

in soil classification this soil is probably Bosket bull

9

bull

bull

bull

COTTONSEED TREATMENT

TA8LE 2-Characteristics of the lots of seed used in the A test 1936-99

Seedling emergence 8i per- r---shyr-I centage of seeds planted Internal

~ _____ ~_ __~_ _0 ~I infection State Code U d d Acid- I Fungi infesting of acidshy of

ntreate see s delinted untreated seeds I delinted origin an steamed sand Reeds in I seeds I - testshy

i Total IHealthy tubes I I~-6--1A-99-2~--_I--- 47 90 -C-g--F-m-__-_-_-_-__-_--_j-F-m--C-g-(-6)-a- -s-c-

36-81--- 69 40 85 Cg Iltm_~_ ______ Fm Cg (5) __ S C 36-B2 t 87 8 90 Fm____ bullbull _______________ S C 136-C---1 i5 45 89 Cg Fm ________ bullbull Cg (9) ______ S C 36-0___ 70 I) 86 Cg Fm ______ bull ___ Fm Cg (33)_ S c 36-E ____1 53 34 60 Cg Fm _________ Cg (6) ___ bull __ S C 36-F_-- 54 20 57 Cg Fm__________ Fm Cg (15)_ S C 36-G __ bullbull 50 31 84 Cg Fm__________ Cg (7) ______ S C

19$7 37-A __ _1 91 35 91 Cg Fm ___________________ bull ___ Ala 37-B1_ 80 43 88 Cg Fm__________ Cg (4) ______ Ga 37-B2 t-l 95 95 96 Fm ___________________________ S C 37-C __ _ 72 29 85 Cg Fm ____________ bull __________ Miss

f37-0__ _ 62 52 81 ICgFm _______bull _ Cg (1)------ Missa7-E- __1 69 42 78 Cg Fm__________ Cg (3) ______ S C 3i-F____ 40 40 24 Fm Xm ______________________ Okla 37-G __ 67 67 82 Fm______________ _ ________ Okla 37-H _i 79 59 80 l Cg Fm__________ Cg (2) __ __ N C

18 I I38-A __j 54 50 90 I Fm Rn ___ bull _______ bull _____ bullbull _ __ Calif 38-B 6__ 35 33 72 I Fm Rn Xm _____ ------------ Okla38-C __ l 80 22 84 Cg Fm ______ bull ___ Cg (3) ______ S C 38-0L __ 72 14 80 Cg Fm __________ Cg (4) ______ S C 38-02 1bullbull j 77 75 88 Fm ______ bull____________________ S C 38-EL 66 17 82 Cg Fm ___ bull ______ Cg (4) ______ S C 38-E2 __ 1 80 70 81 Cg Fm________ -- _ _________ S C 38-F___ l is 56 90 Cg Fm _________ Cg (2)_ ___ NC

1939 I ~t~==~ ~ ~~ ~F~pmiddotRn~-xniI-Xril~ gk~39-Cl__ 66 58 90 Cg Fm __ bull____ __ Cg______ bull ___ N C a9-C_ 1_ 90 90 90 I F N C 39-0bull 71 18 91 1 C~-F-R__~~nfi(10)--= SC 39-E ___ i 54 37 90 ICg Fm Rn ______ 1 Cg (9) ______ Miss 39-F __ 1 52 28 i3 Cg Fm ____ bull _____ ____________ Ga

39~~__ ~~ _ 37 ____~~_J~m~n Fsp_- __ ) bullbull __ _ _ _ _ _ _ Tex

t The several species of fungi are indicated as follows Cg = Colletotrichum gossypii Fm = Fllsarium11l1l1liliorme Fsp = FU8arium spp Rn=Rhizopus tligriCIJIIS Xm = XallthomOllaH maivacearllllt

~ Individual lots of seed are designated by the letter or letter and numeral following the number used to designate the year in which it was planted

1 Number of fleedlingll obtained from 100 acid-delinted seeds that were infected by C gossYllii are indicated by numbers in parentheses

bull Lots with 2 after the designating letter are the somiddotcalled 2-year-old seed or seed from next to the last crop preceding the year in which used a11d are of the lIame variety as the preceding lot of 1-year-old seed designated by the same letter and I which was usually grown in the same locality

54-year-old seed II ayear-old seed

10 TECH~ICAT BULJI~TINI025 U s D1wr OF AGHlCUrrUlm

treatment the sublots were divided into the requisite amounts for shipment to the cooperators Generally all treatments were made bull during the last 2 weeks in March while the individual field plantshyings were macle from the first week in April to the first week in May

The acid-delinted seed used in the experiments in 1936 1937 1940 and 1942 were delinted with concentrated sulfuric acid then washed over a sieve with a stream of water and finally immersed for 3 minutes in water containing an excess of CaCO The seed were again washed to remove the adhering carbonate and then dried on a wire sueen at about 25 C for not less than 24 hours before bagging rrhe acid-delinted seed used in the B tests of 1938 and 1939 were prepared by essentially the same method except for the omission of CaCO The delinted seed used in 1941 were prepaled at a commercial acid-delinting plantl) The seed after delinting were sepalatecl into two fractions the floaters and sinkshyers on the bashl of their specific gravity in comparison to that of waiel Pheil characteristics are given in the description of the seed lots lIsed ill th( B test of 1941 (see table 9) For comparison with this method of dclinting Hced delinted in the laboratory was included in foicvelal plantings

The reg-inned 01 machine-delinted sublots wcre preparcd at various gins 01 oil mills and varying quantities of lint were removed The details are given in connection with the description of seed lIsed each ~eal in the B test bull

PIOT TECIINIQUE

Replicated plotH fully randomized to permit analysis of the data by the anal~sis of variance method were used in all plantshyings The method of planting Iate of seeding and final spacing of the plants were left to the judgment of the individual cooperashywIs Generally the handling of plots approximated the general farm pJactice of the region in which thc plantings were made The several methods of planting ued ranged from hand dropping a definite number of seedH at a predetermined spacing to the use of animal-drawn onc-row plantels When planters were used the rate of seeding was calculated from the weight of the seed planted Regardless of efforts to calibnlte the planters to distribshyute about 10 Heed per foot in most plantings there were differshyclces as great aH 25 percent in the rate of seeding of the several lots of seed used in the same planting These differences were directly associated with the amount of lint on the seed However the differences in the lite of se(ling between the untreated and treated seed of the same lot generally did not exceed 3 percent a diffelence small enough to permit relatively accurate comparishysons of the effect of treatment in field plantings

r Cottonseed Dclinting COlp inc B1ufT Alk bull

11

bull

bull

COTTONSEED TREATMENT

The statistical analysis for most of the plantings in which mechanical planters were used are based on 4 replications of apshyproximately 500 seeds ill 50-foot rows However 100-foot rows planted at a rate of about 10 seeds per foot were used in certain plantings of the B test In the Oklahoma and Tennessee plantings in which the seed were dropped by hand a smaller number of seeds usually about 100 were planted in each replication Since in these plantings a definite number of seeds were planted the accuracy that was possible in the percentage of emergence calcushylations largely compensated fOI the smaller number of seeds planted as compared to the plantings in which mechanical planters were used All data on seedling emergence and survival are reshyported on the basis of 100 seedsu although as indicated the number of iced planted varied from 100 to 1000

C()LIEltTIO~ ~I) I~TEHIHEIATIO~ or DAIA

Because of the impotmiddottance of h~1ing companlble data from all locations on seedling emergence and survival at the time of thinshyning the following criteria were adopted for the classification of seedlings in making counts

1 EliltIYcc lind tellllhll-To include all seedlings that have raised their cotyledons abov( (free flom) the soil and have alleast one nOlllally expanded cotyledoll flce of the seed (oat SlIch geedlingR should be 1I0lmal ill appenlllllCC and not so badly disca~ed as to pn~clude survival

2 Emeryed nllli disllIscd-Seedlings of which lhe cotyledon hnve emelged from the soil reganless of whethel they are enclosed ill 01 free of the seed coat but at the time of the count arc either dead 01 so hadly (iHeasc( as to preclude survival as llIay be indicated by willing or abscnce of normal cotyledons

3 Partially c1IwJyed-Seedlings with any part showink above lhe soil bllt inslIfficiently developed to ascertain the probability of normal healthy emershygence

In actual practice it was found very difficult to obtain counts of claHses 2 and 3 that would be of value fOl statistical analysis Consequently all analyses reported in this bulletin with a few exceptions to be noted later are based on the counts of the healthy emerged seedlings

]n all plantings an eftort was made to make a seedling count at the time of thinning or at a corresponding stage of seedling deshyvelopment in those plantings that were not thinned At thi- time about tl weeks after planting most plants had ftom three to fiv~ true leaves and there was little likelihood of fLllmiddotther losses from seedling diseases This count referred to as the final seedling count was used to calculate the percentage of surviving seedlings

HAil nlllllbtmiddotrs given in the tables to show seedling emelgcnce and sLlrviv~d COllsClluently arc pelcentages 10 avoid confusion betw(len the sev(lJal senses in which pcrc()nt mijht be lIsed all diflelenccs delived from the subtraction of two percentage arc called numerical differences increases 01 decreases while percentage is used to refer to the relalive Hiz( of two cnuIg-enccs eg- when the emcrgcnce of the untreated seed was 40 percent and that of the treated seed 60 percnt the nUllIerical difference in elllergence was 20 percent but the percentage increase in elllergence for treatment was 50 percent

bull

FOREWORD

The Cotton Disease Council composed of Federal and State research pathologists interested in the control of cotton diseases was organized at the meeting of the Southern Agricultural Workshyers at Jackson Miss in February 1936 The Committee on Cotton Seedling Diseases of the Council immediately planned an extensive series of seed-treatment l-tudies The fn~st series was started in Ul spring of 1936 Experiments summarized in this bulletin COl elucted from 1936 to 1942 inclusive represent work of this still shyactive committee Meager parts of the data presented here have been published by individual cooperators who participated in this work

C II Arndt of the South Carolina Agricultural Experiment Station first chairman of the committee started preparing and distributing the seed from a ~iven 10t all treated in the same manner He also stalmiddottell assembling and Rtatistically analyzing the elata Throughout the course of these studies Dr Arndt conshytinued to summarize the data to J1(lp in selecting and preparing the seed lots and to deige uniform planting plans to facilitate interpreting the data Successive chairmen particularly S G Lehman oJ the North Carolina Agricultural Experiment Station and 1) )L Simpson 01 the Lnited States Department of Agriculshyture cooperating with the Tennesee Agricultural Experiment Station han contributed much thought time and energy to the work Other committee chairmen associated for a shorter period of time ith thee tultiiC w(re L E vriles deceased and his uccessor J A Pir ~kard Both were jointly employed by the [jsisslppi -gricultural EXlwriment Station and the 1nited States Departnwnt of Agriculture

