12. Robinson Advances in PGRs' for Chemical ThinningBloom Thinning Options (Hormone Thinners) • BA+GA4+7 (Promalin, Perlan, Typy) •Causes more typeyfruit for Delicious, Gala and

AdvancesinPGR’sforChemicalThinning

TerenceRobinsonand PolianaFrancescatto

HorticultureSection,CornellAgriTechGeneva,NY,USA

Chemical Thinning Options• Bloom

• AmmoniumThiosulfate(ATS)• LimeSulfurandOil• Promalin• Maxcel• NAA• Amide-Thin

• PetalFall(fruitsat5-6mm)• Sevin• AmideThin• Maxcel+Sevin• NAA+Sevin• Maxcel+NAA• Metamitron

• Fruitsat11-13mm• NAA+Sevin• Maxcel+Sevin• Maxcel+NAA• Metamitron

• Fruitsat15-20mm• NAA+Sevin• Maxcel+Sevin+Oil• Ethrel+Oil• ACC+Maxcel• Metamitron

Bloom Thinning Options (Caustic Thinners)• AmmoniumThiosulfate(ATS)

• Burnsstigmaofpistil• Causesmildleafphytotoxicitybutnoeffectonfruitfinish• Requires2-3applications• WhenusedwiththePTGMcanachieveasubstantialportionofthinningjob• Hasaneutraleffectonfruitsize• NotregisteredasathinnerinNYbutcanbelegallyusedasabloomtimefoliarfertilizer

• ImprovesreturnbloomofHoneycrisp

• LimeSulfurandOil• Burnsstigmaofpistilandalsothestyle• Killspollentubegrowthinthestyle• More“reachback”tokillpollentubesthataregrowingthanATS• Causesmildleafphytotoxicitybutcanalsocausesomefruitfinishproblemsinsomeweatherconditions

• Requires2-3applications• Fishoilorsoybeanoilorsummersprayoils(highlyrefined)workalmostequallywellwithaslightedgetofishoil

• WhenusedwiththePTGMcanachievethemajorityofthinningjob• Hasaneutralornegativeeffectonfruitsize• NotregisteredinNYbutcanbeappliedasafungicide.HowevertheMillerChemicalbrandofLimeSulfurprohibitsuseduringbloom

Table 1. Effect of Alternatives of Fish Oil on Thinning Efficacy of Lime Sulfur. (Empire at Geneva NY 2003 Data)

Trt No. Treatment Description

Fruit No./ Tree

Fruit Size (g)

Cropload Adj. Fruit Size (g)

1 Unthinned Control 288 146 149 2 2.0 gal ATS/100 gal @ 80% FB 156 154 150 3 2.5 gal Lime Sulfur+2.0 gal Fish Oil/100 gal @ 80% FB 181 150 146 LSD P≤0.05 94 11 10 Contrasts FOLS @ FB vs ATS @ FB NS NS NS Fish Oil vs Ultra Fine Oil NS ** * Fish Oil vs Vegetable Oil NS ** * Fish Oil vs Regulaid NS NS NS Fish Oil vs Silwet NS ** * Table 2. Effect of Organic Thinners on Gala Fruit Size at Geneva NY. (2003 Data)

Trt No Treatment Description

Fruit No./ Tree

Fruit Size (g)

Cropload Adj. Fruit

Size (g) 1 Unthinned Control 608 139 153 2 2.0 gal ATS/100 gal @ 80% FB 472 143 142 3 2.5 gal Lime Sulfur + 2.0 gal Fish Oil/100 gal @ 80% FB 457 153 156

11 7.5ppm NAA + 1pt Sevin XLR @ 10mm Fruit Size 442 152 154 12 100 ppm BA + 1pt Sevin XLR @ 10mm Fruit Size 426 162 161

LSD P≤0.05 118 14 12 Contrasts ATS vs FOLS NS NS * FOLS vs Unthinned Control * * NS ATS vs Unthinned Control * NS * ATS vs BA/Sevin * * * FOLS vs BA/Sevin NS * *

FOLS vs BA/Sevin NS * *

Bloom Thinning Options (Caustic Thinners)• WillblossomthinningeverbeacceptedintheEast?