Other cOl11mittet nwmbers who have been acti(~ participants in the studies are G E Altntt (College Station Tex) H D Barker (Washington D el L ]f Blank (College Station Tex) K S Chest(r (Stillwater Okla) U R Gore (Experiment Ga) D C Neal (Baton Hogue La) W W Ray (Stillwater Okla) C H Rogers (Temple Tex) A L Smith (Experiment Ga) A J Lillshystrup (CI(msol1 S C) S A Wingclrd (Blacksburg Va) and V IIYOLng CFavetteilleArk) As llotedin the acknowledgshyment pag( 1 many agencie and workers other than those here mentioned have contributed to this cooperative undertaking All who are familiar with trw work however will agree that C H Arndt has clone the Imlk of tIll wO~k including the analyzing and assembling of the data [or publication

H D BA[lKER pIiuriwi lutlhJisl Dilis1 of CaNol Llti OfIf Fiber Crups (wci niSCClilCII

U11I(W Id Plalll idm1Iry So[(s ami AJlj(l(liul(tl BIIJillCCrillJ AyricIlulal [(Isnp(h Aill1lillistratio) bull

bull

3 COTTONSEED TREATMENT

GENERAl SUMMARY

The increa~es in seedling emergence seedling survival and plant tands that resulted from the treatment of cottonseed with an effective fungicide were greatest for fuzzy seed that were infested by the anthracnaso furgus Colletotrichwm goss1fpii when soil condition~ and temperature were favorable for seedling infection by thiH fungus Large increases were also obtainHt with several lots of fuzzy seed that were infested by Rhizopus nigricnns Treatshyment of lots of fuzzy seed of good viability and not infested by either of the aboe fungi generally resulted in only small increases in seedling emergence and survival even when the percentage of seedling emergence was low Treatment of lots of low viability usually resulted in larger increases than did the treatment of lots of higher iability when thf lots were comparable in other reshyspects The increa-es that resulted from seed treatment regardless of the characteristics of the lot of seed tended to be larger in early plantings in which emergence was orten delayed by cool rainy weather than in later plantings when weather conditions were uStl~llly more favora e for rapid seedling emergence and growth

The more cfrectie fungicides used in these tests did not always increase seedling emergence and prevent damping-off when condishytions were fworable 101 infection of the seedlings by soil-inhabit shying pathogens which indicates that they acted lalgely as seed di~inf(ctlnts rather than as seedling protectants However in ie(ral pladings in which two or more seedling counts were made the treatment of seed lots not infested by C gossypi-i did result in reduced damping-off as well as a lesseuror number of lesions on the hypocotyls of surviving seedlings The instances in which seed treatment failed to increase emergence were more frequent on the hea soil of the Jfississippi Delta than on lighter and better cI ra i ned soils Isolations from diseased seedl i ngs obtained from these plantings showed that bacteria Fl)coiwn lIlollilifornle other fuaria Rhioclollia ()iali an(1 nliOtlS other soil-inhabiting pathogen had inf(cterJ thp seeds and seedlings

pecial tlsts of the ((fect of tJpclting cottonseed with organic I1wrcurial that diffpr(d gnatly in such characteristics as water -olubility and volatility in(icatNj that the cffectieness of this trlatm~~nt lt1 not HSiociatld with a definite physical-chemical property It n shown however that relatively large amounts of CQm para thely Olil tile btl t Iionolu ble mercu rial were less toxic to cotton seedlings a- indicated hy emergence of eed treated with them the1 les olalile and more soluble mercurials Although relathely nonolatilc mercurials efIectiely eliminated Reed-borne pathogens rendts with other chemicals geemed to Rhow that a funshygicide must be olatile to some degree if it is to be an effective chemical for the treatment of fuzzy and Ieginned seed Volatile and nOlwolatile fungicides wer( equally effecthe for the heatment of add-delinted cottons(((1

bull

4 TECHNICAL BULLETIN 1025 U S DEPT OF AGRICUITURE

Seed treatment increased final stands to a much smaller extent than it increased seedling emergence and survival This was bull largely accounted for by the fact that a much heavier rate of seeding was used than was necessary to produce a stand of plants in most plantings Plant-stand counts were made after thinning and again at the time of picking in a number of plantings Losses during this interval averaged slightly less than 10 percent but were occasionally greater than 20 percent Analysis of the data showed no correlation between after-thinning losses and treatshyment or characteristics of the seed Apparently the seed-borne pathogens had no direct relation to the agents that kill cotton plants after the seedling stage

In most plantings seed treatment produced no increases or only small increases in yield This should logically be expected from the generally small differences in residual stand after thinning beshytween the untreated and treated seed However occasional inshycreases in yield as great as 20 percent were obtained and in the A tests of 1936-39 the mean increases for lots infested by C g08~ypii generally ranged from 7 to 12 percent The failure of seed treatment to produce increased yields in every planting does not invalidate the general belief that the treatment of cottonseed is a good practice since the usual small increases and occasional larger increases in yield fully compensate for the expense and inshyconveniences associated with seed treatment

Seed treatment also may be considered good insurance against the low yields usually associated with replanting in seasons when untreated seed will not produce an adequate stand at the usual bull time of planting The results obtained in these plantings have demonstrated that seed treated with an effective fungicide will generally produce a larger and more uniform stand of plants than untreated seed Consequently seed treatment may be used as a means of obtaining an adequate stand of p1ants for optimal yields from a smaller number of seeds

The response to treatment of reginned seed (seed from which part of the linters was removed in a second ginning) was freshyquently different from that of fuzzy seed from the same lot In some instances the emergence of the untreated reginned seed was much greater than that of the untreated fuzzy seed and conseshyquently the response of reginned seed to treatment was much smaller It is presumed that these differences in some manner were associated with a reduction in the amount of infective myceliti and spores of C gossypii during reginning Observations on the temperature of the seed mass during reginning showed that the maximal temperature attained wes not high enough to kill the bull anthracnose fungus

With other lots of seed the emergence of the untreated reginned

bull

seed was about the same or slightly lower than that of the correshysponding untreated fuzzy seed and the seed treatment resulted in comparable increases for both Heavily reginned seed tended to

5 COTTONSEED TREATMENT

bull give a larger response to treatment than less heavily reginned seed Since scarification of the seed coat tended to increase with the amount of lint removed it is likely that the high response of certain lots of reginned seed to treatment was in some manner associated with the scarification of the seed coat in reginning

Treatment of acid-delinted seed with fungicides generally reshysulted in only small increases in seedling emergence although there were large increases in several plantings in which emergence was delayed by cool rainy weather The testae of acid-delinted seed are very slisceptible to invasion by saprophytic fungi and when emergence is delayed such fungi may kill the young seedshylings Although the treatment of acid-delinted seed with a fungishycide usually produced only small increases in seedling emergence treatment appears to be fully justified because of the occasional large increases in emergence

Regardless of the occasional instances in which fuzzy seed tended to emerge more slowly than reginned and delinted seed no superiority in ability to produce stands of plants or yields was shown for reginned delinted or water-graded delinted seed as compared to that of fuzzy seed when these three kinds of seed were treated with an effective fungicide The results of these plantings would indicate that any advantage that one of these types of seed may have in comparison to another must lie in some convenience related to agronomic practice

HEVIEW OF L1TERATFHE

Previollsly published observations dating from those of Atkinshy)on (UU)1 have ascribed damping-off to Rhizoctonia solani Kuehn (36 gt2 61) CollelotrichllnL gossypii South4 (1 15 32) Fll-sariwn vasinfectum Atk (gt6) other fusaria (51 5n Scleroshytililit rolj-sii Sacco (16) Pythiwn ultimum Trow (2) Phymatoshytrichwn omniVOium (Shear) Duggar (53) and Thielaviopsis basicola (Berk) Ferraris (50) It has been supposed that F-U8arshyium moniliorlHe Sheldon also might be the cause of damping-off although there arl no published observations to this effect This funguil however has been definitely shown to invade cotton roots (61) The possibility of seedling infection arising from seed-borne C gossypii was first ciemolutrated by Atkinson (11) and later emphasized by Barre (Vi) and Edg-erton (24) Experiments by Rolfs (55) and by lltaulwetter (27) have shown that Xanthomona4 malvacealuln (E F Sm) Dowson also may be seed-borne F vasshyinfectum has been reported as a seed-borne disease (25 56 60) Many other fungi have been ifiolated from the interior of cottonshyseeds (22) There is still some question however as to whether any of the seed-borne bacteria and fungi except C gossypii and

I Italic numbers in parentheses refer to Literature Cited p 110 I This name is used for the anthracnose fungus in this paper instead of

Glomrella gOllsYJJii (South) Edg becliuse of the unltcrtuinty of the identity of C gOllllllpii with the Glomrrtlilt isoilited by Edgerton (57)bull

6 TECH~ICAL BULBTIN 102 tT S DEPT OF AGRICULTURJltJ

possibly X malvace(poundrum and F moniliforme are an economically important cause of the damping-off of cotton seedlings The relashytive pathogenicity of a large number of the fungi that were isolated from diseased cotton seedlings in Oklahoma has been ascertained by Ray and McLaughlin (52)

One of the earliest treatments that was widely used in this country in an effort to increuse the emergence und survival of cottonseed wus thut of mixing the seed with moistened wood ashes This treutment removed much of the lint and mu~t have destroyed most of the fungus mycelia und spores on the seed coat After Atkinson (12) found that the anthracnose fungus was carried on the seed he demonstrated that it could be eliminated in some lots of seed by treutment with hot watetmiddot Other heut trcutments werE used by Duggar and Cuuthen (21) Barre (17) Lipscomb and (orley (~1) und Lehman (il) with the same objective Barre (16) found that delinting with sulfuric acid effectively eliminuted external infestation by G osJlti and reduced seedling losses thut resulted from infection by thiR fungus Further developments (18 11) in the use of acids for this purpose have led to the development of commetcial plants thaI deJint seed under the Brown-Streets (O) and Kcmgas patents (11) which use HSO bull and gaseous HOI respectively

Barre (10 and Duggar and Cauthen (28) were among the first to attempt to disinfect fuzzy cottonseed with such chemicals us copper sulfate mercuric chloride and formaldehyde lhese treutshyments wete only patmiddottiall~ eflective and eflective treatment with a fungicide became posHible onl~ when the organic ml~rcurials beshycame available later Initial studies of these chemicals (88 14 35 44 58 61 68 (0) had etablihecl by 1980 the effectiveness of ethyl mercuric chloride as a fungicide for the treatment of cottonshyseeds

In formation 011 the ptevalence and distributioll of the several puthogens infecting cotton eedlings that was obtained in COIlshy

current studies with those reported in this bulletin has already been published (i5 61) Summaries of some local data have also been published elsewhere (8 80 48 iLl) as have also data on related phases of these studies (15 Hi 17 65 66)

I~X PImiddotrOM 1middotNTt I PBOCEJ)IH E bull OIlIECIIVES ANn LOCONS OF Pl

Certain plantings of 1936-89 constituted (lne selies the A test The plantingfgt of the A test were made ptimati1y to ascertain the relative role of the pathogens infesting cottonseed and the facultative pathogens inhabiting the soil as causes of low seedling

bull

bull

emergence and survival Consequently the seed lots used were selected to provide wide variations in the degree of 5nfestation by the pathogens Colletotrichum fJo~sl7Jii and Fllwrium monUiforme Seed of these lots wetmiddotc treatltll with mercurial fungicides to deshy bull

7 COTTONSEED TREATMENT

bull termine the effect of these fungicides on the incidence of seedling diseases A second lleries of plantings the B test was initiated in 1988 to ascertain the relative agronomic value of fuzzy reshyginned and acid-delinted geed and also the most effective fungishycide that might be used for treatment of each kind of seed

Til these two series it was clearly demonstrated that seed treatshyment with fungicides reduced seedling losses caused by seedshyborne pathogen but the treatments used did not always eliminate extenic gceclling losse when conditions were favorable for seedshyling infection by soil-inhabiting pathogens (36 fj1) Hence a third series the e test was initiated later primarily to study the relatic protection that diflerent fungicides in varying dosages might afrOId cottOIl s([dlings against infection by both soil-inhabitshying and scpltI-bornepathogens In addition an effective fungicide as sought that would be less toxic to animals than the widely used but poisonous mercurials

Since the data from the three series of tests are most readilv ummarizecl separately the nsults from each test are dillcussed in separate sections ot this bulletill The nlrious localities at which plantings have been made and the soil charactEristics at these locations are ghen in table 1

bull ltd lot for the plantings of each 8eason were selected from

among t~pical lailable lots of planting seed on the basis of laborashytory tests TIl( iability of the seeds of the various lots (table 2) was ascerta i ned by germ ina ti ng in test tu bes on nonnutrient agar at 22 0 to 25 C (4) acid-delinted seeds that had been previously urflce-st(rilized by immersion for 2 minutes in a 025 percent solution or l[gCl in 50-lwrcent ethanol and then washed with terile water imnl(diatel )(fore they were placed on the agar Comparald( result were obtained when Cere-an-tleated fuzzy Metis were germinated in flats of steamed sand in th~ greenhouse exclpt fo lot n-F Th(se methods of ascertaining dability did not lllHs indicat~ accurateh thE relative vitalit of the serds of t1w nrious lots 01 their al)il1ty to produce seedlings in the Held sintl lot of the same dabilit produced greatly different pt)(pntqps of plants in certairl plantings tolw discugtsed later D(linted selds from which fungi were obtained are reported as internnllr infpcted (table 2) lnfe~tation of the seeds by paUlOshy~~n- was aSClrtiliIHd by glrminaiing ul1tnated fuzzy seed under -imilar lton(itiollS Thl~ 1111m)pr of healthy 8eedlings per 100 eld planted are )awd on Sl~(t1lil1g c()unt~ made 2 w(eks after the planting of the (1( in the ~illld cultures (table 2)

bull Tlw sled lots for a g-inl1 hst were asembled at one location

thoroug-hly mixed and rtquisiie portions were taken for the slpral tnatments The chemic-als u~ed for seed treatment were applild as dusts in a rotating lJarrel mix(r in which the duration of treatm(lt was generally standardized at 60 revolutions After

8 TECHNICAL BULLETIN 1025 U S DEPT 01lt AGRICUIJTURE

TABLE l-Locations at which ezperimental plantings were made in the several States and soil types at each location

Location Code I Soil type pH

Ar~ IMananna ___________ Ak-I __ __ Lintonia silt loam __ _ _ _ ___ _ 60

Gooflria Auburn _____ bullbullbull _ _ Ga-L _ _ ___ Cecil sandy loam __ bull __ bull ___ _ 60 Experiment ____ bull ___ _ Ga-2 ________ bull __ do ____________ _ bullbull _bullbullbull _____ 62 Hawkinsville _____ bull __ Ga-a ____ bull ___ bullbullbulldo_ ___________ bull ____ _____ a6

Louisiana Baton Rouge __ bullbullbull __ bull La-I bullbullbullbullbull Olivier lilt loam bull __ ___ bull __ _ 56Saint Joseph_ La-2_ ____ Sharkey silty clay loam bullbull _ ____ _ 70

MissilllippiHolly Serings _____ bullbull __ 1 Ms-4 ___ Grenada Kilt loam ____ bullbull ________ 57 Poplarvtlle_______ bull 1 Ms-L bullbullbull __ Ruston sandy loam __ bull __ _ 58 State College _ ___ bullJ MK-2 bullbullbull Catalpll 2 sandy loam _bullbull _ _ ___ 1 68 Stonevill~_ -I Ms-~ __ - Sarpy S very fine sand _________ bullbullbull 65 West Pomt_ ____ MII-D bullbullbullbullbullIHouston c1ay bull ___ bullbull _bullbull _ 80

I North Carolina I I

Goldsboro _ bull NC-3bull _ Norfolk Kandy loam_ bull _ _ bullbullbull Nashville __ bull bull NC-L do _ _ 68 Raleigh _ _ j NC-4__ Cecil fine sandy loam 68 Rocky Mount bull __INC-2 bull Norfolk sandy loam__ 64 State3ville __ _ _ NC--5__ Cecil fine sandy loam __

Oklahoma I Perkins bullbull _ j Ok-I _ _ I Canadian Iandy loam

I 61

South Carolina II Chester _ bull SC-4 bullbull _I Appling Illndy loam 52 Clemson _- SC-L _bullbull 1 Cecil sandy loam _ _ 54 Florence bull I~q-- - Dunbar sandy loam bull __ bull 54 Jefferson S0-8 Lakeland fine sand ___ 56 KathwoOlL SC-l bull I Cahaba fine Iandy loam _I 58 Pontiac bull bull ~C~_ _I Norfolk sandy loam ___ - - 1 50 Smoaks - - SC 6 _ _ Blanton fine Iand ______ bull i 56 Woodruff _ bull SCmiddot7 _bull Cecil sandy loam _ bull I 54

Texas iCollege Station _ ~t rx-1~~ ~ j Lufkin fine sandy loam 50Temple__ -J Tx-2bull Houlton black clay ifI

Tennesse Jackson Tn-2 i Lintonia silt loam _ _ _ 55Knoxville _ Tn-I Decatur Ii1ty clay loam 55

Virginia Holland_____ Va I Onllow sandy loam _ j6

1 Planting locations will be refcrJed to by this code in text to conserve spac( When more thaIj one planting in a season has been made at the same location the successive plantings Ilrc referred to as a b c and d

bull

bull

Name ulled at time the experiments were conducted With recent revisiolls

in soil classification this soil is probably Verona 1I Name u3ed at time the experiments were conducted With recent revhlions

in soil classification this soil is probably Bosket bull

9

bull

bull

bull

COTTONSEED TREATMENT

TA8LE 2-Characteristics of the lots of seed used in the A test 1936-99

Seedling emergence 8i per- r---shyr-I centage of seeds planted Internal

~ _____ ~_ __~_ _0 ~I infection State Code U d d Acid- I Fungi infesting of acidshy of

ntreate see s delinted untreated seeds I delinted origin an steamed sand Reeds in I seeds I - testshy

i Total IHealthy tubes I I~-6--1A-99-2~--_I--- 47 90 -C-g--F-m-__-_-_-_-__-_--_j-F-m--C-g-(-6)-a- -s-c-

36-81--- 69 40 85 Cg Iltm_~_ ______ Fm Cg (5) __ S C 36-B2 t 87 8 90 Fm____ bullbull _______________ S C 136-C---1 i5 45 89 Cg Fm ________ bullbull Cg (9) ______ S C 36-0___ 70 I) 86 Cg Fm ______ bull ___ Fm Cg (33)_ S c 36-E ____1 53 34 60 Cg Fm _________ Cg (6) ___ bull __ S C 36-F_-- 54 20 57 Cg Fm__________ Fm Cg (15)_ S C 36-G __ bullbull 50 31 84 Cg Fm__________ Cg (7) ______ S C

19$7 37-A __ _1 91 35 91 Cg Fm ___________________ bull ___ Ala 37-B1_ 80 43 88 Cg Fm__________ Cg (4) ______ Ga 37-B2 t-l 95 95 96 Fm ___________________________ S C 37-C __ _ 72 29 85 Cg Fm ____________ bull __________ Miss

f37-0__ _ 62 52 81 ICgFm _______bull _ Cg (1)------ Missa7-E- __1 69 42 78 Cg Fm__________ Cg (3) ______ S C 3i-F____ 40 40 24 Fm Xm ______________________ Okla 37-G __ 67 67 82 Fm______________ _ ________ Okla 37-H _i 79 59 80 l Cg Fm__________ Cg (2) __ __ N C

18 I I38-A __j 54 50 90 I Fm Rn ___ bull _______ bull _____ bullbull _ __ Calif 38-B 6__ 35 33 72 I Fm Rn Xm _____ ------------ Okla38-C __ l 80 22 84 Cg Fm ______ bull ___ Cg (3) ______ S C 38-0L __ 72 14 80 Cg Fm __________ Cg (4) ______ S C 38-02 1bullbull j 77 75 88 Fm ______ bull____________________ S C 38-EL 66 17 82 Cg Fm ___ bull ______ Cg (4) ______ S C 38-E2 __ 1 80 70 81 Cg Fm________ -- _ _________ S C 38-F___ l is 56 90 Cg Fm _________ Cg (2)_ ___ NC

1939 I ~t~==~ ~ ~~ ~F~pmiddotRn~-xniI-Xril~ gk~39-Cl__ 66 58 90 Cg Fm __ bull____ __ Cg______ bull ___ N C a9-C_ 1_ 90 90 90 I F N C 39-0bull 71 18 91 1 C~-F-R__~~nfi(10)--= SC 39-E ___ i 54 37 90 ICg Fm Rn ______ 1 Cg (9) ______ Miss 39-F __ 1 52 28 i3 Cg Fm ____ bull _____ ____________ Ga

39~~__ ~~ _ 37 ____~~_J~m~n Fsp_- __ ) bullbull __ _ _ _ _ _ _ Tex

t The several species of fungi are indicated as follows Cg = Colletotrichum gossypii Fm = Fllsarium11l1l1liliorme Fsp = FU8arium spp Rn=Rhizopus tligriCIJIIS Xm = XallthomOllaH maivacearllllt

~ Individual lots of seed are designated by the letter or letter and numeral following the number used to designate the year in which it was planted

1 Number of fleedlingll obtained from 100 acid-delinted seeds that were infected by C gossYllii are indicated by numbers in parentheses

bull Lots with 2 after the designating letter are the somiddotcalled 2-year-old seed or seed from next to the last crop preceding the year in which used a11d are of the lIame variety as the preceding lot of 1-year-old seed designated by the same letter and I which was usually grown in the same locality

54-year-old seed II ayear-old seed

10 TECH~ICAT BULJI~TINI025 U s D1wr OF AGHlCUrrUlm

treatment the sublots were divided into the requisite amounts for shipment to the cooperators Generally all treatments were made bull during the last 2 weeks in March while the individual field plantshyings were macle from the first week in April to the first week in May

The acid-delinted seed used in the experiments in 1936 1937 1940 and 1942 were delinted with concentrated sulfuric acid then washed over a sieve with a stream of water and finally immersed for 3 minutes in water containing an excess of CaCO The seed were again washed to remove the adhering carbonate and then dried on a wire sueen at about 25 C for not less than 24 hours before bagging rrhe acid-delinted seed used in the B tests of 1938 and 1939 were prepared by essentially the same method except for the omission of CaCO The delinted seed used in 1941 were prepaled at a commercial acid-delinting plantl) The seed after delinting were sepalatecl into two fractions the floaters and sinkshyers on the bashl of their specific gravity in comparison to that of waiel Pheil characteristics are given in the description of the seed lots lIsed ill th( B test of 1941 (see table 9) For comparison with this method of dclinting Hced delinted in the laboratory was included in foicvelal plantings

The reg-inned 01 machine-delinted sublots wcre preparcd at various gins 01 oil mills and varying quantities of lint were removed The details are given in connection with the description of seed lIsed each ~eal in the B test bull

PIOT TECIINIQUE

Replicated plotH fully randomized to permit analysis of the data by the anal~sis of variance method were used in all plantshyings The method of planting Iate of seeding and final spacing of the plants were left to the judgment of the individual cooperashywIs Generally the handling of plots approximated the general farm pJactice of the region in which thc plantings were made The several methods of planting ued ranged from hand dropping a definite number of seedH at a predetermined spacing to the use of animal-drawn onc-row plantels When planters were used the rate of seeding was calculated from the weight of the seed planted Regardless of efforts to calibnlte the planters to distribshyute about 10 Heed per foot in most plantings there were differshyclces as great aH 25 percent in the rate of seeding of the several lots of seed used in the same planting These differences were directly associated with the amount of lint on the seed However the differences in the lite of se(ling between the untreated and treated seed of the same lot generally did not exceed 3 percent a diffelence small enough to permit relatively accurate comparishysons of the effect of treatment in field plantings

r Cottonseed Dclinting COlp inc B1ufT Alk bull

11

bull

bull

COTTONSEED TREATMENT

The statistical analysis for most of the plantings in which mechanical planters were used are based on 4 replications of apshyproximately 500 seeds ill 50-foot rows However 100-foot rows planted at a rate of about 10 seeds per foot were used in certain plantings of the B test In the Oklahoma and Tennessee plantings in which the seed were dropped by hand a smaller number of seeds usually about 100 were planted in each replication Since in these plantings a definite number of seeds were planted the accuracy that was possible in the percentage of emergence calcushylations largely compensated fOI the smaller number of seeds planted as compared to the plantings in which mechanical planters were used All data on seedling emergence and survival are reshyported on the basis of 100 seedsu although as indicated the number of iced planted varied from 100 to 1000

C()LIEltTIO~ ~I) I~TEHIHEIATIO~ or DAIA

Because of the impotmiddottance of h~1ing companlble data from all locations on seedling emergence and survival at the time of thinshyning the following criteria were adopted for the classification of seedlings in making counts

1 EliltIYcc lind tellllhll-To include all seedlings that have raised their cotyledons abov( (free flom) the soil and have alleast one nOlllally expanded cotyledoll flce of the seed (oat SlIch geedlingR should be 1I0lmal ill appenlllllCC and not so badly disca~ed as to pn~clude survival

2 Emeryed nllli disllIscd-Seedlings of which lhe cotyledon hnve emelged from the soil reganless of whethel they are enclosed ill 01 free of the seed coat but at the time of the count arc either dead 01 so hadly (iHeasc( as to preclude survival as llIay be indicated by willing or abscnce of normal cotyledons

3 Partially c1IwJyed-Seedlings with any part showink above lhe soil bllt inslIfficiently developed to ascertain the probability of normal healthy emershygence

In actual practice it was found very difficult to obtain counts of claHses 2 and 3 that would be of value fOl statistical analysis Consequently all analyses reported in this bulletin with a few exceptions to be noted later are based on the counts of the healthy emerged seedlings

]n all plantings an eftort was made to make a seedling count at the time of thinning or at a corresponding stage of seedling deshyvelopment in those plantings that were not thinned At thi- time about tl weeks after planting most plants had ftom three to fiv~ true leaves and there was little likelihood of fLllmiddotther losses from seedling diseases This count referred to as the final seedling count was used to calculate the percentage of surviving seedlings

HAil nlllllbtmiddotrs given in the tables to show seedling emelgcnce and sLlrviv~d COllsClluently arc pelcentages 10 avoid confusion betw(len the sev(lJal senses in which pcrc()nt mijht be lIsed all diflelenccs delived from the subtraction of two percentage arc called numerical differences increases 01 decreases while percentage is used to refer to the relalive Hiz( of two cnuIg-enccs eg- when the emcrgcnce of the untreated seed was 40 percent and that of the treated seed 60 percnt the nUllIerical difference in elllergence was 20 percent but the percentage increase in elllergence for treatment was 50 percent

3 COTTONSEED TREATMENT

GENERAl SUMMARY

The increa~es in seedling emergence seedling survival and plant tands that resulted from the treatment of cottonseed with an effective fungicide were greatest for fuzzy seed that were infested by the anthracnaso furgus Colletotrichwm goss1fpii when soil condition~ and temperature were favorable for seedling infection by thiH fungus Large increases were also obtainHt with several lots of fuzzy seed that were infested by Rhizopus nigricnns Treatshyment of lots of fuzzy seed of good viability and not infested by either of the aboe fungi generally resulted in only small increases in seedling emergence and survival even when the percentage of seedling emergence was low Treatment of lots of low viability usually resulted in larger increases than did the treatment of lots of higher iability when thf lots were comparable in other reshyspects The increa-es that resulted from seed treatment regardless of the characteristics of the lot of seed tended to be larger in early plantings in which emergence was orten delayed by cool rainy weather than in later plantings when weather conditions were uStl~llly more favora e for rapid seedling emergence and growth

The more cfrectie fungicides used in these tests did not always increase seedling emergence and prevent damping-off when condishytions were fworable 101 infection of the seedlings by soil-inhabit shying pathogens which indicates that they acted lalgely as seed di~inf(ctlnts rather than as seedling protectants However in ie(ral pladings in which two or more seedling counts were made the treatment of seed lots not infested by C gossypi-i did result in reduced damping-off as well as a lesseuror number of lesions on the hypocotyls of surviving seedlings The instances in which seed treatment failed to increase emergence were more frequent on the hea soil of the Jfississippi Delta than on lighter and better cI ra i ned soils Isolations from diseased seedl i ngs obtained from these plantings showed that bacteria Fl)coiwn lIlollilifornle other fuaria Rhioclollia ()iali an(1 nliOtlS other soil-inhabiting pathogen had inf(cterJ thp seeds and seedlings

pecial tlsts of the ((fect of tJpclting cottonseed with organic I1wrcurial that diffpr(d gnatly in such characteristics as water -olubility and volatility in(icatNj that the cffectieness of this trlatm~~nt lt1 not HSiociatld with a definite physical-chemical property It n shown however that relatively large amounts of CQm para thely Olil tile btl t Iionolu ble mercu rial were less toxic to cotton seedlings a- indicated hy emergence of eed treated with them the1 les olalile and more soluble mercurials Although relathely nonolatilc mercurials efIectiely eliminated Reed-borne pathogens rendts with other chemicals geemed to Rhow that a funshygicide must be olatile to some degree if it is to be an effective chemical for the treatment of fuzzy and Ieginned seed Volatile and nOlwolatile fungicides wer( equally effecthe for the heatment of add-delinted cottons(((1

bull

4 TECHNICAL BULLETIN 1025 U S DEPT OF AGRICUITURE

Seed treatment increased final stands to a much smaller extent than it increased seedling emergence and survival This was bull largely accounted for by the fact that a much heavier rate of seeding was used than was necessary to produce a stand of plants in most plantings Plant-stand counts were made after thinning and again at the time of picking in a number of plantings Losses during this interval averaged slightly less than 10 percent but were occasionally greater than 20 percent Analysis of the data showed no correlation between after-thinning losses and treatshyment or characteristics of the seed Apparently the seed-borne pathogens had no direct relation to the agents that kill cotton plants after the seedling stage

In most plantings seed treatment produced no increases or only small increases in yield This should logically be expected from the generally small differences in residual stand after thinning beshytween the untreated and treated seed However occasional inshycreases in yield as great as 20 percent were obtained and in the A tests of 1936-39 the mean increases for lots infested by C g08~ypii generally ranged from 7 to 12 percent The failure of seed treatment to produce increased yields in every planting does not invalidate the general belief that the treatment of cottonseed is a good practice since the usual small increases and occasional larger increases in yield fully compensate for the expense and inshyconveniences associated with seed treatment

Seed treatment also may be considered good insurance against the low yields usually associated with replanting in seasons when untreated seed will not produce an adequate stand at the usual bull time of planting The results obtained in these plantings have demonstrated that seed treated with an effective fungicide will generally produce a larger and more uniform stand of plants than untreated seed Consequently seed treatment may be used as a means of obtaining an adequate stand of p1ants for optimal yields from a smaller number of seeds

The response to treatment of reginned seed (seed from which part of the linters was removed in a second ginning) was freshyquently different from that of fuzzy seed from the same lot In some instances the emergence of the untreated reginned seed was much greater than that of the untreated fuzzy seed and conseshyquently the response of reginned seed to treatment was much smaller It is presumed that these differences in some manner were associated with a reduction in the amount of infective myceliti and spores of C gossypii during reginning Observations on the temperature of the seed mass during reginning showed that the maximal temperature attained wes not high enough to kill the bull anthracnose fungus

With other lots of seed the emergence of the untreated reginned

bull

seed was about the same or slightly lower than that of the correshysponding untreated fuzzy seed and the seed treatment resulted in comparable increases for both Heavily reginned seed tended to

5 COTTONSEED TREATMENT

bull give a larger response to treatment than less heavily reginned seed Since scarification of the seed coat tended to increase with the amount of lint removed it is likely that the high response of certain lots of reginned seed to treatment was in some manner associated with the scarification of the seed coat in reginning

Treatment of acid-delinted seed with fungicides generally reshysulted in only small increases in seedling emergence although there were large increases in several plantings in which emergence was delayed by cool rainy weather The testae of acid-delinted seed are very slisceptible to invasion by saprophytic fungi and when emergence is delayed such fungi may kill the young seedshylings Although the treatment of acid-delinted seed with a fungishycide usually produced only small increases in seedling emergence treatment appears to be fully justified because of the occasional large increases in emergence

Regardless of the occasional instances in which fuzzy seed tended to emerge more slowly than reginned and delinted seed no superiority in ability to produce stands of plants or yields was shown for reginned delinted or water-graded delinted seed as compared to that of fuzzy seed when these three kinds of seed were treated with an effective fungicide The results of these plantings would indicate that any advantage that one of these types of seed may have in comparison to another must lie in some convenience related to agronomic practice

HEVIEW OF L1TERATFHE

Previollsly published observations dating from those of Atkinshy)on (UU)1 have ascribed damping-off to Rhizoctonia solani Kuehn (36 gt2 61) CollelotrichllnL gossypii South4 (1 15 32) Fll-sariwn vasinfectum Atk (gt6) other fusaria (51 5n Scleroshytililit rolj-sii Sacco (16) Pythiwn ultimum Trow (2) Phymatoshytrichwn omniVOium (Shear) Duggar (53) and Thielaviopsis basicola (Berk) Ferraris (50) It has been supposed that F-U8arshyium moniliorlHe Sheldon also might be the cause of damping-off although there arl no published observations to this effect This funguil however has been definitely shown to invade cotton roots (61) The possibility of seedling infection arising from seed-borne C gossypii was first ciemolutrated by Atkinson (11) and later emphasized by Barre (Vi) and Edg-erton (24) Experiments by Rolfs (55) and by lltaulwetter (27) have shown that Xanthomona4 malvacealuln (E F Sm) Dowson also may be seed-borne F vasshyinfectum has been reported as a seed-borne disease (25 56 60) Many other fungi have been ifiolated from the interior of cottonshyseeds (22) There is still some question however as to whether any of the seed-borne bacteria and fungi except C gossypii and

I Italic numbers in parentheses refer to Literature Cited p 110 I This name is used for the anthracnose fungus in this paper instead of

Glomrella gOllsYJJii (South) Edg becliuse of the unltcrtuinty of the identity of C gOllllllpii with the Glomrrtlilt isoilited by Edgerton (57)bull

6 TECH~ICAL BULBTIN 102 tT S DEPT OF AGRICULTURJltJ

possibly X malvace(poundrum and F moniliforme are an economically important cause of the damping-off of cotton seedlings The relashytive pathogenicity of a large number of the fungi that were isolated from diseased cotton seedlings in Oklahoma has been ascertained by Ray and McLaughlin (52)

One of the earliest treatments that was widely used in this country in an effort to increuse the emergence und survival of cottonseed wus thut of mixing the seed with moistened wood ashes This treutment removed much of the lint and mu~t have destroyed most of the fungus mycelia und spores on the seed coat After Atkinson (12) found that the anthracnose fungus was carried on the seed he demonstrated that it could be eliminated in some lots of seed by treutment with hot watetmiddot Other heut trcutments werE used by Duggar and Cuuthen (21) Barre (17) Lipscomb and (orley (~1) und Lehman (il) with the same objective Barre (16) found that delinting with sulfuric acid effectively eliminuted external infestation by G osJlti and reduced seedling losses thut resulted from infection by thiR fungus Further developments (18 11) in the use of acids for this purpose have led to the development of commetcial plants thaI deJint seed under the Brown-Streets (O) and Kcmgas patents (11) which use HSO bull and gaseous HOI respectively

Barre (10 and Duggar and Cauthen (28) were among the first to attempt to disinfect fuzzy cottonseed with such chemicals us copper sulfate mercuric chloride and formaldehyde lhese treutshyments wete only patmiddottiall~ eflective and eflective treatment with a fungicide became posHible onl~ when the organic ml~rcurials beshycame available later Initial studies of these chemicals (88 14 35 44 58 61 68 (0) had etablihecl by 1980 the effectiveness of ethyl mercuric chloride as a fungicide for the treatment of cottonshyseeds

In formation 011 the ptevalence and distributioll of the several puthogens infecting cotton eedlings that was obtained in COIlshy

current studies with those reported in this bulletin has already been published (i5 61) Summaries of some local data have also been published elsewhere (8 80 48 iLl) as have also data on related phases of these studies (15 Hi 17 65 66)

I~X PImiddotrOM 1middotNTt I PBOCEJ)IH E bull OIlIECIIVES ANn LOCONS OF Pl

Certain plantings of 1936-89 constituted (lne selies the A test The plantingfgt of the A test were made ptimati1y to ascertain the relative role of the pathogens infesting cottonseed and the facultative pathogens inhabiting the soil as causes of low seedling

bull

bull

emergence and survival Consequently the seed lots used were selected to provide wide variations in the degree of 5nfestation by the pathogens Colletotrichum fJo~sl7Jii and Fllwrium monUiforme Seed of these lots wetmiddotc treatltll with mercurial fungicides to deshy bull

7 COTTONSEED TREATMENT

bull termine the effect of these fungicides on the incidence of seedling diseases A second lleries of plantings the B test was initiated in 1988 to ascertain the relative agronomic value of fuzzy reshyginned and acid-delinted geed and also the most effective fungishycide that might be used for treatment of each kind of seed

Til these two series it was clearly demonstrated that seed treatshyment with fungicides reduced seedling losses caused by seedshyborne pathogen but the treatments used did not always eliminate extenic gceclling losse when conditions were favorable for seedshyling infection by soil-inhabiting pathogens (36 fj1) Hence a third series the e test was initiated later primarily to study the relatic protection that diflerent fungicides in varying dosages might afrOId cottOIl s([dlings against infection by both soil-inhabitshying and scpltI-bornepathogens In addition an effective fungicide as sought that would be less toxic to animals than the widely used but poisonous mercurials

Since the data from the three series of tests are most readilv ummarizecl separately the nsults from each test are dillcussed in separate sections ot this bulletill The nlrious localities at which plantings have been made and the soil charactEristics at these locations are ghen in table 1

bull ltd lot for the plantings of each 8eason were selected from

among t~pical lailable lots of planting seed on the basis of laborashytory tests TIl( iability of the seeds of the various lots (table 2) was ascerta i ned by germ ina ti ng in test tu bes on nonnutrient agar at 22 0 to 25 C (4) acid-delinted seeds that had been previously urflce-st(rilized by immersion for 2 minutes in a 025 percent solution or l[gCl in 50-lwrcent ethanol and then washed with terile water imnl(diatel )(fore they were placed on the agar Comparald( result were obtained when Cere-an-tleated fuzzy Metis were germinated in flats of steamed sand in th~ greenhouse exclpt fo lot n-F Th(se methods of ascertaining dability did not lllHs indicat~ accurateh thE relative vitalit of the serds of t1w nrious lots 01 their al)il1ty to produce seedlings in the Held sintl lot of the same dabilit produced greatly different pt)(pntqps of plants in certairl plantings tolw discugtsed later D(linted selds from which fungi were obtained are reported as internnllr infpcted (table 2) lnfe~tation of the seeds by paUlOshy~~n- was aSClrtiliIHd by glrminaiing ul1tnated fuzzy seed under -imilar lton(itiollS Thl~ 1111m)pr of healthy 8eedlings per 100 eld planted are )awd on Sl~(t1lil1g c()unt~ made 2 w(eks after the planting of the (1( in the ~illld cultures (table 2)

bull Tlw sled lots for a g-inl1 hst were asembled at one location

thoroug-hly mixed and rtquisiie portions were taken for the slpral tnatments The chemic-als u~ed for seed treatment were applild as dusts in a rotating lJarrel mix(r in which the duration of treatm(lt was generally standardized at 60 revolutions After

8 TECHNICAL BULLETIN 1025 U S DEPT 01lt AGRICUIJTURE

TABLE l-Locations at which ezperimental plantings were made in the several States and soil types at each location

Location Code I Soil type pH

Ar~ IMananna ___________ Ak-I __ __ Lintonia silt loam __ _ _ _ ___ _ 60

Gooflria Auburn _____ bullbullbull _ _ Ga-L _ _ ___ Cecil sandy loam __ bull __ bull ___ _ 60 Experiment ____ bull ___ _ Ga-2 ________ bull __ do ____________ _ bullbull _bullbullbull _____ 62 Hawkinsville _____ bull __ Ga-a ____ bull ___ bullbullbulldo_ ___________ bull ____ _____ a6

Louisiana Baton Rouge __ bullbullbull __ bull La-I bullbullbullbullbull Olivier lilt loam bull __ ___ bull __ _ 56Saint Joseph_ La-2_ ____ Sharkey silty clay loam bullbull _ ____ _ 70

MissilllippiHolly Serings _____ bullbull __ 1 Ms-4 ___ Grenada Kilt loam ____ bullbull ________ 57 Poplarvtlle_______ bull 1 Ms-L bullbullbull __ Ruston sandy loam __ bull __ _ 58 State College _ ___ bullJ MK-2 bullbullbull Catalpll 2 sandy loam _bullbull _ _ ___ 1 68 Stonevill~_ -I Ms-~ __ - Sarpy S very fine sand _________ bullbullbull 65 West Pomt_ ____ MII-D bullbullbullbullbullIHouston c1ay bull ___ bullbull _bullbull _ 80

I North Carolina I I

Goldsboro _ bull NC-3bull _ Norfolk Kandy loam_ bull _ _ bullbullbull Nashville __ bull bull NC-L do _ _ 68 Raleigh _ _ j NC-4__ Cecil fine sandy loam 68 Rocky Mount bull __INC-2 bull Norfolk sandy loam__ 64 State3ville __ _ _ NC--5__ Cecil fine sandy loam __

Oklahoma I Perkins bullbull _ j Ok-I _ _ I Canadian Iandy loam

I 61

South Carolina II Chester _ bull SC-4 bullbull _I Appling Illndy loam 52 Clemson _- SC-L _bullbull 1 Cecil sandy loam _ _ 54 Florence bull I~q-- - Dunbar sandy loam bull __ bull 54 Jefferson S0-8 Lakeland fine sand ___ 56 KathwoOlL SC-l bull I Cahaba fine Iandy loam _I 58 Pontiac bull bull ~C~_ _I Norfolk sandy loam ___ - - 1 50 Smoaks - - SC 6 _ _ Blanton fine Iand ______ bull i 56 Woodruff _ bull SCmiddot7 _bull Cecil sandy loam _ bull I 54

Texas iCollege Station _ ~t rx-1~~ ~ j Lufkin fine sandy loam 50Temple__ -J Tx-2bull Houlton black clay ifI

Tennesse Jackson Tn-2 i Lintonia silt loam _ _ _ 55Knoxville _ Tn-I Decatur Ii1ty clay loam 55

Virginia Holland_____ Va I Onllow sandy loam _ j6

1 Planting locations will be refcrJed to by this code in text to conserve spac( When more thaIj one planting in a season has been made at the same location the successive plantings Ilrc referred to as a b c and d

bull

bull

Name ulled at time the experiments were conducted With recent revisiolls

in soil classification this soil is probably Verona 1I Name u3ed at time the experiments were conducted With recent revhlions

in soil classification this soil is probably Bosket bull

9

bull

bull

bull

COTTONSEED TREATMENT

TA8LE 2-Characteristics of the lots of seed used in the A test 1936-99

Seedling emergence 8i per- r---shyr-I centage of seeds planted Internal

~ _____ ~_ __~_ _0 ~I infection State Code U d d Acid- I Fungi infesting of acidshy of

ntreate see s delinted untreated seeds I delinted origin an steamed sand Reeds in I seeds I - testshy

i Total IHealthy tubes I I~-6--1A-99-2~--_I--- 47 90 -C-g--F-m-__-_-_-_-__-_--_j-F-m--C-g-(-6)-a- -s-c-

36-81--- 69 40 85 Cg Iltm_~_ ______ Fm Cg (5) __ S C 36-B2 t 87 8 90 Fm____ bullbull _______________ S C 136-C---1 i5 45 89 Cg Fm ________ bullbull Cg (9) ______ S C 36-0___ 70 I) 86 Cg Fm ______ bull ___ Fm Cg (33)_ S c 36-E ____1 53 34 60 Cg Fm _________ Cg (6) ___ bull __ S C 36-F_-- 54 20 57 Cg Fm__________ Fm Cg (15)_ S C 36-G __ bullbull 50 31 84 Cg Fm__________ Cg (7) ______ S C

19$7 37-A __ _1 91 35 91 Cg Fm ___________________ bull ___ Ala 37-B1_ 80 43 88 Cg Fm__________ Cg (4) ______ Ga 37-B2 t-l 95 95 96 Fm ___________________________ S C 37-C __ _ 72 29 85 Cg Fm ____________ bull __________ Miss

f37-0__ _ 62 52 81 ICgFm _______bull _ Cg (1)------ Missa7-E- __1 69 42 78 Cg Fm__________ Cg (3) ______ S C 3i-F____ 40 40 24 Fm Xm ______________________ Okla 37-G __ 67 67 82 Fm______________ _ ________ Okla 37-H _i 79 59 80 l Cg Fm__________ Cg (2) __ __ N C

18 I I38-A __j 54 50 90 I Fm Rn ___ bull _______ bull _____ bullbull _ __ Calif 38-B 6__ 35 33 72 I Fm Rn Xm _____ ------------ Okla38-C __ l 80 22 84 Cg Fm ______ bull ___ Cg (3) ______ S C 38-0L __ 72 14 80 Cg Fm __________ Cg (4) ______ S C 38-02 1bullbull j 77 75 88 Fm ______ bull____________________ S C 38-EL 66 17 82 Cg Fm ___ bull ______ Cg (4) ______ S C 38-E2 __ 1 80 70 81 Cg Fm________ -- _ _________ S C 38-F___ l is 56 90 Cg Fm _________ Cg (2)_ ___ NC

1939 I ~t~==~ ~ ~~ ~F~pmiddotRn~-xniI-Xril~ gk~39-Cl__ 66 58 90 Cg Fm __ bull____ __ Cg______ bull ___ N C a9-C_ 1_ 90 90 90 I F N C 39-0bull 71 18 91 1 C~-F-R__~~nfi(10)--= SC 39-E ___ i 54 37 90 ICg Fm Rn ______ 1 Cg (9) ______ Miss 39-F __ 1 52 28 i3 Cg Fm ____ bull _____ ____________ Ga

39~~__ ~~ _ 37 ____~~_J~m~n Fsp_- __ ) bullbull __ _ _ _ _ _ _ Tex

t The several species of fungi are indicated as follows Cg = Colletotrichum gossypii Fm = Fllsarium11l1l1liliorme Fsp = FU8arium spp Rn=Rhizopus tligriCIJIIS Xm = XallthomOllaH maivacearllllt

~ Individual lots of seed are designated by the letter or letter and numeral following the number used to designate the year in which it was planted

1 Number of fleedlingll obtained from 100 acid-delinted seeds that were infected by C gossYllii are indicated by numbers in parentheses

bull Lots with 2 after the designating letter are the somiddotcalled 2-year-old seed or seed from next to the last crop preceding the year in which used a11d are of the lIame variety as the preceding lot of 1-year-old seed designated by the same letter and I which was usually grown in the same locality

54-year-old seed II ayear-old seed

10 TECH~ICAT BULJI~TINI025 U s D1wr OF AGHlCUrrUlm

treatment the sublots were divided into the requisite amounts for shipment to the cooperators Generally all treatments were made bull during the last 2 weeks in March while the individual field plantshyings were macle from the first week in April to the first week in May

The acid-delinted seed used in the experiments in 1936 1937 1940 and 1942 were delinted with concentrated sulfuric acid then washed over a sieve with a stream of water and finally immersed for 3 minutes in water containing an excess of CaCO The seed were again washed to remove the adhering carbonate and then dried on a wire sueen at about 25 C for not less than 24 hours before bagging rrhe acid-delinted seed used in the B tests of 1938 and 1939 were prepared by essentially the same method except for the omission of CaCO The delinted seed used in 1941 were prepaled at a commercial acid-delinting plantl) The seed after delinting were sepalatecl into two fractions the floaters and sinkshyers on the bashl of their specific gravity in comparison to that of waiel Pheil characteristics are given in the description of the seed lots lIsed ill th( B test of 1941 (see table 9) For comparison with this method of dclinting Hced delinted in the laboratory was included in foicvelal plantings

The reg-inned 01 machine-delinted sublots wcre preparcd at various gins 01 oil mills and varying quantities of lint were removed The details are given in connection with the description of seed lIsed each ~eal in the B test bull

PIOT TECIINIQUE

Replicated plotH fully randomized to permit analysis of the data by the anal~sis of variance method were used in all plantshyings The method of planting Iate of seeding and final spacing of the plants were left to the judgment of the individual cooperashywIs Generally the handling of plots approximated the general farm pJactice of the region in which thc plantings were made The several methods of planting ued ranged from hand dropping a definite number of seedH at a predetermined spacing to the use of animal-drawn onc-row plantels When planters were used the rate of seeding was calculated from the weight of the seed planted Regardless of efforts to calibnlte the planters to distribshyute about 10 Heed per foot in most plantings there were differshyclces as great aH 25 percent in the rate of seeding of the several lots of seed used in the same planting These differences were directly associated with the amount of lint on the seed However the differences in the lite of se(ling between the untreated and treated seed of the same lot generally did not exceed 3 percent a diffelence small enough to permit relatively accurate comparishysons of the effect of treatment in field plantings

r Cottonseed Dclinting COlp inc B1ufT Alk bull

11

bull

bull

COTTONSEED TREATMENT

The statistical analysis for most of the plantings in which mechanical planters were used are based on 4 replications of apshyproximately 500 seeds ill 50-foot rows However 100-foot rows planted at a rate of about 10 seeds per foot were used in certain plantings of the B test In the Oklahoma and Tennessee plantings in which the seed were dropped by hand a smaller number of seeds usually about 100 were planted in each replication Since in these plantings a definite number of seeds were planted the accuracy that was possible in the percentage of emergence calcushylations largely compensated fOI the smaller number of seeds planted as compared to the plantings in which mechanical planters were used All data on seedling emergence and survival are reshyported on the basis of 100 seedsu although as indicated the number of iced planted varied from 100 to 1000

C()LIEltTIO~ ~I) I~TEHIHEIATIO~ or DAIA

Because of the impotmiddottance of h~1ing companlble data from all locations on seedling emergence and survival at the time of thinshyning the following criteria were adopted for the classification of seedlings in making counts

1 EliltIYcc lind tellllhll-To include all seedlings that have raised their cotyledons abov( (free flom) the soil and have alleast one nOlllally expanded cotyledoll flce of the seed (oat SlIch geedlingR should be 1I0lmal ill appenlllllCC and not so badly disca~ed as to pn~clude survival

2 Emeryed nllli disllIscd-Seedlings of which lhe cotyledon hnve emelged from the soil reganless of whethel they are enclosed ill 01 free of the seed coat but at the time of the count arc either dead 01 so hadly (iHeasc( as to preclude survival as llIay be indicated by willing or abscnce of normal cotyledons

3 Partially c1IwJyed-Seedlings with any part showink above lhe soil bllt inslIfficiently developed to ascertain the probability of normal healthy emershygence

In actual practice it was found very difficult to obtain counts of claHses 2 and 3 that would be of value fOl statistical analysis Consequently all analyses reported in this bulletin with a few exceptions to be noted later are based on the counts of the healthy emerged seedlings

]n all plantings an eftort was made to make a seedling count at the time of thinning or at a corresponding stage of seedling deshyvelopment in those plantings that were not thinned At thi- time about tl weeks after planting most plants had ftom three to fiv~ true leaves and there was little likelihood of fLllmiddotther losses from seedling diseases This count referred to as the final seedling count was used to calculate the percentage of surviving seedlings

HAil nlllllbtmiddotrs given in the tables to show seedling emelgcnce and sLlrviv~d COllsClluently arc pelcentages 10 avoid confusion betw(len the sev(lJal senses in which pcrc()nt mijht be lIsed all diflelenccs delived from the subtraction of two percentage arc called numerical differences increases 01 decreases while percentage is used to refer to the relalive Hiz( of two cnuIg-enccs eg- when the emcrgcnce of the untreated seed was 40 percent and that of the treated seed 60 percnt the nUllIerical difference in elllergence was 20 percent but the percentage increase in elllergence for treatment was 50 percent

4 TECHNICAL BULLETIN 1025 U S DEPT OF AGRICUITURE

Seed treatment increased final stands to a much smaller extent than it increased seedling emergence and survival This was bull largely accounted for by the fact that a much heavier rate of seeding was used than was necessary to produce a stand of plants in most plantings Plant-stand counts were made after thinning and again at the time of picking in a number of plantings Losses during this interval averaged slightly less than 10 percent but were occasionally greater than 20 percent Analysis of the data showed no correlation between after-thinning losses and treatshyment or characteristics of the seed Apparently the seed-borne pathogens had no direct relation to the agents that kill cotton plants after the seedling stage

In most plantings seed treatment produced no increases or only small increases in yield This should logically be expected from the generally small differences in residual stand after thinning beshytween the untreated and treated seed However occasional inshycreases in yield as great as 20 percent were obtained and in the A tests of 1936-39 the mean increases for lots infested by C g08~ypii generally ranged from 7 to 12 percent The failure of seed treatment to produce increased yields in every planting does not invalidate the general belief that the treatment of cottonseed is a good practice since the usual small increases and occasional larger increases in yield fully compensate for the expense and inshyconveniences associated with seed treatment

Seed treatment also may be considered good insurance against the low yields usually associated with replanting in seasons when untreated seed will not produce an adequate stand at the usual bull time of planting The results obtained in these plantings have demonstrated that seed treated with an effective fungicide will generally produce a larger and more uniform stand of plants than untreated seed Consequently seed treatment may be used as a means of obtaining an adequate stand of p1ants for optimal yields from a smaller number of seeds

The response to treatment of reginned seed (seed from which part of the linters was removed in a second ginning) was freshyquently different from that of fuzzy seed from the same lot In some instances the emergence of the untreated reginned seed was much greater than that of the untreated fuzzy seed and conseshyquently the response of reginned seed to treatment was much smaller It is presumed that these differences in some manner were associated with a reduction in the amount of infective myceliti and spores of C gossypii during reginning Observations on the temperature of the seed mass during reginning showed that the maximal temperature attained wes not high enough to kill the bull anthracnose fungus

With other lots of seed the emergence of the untreated reginned

bull

seed was about the same or slightly lower than that of the correshysponding untreated fuzzy seed and the seed treatment resulted in comparable increases for both Heavily reginned seed tended to

5 COTTONSEED TREATMENT

bull give a larger response to treatment than less heavily reginned seed Since scarification of the seed coat tended to increase with the amount of lint removed it is likely that the high response of certain lots of reginned seed to treatment was in some manner associated with the scarification of the seed coat in reginning

Treatment of acid-delinted seed with fungicides generally reshysulted in only small increases in seedling emergence although there were large increases in several plantings in which emergence was delayed by cool rainy weather The testae of acid-delinted seed are very slisceptible to invasion by saprophytic fungi and when emergence is delayed such fungi may kill the young seedshylings Although the treatment of acid-delinted seed with a fungishycide usually produced only small increases in seedling emergence treatment appears to be fully justified because of the occasional large increases in emergence

Regardless of the occasional instances in which fuzzy seed tended to emerge more slowly than reginned and delinted seed no superiority in ability to produce stands of plants or yields was shown for reginned delinted or water-graded delinted seed as compared to that of fuzzy seed when these three kinds of seed were treated with an effective fungicide The results of these plantings would indicate that any advantage that one of these types of seed may have in comparison to another must lie in some convenience related to agronomic practice

HEVIEW OF L1TERATFHE

Previollsly published observations dating from those of Atkinshy)on (UU)1 have ascribed damping-off to Rhizoctonia solani Kuehn (36 gt2 61) CollelotrichllnL gossypii South4 (1 15 32) Fll-sariwn vasinfectum Atk (gt6) other fusaria (51 5n Scleroshytililit rolj-sii Sacco (16) Pythiwn ultimum Trow (2) Phymatoshytrichwn omniVOium (Shear) Duggar (53) and Thielaviopsis basicola (Berk) Ferraris (50) It has been supposed that F-U8arshyium moniliorlHe Sheldon also might be the cause of damping-off although there arl no published observations to this effect This funguil however has been definitely shown to invade cotton roots (61) The possibility of seedling infection arising from seed-borne C gossypii was first ciemolutrated by Atkinson (11) and later emphasized by Barre (Vi) and Edg-erton (24) Experiments by Rolfs (55) and by lltaulwetter (27) have shown that Xanthomona4 malvacealuln (E F Sm) Dowson also may be seed-borne F vasshyinfectum has been reported as a seed-borne disease (25 56 60) Many other fungi have been ifiolated from the interior of cottonshyseeds (22) There is still some question however as to whether any of the seed-borne bacteria and fungi except C gossypii and

I Italic numbers in parentheses refer to Literature Cited p 110 I This name is used for the anthracnose fungus in this paper instead of

Glomrella gOllsYJJii (South) Edg becliuse of the unltcrtuinty of the identity of C gOllllllpii with the Glomrrtlilt isoilited by Edgerton (57)bull

6 TECH~ICAL BULBTIN 102 tT S DEPT OF AGRICULTURJltJ

possibly X malvace(poundrum and F moniliforme are an economically important cause of the damping-off of cotton seedlings The relashytive pathogenicity of a large number of the fungi that were isolated from diseased cotton seedlings in Oklahoma has been ascertained by Ray and McLaughlin (52)

One of the earliest treatments that was widely used in this country in an effort to increuse the emergence und survival of cottonseed wus thut of mixing the seed with moistened wood ashes This treutment removed much of the lint and mu~t have destroyed most of the fungus mycelia und spores on the seed coat After Atkinson (12) found that the anthracnose fungus was carried on the seed he demonstrated that it could be eliminated in some lots of seed by treutment with hot watetmiddot Other heut trcutments werE used by Duggar and Cuuthen (21) Barre (17) Lipscomb and (orley (~1) und Lehman (il) with the same objective Barre (16) found that delinting with sulfuric acid effectively eliminuted external infestation by G osJlti and reduced seedling losses thut resulted from infection by thiR fungus Further developments (18 11) in the use of acids for this purpose have led to the development of commetcial plants thaI deJint seed under the Brown-Streets (O) and Kcmgas patents (11) which use HSO bull and gaseous HOI respectively

Barre (10 and Duggar and Cauthen (28) were among the first to attempt to disinfect fuzzy cottonseed with such chemicals us copper sulfate mercuric chloride and formaldehyde lhese treutshyments wete only patmiddottiall~ eflective and eflective treatment with a fungicide became posHible onl~ when the organic ml~rcurials beshycame available later Initial studies of these chemicals (88 14 35 44 58 61 68 (0) had etablihecl by 1980 the effectiveness of ethyl mercuric chloride as a fungicide for the treatment of cottonshyseeds

In formation 011 the ptevalence and distributioll of the several puthogens infecting cotton eedlings that was obtained in COIlshy

current studies with those reported in this bulletin has already been published (i5 61) Summaries of some local data have also been published elsewhere (8 80 48 iLl) as have also data on related phases of these studies (15 Hi 17 65 66)

I~X PImiddotrOM 1middotNTt I PBOCEJ)IH E bull OIlIECIIVES ANn LOCONS OF Pl

Certain plantings of 1936-89 constituted (lne selies the A test The plantingfgt of the A test were made ptimati1y to ascertain the relative role of the pathogens infesting cottonseed and the facultative pathogens inhabiting the soil as causes of low seedling

bull

bull

emergence and survival Consequently the seed lots used were selected to provide wide variations in the degree of 5nfestation by the pathogens Colletotrichum fJo~sl7Jii and Fllwrium monUiforme Seed of these lots wetmiddotc treatltll with mercurial fungicides to deshy bull

7 COTTONSEED TREATMENT

bull termine the effect of these fungicides on the incidence of seedling diseases A second lleries of plantings the B test was initiated in 1988 to ascertain the relative agronomic value of fuzzy reshyginned and acid-delinted geed and also the most effective fungishycide that might be used for treatment of each kind of seed

Til these two series it was clearly demonstrated that seed treatshyment with fungicides reduced seedling losses caused by seedshyborne pathogen but the treatments used did not always eliminate extenic gceclling losse when conditions were favorable for seedshyling infection by soil-inhabiting pathogens (36 fj1) Hence a third series the e test was initiated later primarily to study the relatic protection that diflerent fungicides in varying dosages might afrOId cottOIl s([dlings against infection by both soil-inhabitshying and scpltI-bornepathogens In addition an effective fungicide as sought that would be less toxic to animals than the widely used but poisonous mercurials

Since the data from the three series of tests are most readilv ummarizecl separately the nsults from each test are dillcussed in separate sections ot this bulletill The nlrious localities at which plantings have been made and the soil charactEristics at these locations are ghen in table 1

bull ltd lot for the plantings of each 8eason were selected from

among t~pical lailable lots of planting seed on the basis of laborashytory tests TIl( iability of the seeds of the various lots (table 2) was ascerta i ned by germ ina ti ng in test tu bes on nonnutrient agar at 22 0 to 25 C (4) acid-delinted seeds that had been previously urflce-st(rilized by immersion for 2 minutes in a 025 percent solution or l[gCl in 50-lwrcent ethanol and then washed with terile water imnl(diatel )(fore they were placed on the agar Comparald( result were obtained when Cere-an-tleated fuzzy Metis were germinated in flats of steamed sand in th~ greenhouse exclpt fo lot n-F Th(se methods of ascertaining dability did not lllHs indicat~ accurateh thE relative vitalit of the serds of t1w nrious lots 01 their al)il1ty to produce seedlings in the Held sintl lot of the same dabilit produced greatly different pt)(pntqps of plants in certairl plantings tolw discugtsed later D(linted selds from which fungi were obtained are reported as internnllr infpcted (table 2) lnfe~tation of the seeds by paUlOshy~~n- was aSClrtiliIHd by glrminaiing ul1tnated fuzzy seed under -imilar lton(itiollS Thl~ 1111m)pr of healthy 8eedlings per 100 eld planted are )awd on Sl~(t1lil1g c()unt~ made 2 w(eks after the planting of the (1( in the ~illld cultures (table 2)

bull Tlw sled lots for a g-inl1 hst were asembled at one location

thoroug-hly mixed and rtquisiie portions were taken for the slpral tnatments The chemic-als u~ed for seed treatment were applild as dusts in a rotating lJarrel mix(r in which the duration of treatm(lt was generally standardized at 60 revolutions After

8 TECHNICAL BULLETIN 1025 U S DEPT 01lt AGRICUIJTURE

TABLE l-Locations at which ezperimental plantings were made in the several States and soil types at each location

Location Code I Soil type pH

Ar~ IMananna ___________ Ak-I __ __ Lintonia silt loam __ _ _ _ ___ _ 60

Gooflria Auburn _____ bullbullbull _ _ Ga-L _ _ ___ Cecil sandy loam __ bull __ bull ___ _ 60 Experiment ____ bull ___ _ Ga-2 ________ bull __ do ____________ _ bullbull _bullbullbull _____ 62 Hawkinsville _____ bull __ Ga-a ____ bull ___ bullbullbulldo_ ___________ bull ____ _____ a6

Louisiana Baton Rouge __ bullbullbull __ bull La-I bullbullbullbullbull Olivier lilt loam bull __ ___ bull __ _ 56Saint Joseph_ La-2_ ____ Sharkey silty clay loam bullbull _ ____ _ 70

MissilllippiHolly Serings _____ bullbull __ 1 Ms-4 ___ Grenada Kilt loam ____ bullbull ________ 57 Poplarvtlle_______ bull 1 Ms-L bullbullbull __ Ruston sandy loam __ bull __ _ 58 State College _ ___ bullJ MK-2 bullbullbull Catalpll 2 sandy loam _bullbull _ _ ___ 1 68 Stonevill~_ -I Ms-~ __ - Sarpy S very fine sand _________ bullbullbull 65 West Pomt_ ____ MII-D bullbullbullbullbullIHouston c1ay bull ___ bullbull _bullbull _ 80

I North Carolina I I

Goldsboro _ bull NC-3bull _ Norfolk Kandy loam_ bull _ _ bullbullbull Nashville __ bull bull NC-L do _ _ 68 Raleigh _ _ j NC-4__ Cecil fine sandy loam 68 Rocky Mount bull __INC-2 bull Norfolk sandy loam__ 64 State3ville __ _ _ NC--5__ Cecil fine sandy loam __

Oklahoma I Perkins bullbull _ j Ok-I _ _ I Canadian Iandy loam

I 61

South Carolina II Chester _ bull SC-4 bullbull _I Appling Illndy loam 52 Clemson _- SC-L _bullbull 1 Cecil sandy loam _ _ 54 Florence bull I~q-- - Dunbar sandy loam bull __ bull 54 Jefferson S0-8 Lakeland fine sand ___ 56 KathwoOlL SC-l bull I Cahaba fine Iandy loam _I 58 Pontiac bull bull ~C~_ _I Norfolk sandy loam ___ - - 1 50 Smoaks - - SC 6 _ _ Blanton fine Iand ______ bull i 56 Woodruff _ bull SCmiddot7 _bull Cecil sandy loam _ bull I 54

Texas iCollege Station _ ~t rx-1~~ ~ j Lufkin fine sandy loam 50Temple__ -J Tx-2bull Houlton black clay ifI

Tennesse Jackson Tn-2 i Lintonia silt loam _ _ _ 55Knoxville _ Tn-I Decatur Ii1ty clay loam 55

Virginia Holland_____ Va I Onllow sandy loam _ j6

1 Planting locations will be refcrJed to by this code in text to conserve spac( When more thaIj one planting in a season has been made at the same location the successive plantings Ilrc referred to as a b c and d

bull

bull

Name ulled at time the experiments were conducted With recent revisiolls

in soil classification this soil is probably Verona 1I Name u3ed at time the experiments were conducted With recent revhlions

in soil classification this soil is probably Bosket bull

9

bull

bull

bull

COTTONSEED TREATMENT

TA8LE 2-Characteristics of the lots of seed used in the A test 1936-99

Seedling emergence 8i per- r---shyr-I centage of seeds planted Internal

~ _____ ~_ __~_ _0 ~I infection State Code U d d Acid- I Fungi infesting of acidshy of

ntreate see s delinted untreated seeds I delinted origin an steamed sand Reeds in I seeds I - testshy

i Total IHealthy tubes I I~-6--1A-99-2~--_I--- 47 90 -C-g--F-m-__-_-_-_-__-_--_j-F-m--C-g-(-6)-a- -s-c-

36-81--- 69 40 85 Cg Iltm_~_ ______ Fm Cg (5) __ S C 36-B2 t 87 8 90 Fm____ bullbull _______________ S C 136-C---1 i5 45 89 Cg Fm ________ bullbull Cg (9) ______ S C 36-0___ 70 I) 86 Cg Fm ______ bull ___ Fm Cg (33)_ S c 36-E ____1 53 34 60 Cg Fm _________ Cg (6) ___ bull __ S C 36-F_-- 54 20 57 Cg Fm__________ Fm Cg (15)_ S C 36-G __ bullbull 50 31 84 Cg Fm__________ Cg (7) ______ S C

19$7 37-A __ _1 91 35 91 Cg Fm ___________________ bull ___ Ala 37-B1_ 80 43 88 Cg Fm__________ Cg (4) ______ Ga 37-B2 t-l 95 95 96 Fm ___________________________ S C 37-C __ _ 72 29 85 Cg Fm ____________ bull __________ Miss

f37-0__ _ 62 52 81 ICgFm _______bull _ Cg (1)------ Missa7-E- __1 69 42 78 Cg Fm__________ Cg (3) ______ S C 3i-F____ 40 40 24 Fm Xm ______________________ Okla 37-G __ 67 67 82 Fm______________ _ ________ Okla 37-H _i 79 59 80 l Cg Fm__________ Cg (2) __ __ N C

18 I I38-A __j 54 50 90 I Fm Rn ___ bull _______ bull _____ bullbull _ __ Calif 38-B 6__ 35 33 72 I Fm Rn Xm _____ ------------ Okla38-C __ l 80 22 84 Cg Fm ______ bull ___ Cg (3) ______ S C 38-0L __ 72 14 80 Cg Fm __________ Cg (4) ______ S C 38-02 1bullbull j 77 75 88 Fm ______ bull____________________ S C 38-EL 66 17 82 Cg Fm ___ bull ______ Cg (4) ______ S C 38-E2 __ 1 80 70 81 Cg Fm________ -- _ _________ S C 38-F___ l is 56 90 Cg Fm _________ Cg (2)_ ___ NC

1939 I ~t~==~ ~ ~~ ~F~pmiddotRn~-xniI-Xril~ gk~39-Cl__ 66 58 90 Cg Fm __ bull____ __ Cg______ bull ___ N C a9-C_ 1_ 90 90 90 I F N C 39-0bull 71 18 91 1 C~-F-R__~~nfi(10)--= SC 39-E ___ i 54 37 90 ICg Fm Rn ______ 1 Cg (9) ______ Miss 39-F __ 1 52 28 i3 Cg Fm ____ bull _____ ____________ Ga

39~~__ ~~ _ 37 ____~~_J~m~n Fsp_- __ ) bullbull __ _ _ _ _ _ _ Tex

t The several species of fungi are indicated as follows Cg = Colletotrichum gossypii Fm = Fllsarium11l1l1liliorme Fsp = FU8arium spp Rn=Rhizopus tligriCIJIIS Xm = XallthomOllaH maivacearllllt

~ Individual lots of seed are designated by the letter or letter and numeral following the number used to designate the year in which it was planted

1 Number of fleedlingll obtained from 100 acid-delinted seeds that were infected by C gossYllii are indicated by numbers in parentheses

bull Lots with 2 after the designating letter are the somiddotcalled 2-year-old seed or seed from next to the last crop preceding the year in which used a11d are of the lIame variety as the preceding lot of 1-year-old seed designated by the same letter and I which was usually grown in the same locality

54-year-old seed II ayear-old seed

10 TECH~ICAT BULJI~TINI025 U s D1wr OF AGHlCUrrUlm

treatment the sublots were divided into the requisite amounts for shipment to the cooperators Generally all treatments were made bull during the last 2 weeks in March while the individual field plantshyings were macle from the first week in April to the first week in May

The acid-delinted seed used in the experiments in 1936 1937 1940 and 1942 were delinted with concentrated sulfuric acid then washed over a sieve with a stream of water and finally immersed for 3 minutes in water containing an excess of CaCO The seed were again washed to remove the adhering carbonate and then dried on a wire sueen at about 25 C for not less than 24 hours before bagging rrhe acid-delinted seed used in the B tests of 1938 and 1939 were prepared by essentially the same method except for the omission of CaCO The delinted seed used in 1941 were prepaled at a commercial acid-delinting plantl) The seed after delinting were sepalatecl into two fractions the floaters and sinkshyers on the bashl of their specific gravity in comparison to that of waiel Pheil characteristics are given in the description of the seed lots lIsed ill th( B test of 1941 (see table 9) For comparison with this method of dclinting Hced delinted in the laboratory was included in foicvelal plantings

The reg-inned 01 machine-delinted sublots wcre preparcd at various gins 01 oil mills and varying quantities of lint were removed The details are given in connection with the description of seed lIsed each ~eal in the B test bull

PIOT TECIINIQUE

Replicated plotH fully randomized to permit analysis of the data by the anal~sis of variance method were used in all plantshyings The method of planting Iate of seeding and final spacing of the plants were left to the judgment of the individual cooperashywIs Generally the handling of plots approximated the general farm pJactice of the region in which thc plantings were made The several methods of planting ued ranged from hand dropping a definite number of seedH at a predetermined spacing to the use of animal-drawn onc-row plantels When planters were used the rate of seeding was calculated from the weight of the seed planted Regardless of efforts to calibnlte the planters to distribshyute about 10 Heed per foot in most plantings there were differshyclces as great aH 25 percent in the rate of seeding of the several lots of seed used in the same planting These differences were directly associated with the amount of lint on the seed However the differences in the lite of se(ling between the untreated and treated seed of the same lot generally did not exceed 3 percent a diffelence small enough to permit relatively accurate comparishysons of the effect of treatment in field plantings

r Cottonseed Dclinting COlp inc B1ufT Alk bull

11

bull

bull

COTTONSEED TREATMENT

The statistical analysis for most of the plantings in which mechanical planters were used are based on 4 replications of apshyproximately 500 seeds ill 50-foot rows However 100-foot rows planted at a rate of about 10 seeds per foot were used in certain plantings of the B test In the Oklahoma and Tennessee plantings in which the seed were dropped by hand a smaller number of seeds usually about 100 were planted in each replication Since in these plantings a definite number of seeds were planted the accuracy that was possible in the percentage of emergence calcushylations largely compensated fOI the smaller number of seeds planted as compared to the plantings in which mechanical planters were used All data on seedling emergence and survival are reshyported on the basis of 100 seedsu although as indicated the number of iced planted varied from 100 to 1000

C()LIEltTIO~ ~I) I~TEHIHEIATIO~ or DAIA

Because of the impotmiddottance of h~1ing companlble data from all locations on seedling emergence and survival at the time of thinshyning the following criteria were adopted for the classification of seedlings in making counts

1 EliltIYcc lind tellllhll-To include all seedlings that have raised their cotyledons abov( (free flom) the soil and have alleast one nOlllally expanded cotyledoll flce of the seed (oat SlIch geedlingR should be 1I0lmal ill appenlllllCC and not so badly disca~ed as to pn~clude survival

2 Emeryed nllli disllIscd-Seedlings of which lhe cotyledon hnve emelged from the soil reganless of whethel they are enclosed ill 01 free of the seed coat but at the time of the count arc either dead 01 so hadly (iHeasc( as to preclude survival as llIay be indicated by willing or abscnce of normal cotyledons

3 Partially c1IwJyed-Seedlings with any part showink above lhe soil bllt inslIfficiently developed to ascertain the probability of normal healthy emershygence

In actual practice it was found very difficult to obtain counts of claHses 2 and 3 that would be of value fOl statistical analysis Consequently all analyses reported in this bulletin with a few exceptions to be noted later are based on the counts of the healthy emerged seedlings

]n all plantings an eftort was made to make a seedling count at the time of thinning or at a corresponding stage of seedling deshyvelopment in those plantings that were not thinned At thi- time about tl weeks after planting most plants had ftom three to fiv~ true leaves and there was little likelihood of fLllmiddotther losses from seedling diseases This count referred to as the final seedling count was used to calculate the percentage of surviving seedlings

HAil nlllllbtmiddotrs given in the tables to show seedling emelgcnce and sLlrviv~d COllsClluently arc pelcentages 10 avoid confusion betw(len the sev(lJal senses in which pcrc()nt mijht be lIsed all diflelenccs delived from the subtraction of two percentage arc called numerical differences increases 01 decreases while percentage is used to refer to the relalive Hiz( of two cnuIg-enccs eg- when the emcrgcnce of the untreated seed was 40 percent and that of the treated seed 60 percnt the nUllIerical difference in elllergence was 20 percent but the percentage increase in elllergence for treatment was 50 percent