• TheadditionofthePTGMisasignificantadvance• Measurementofstylelengthiscritical• Ifsepalsareremovedthevisiblelengthofthepistilislongerthanshowninthispicture

• Ifstylemeasurementistoolongthenchemicalapplicationisdelayedandtoolittlethinningachieved

• LimeSulfurandOilismoreeffectiveforthinningthanATSbuthasgreaternegativeeffectsonplantmetabolismandthusdepressesfruitgrowthrateforseveraldaystoaweek

• Forlargefruitedvarieties,thetemporarysuppressionoffruitgrowthfromcausticthinnerscauseslittleconsequencebutwithsmallfruitedvarietiesthedepressionoffruitgrowthisaproblem

PhotofromGregPeckpresentation

Bloom Thinning Options (Hormone Thinners)• BA+GA4+7(Promalin,Perlan,Typy)

• Causesmoretypey fruitforDelicious,Galaandothervarieties• Insomeyearscancausesomethinning• Whentemperaturesarewarmithasagoodeffect.• Timingisatearlykingbloomandwellbeforefullbloom• Userateof2pt/acregivesalowamountofBAcomparedtoMaxcel userates

• BA(Maxcel,Exilis,Riteway)• Causesmoreblockyfruit(notelongated)• Isaverymildthinneratbloombutcanincreasefruitsize• Increasescelldivisiontocreateapotentiallylargerfruit• Workswellinwarmconditionsduringbloombutpoorlyincoolconditions(1yearoutof2-3thereisagreatresponse).

• Userateof8pt/acregivesahighamountofBAcomparedtoPromalin userates

• NAA(Fruitone,Pomaxa,Refine)• Amildthinner(safe)whenusedatbloom• Canbesprayedsafelyathighrateof10ppm• Hasaneutraleffectonfruitsize• Littleornodepressionofphotosynthesisatbloom• CanhelpimprovereturnbloomonHoneycrisp

• NAD(Amide-ThinW)• Amildthinner(safe)whenusedatbloom• Canbesprayedsafelyathighrateof8oz/100• Hasaneutraleffectonfruitsize• Littleornodepressionofphotosynthesisatbloom• CanhelpimprovereturnbloomonHoneycrisp

0

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Perc

ent f

ruit

set (

%)

Measurement time

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ent F

ruit

Set

Measurement time

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UntreatedControl Promalinthen3Maxcel/Sevin

Maxcelthen3Maxcel/Sevin

ResultsofPrecisionThinningofGalaatGenevain2013

Treatment Initial After After After After TargetFruit Bloom PF 10mm 18mm FruitNumber Spray Spray Spray SprayNumber

UntreatedControl 4430 1536 1217 1299 1288 335Promalin,3Maxcel/S4430 1524 992 933 673 335Maxcel,3Maxcel/S 4430 1051 992 981 567 335

100

120

140

160

180

200

Frui

t Siz

e (g

)

0 5 10 15 20

Crop load (fruit no/cm2 TCA)

Bloom Thinning Issues• WhyisblossomthinningmoresuccessfulintheWest?

• Moreconsistentweatheratbloom• Lessrusseting• Betterrelationshipofcroploadandfruitsize,thusifLSandOildepressfruitgrowthforafewdaystheystillcanachieve80-88countGala

Washington

NY40

60

80

100

120

140

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180

200

0 5 10 15 20 25 30 35

Fru

it S

ize

(g)

Crop load (fruit no/cm2 TCA)

2007

2004

2010

2006

2008

2005

2009

Bloom Thinning Options• ConclusionsandRecommendations

• UsethePTGMandsprayATSorLimeSulfurandoil(iflegal)2or3timesduringbloomforlargefruitedvarieties:• Honeycrisp• Fuji• Evercrisp• McIntosh• Delicious• Cortland• Rome• Jonagold• NY2• Otherlargefruitedvarieties

• Useahormonetypethinnerforsmallfruitedvarietiesduringbloom• Gala• NY1• Jazz• Empire• Macoun• PinkLady

•Donotspraycausticthinnersunderslowdryingandwetconditionsorifthereisfrost•Frostcausesdamagetofruitskinandcausticthinnersthencauserussetting

2

3

4

5

6

0 5 10 15 20 25Days After Petal Fall

Cro

plo

ad (

fruit

/cm

2T

CA

)

0

5

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25

Fru

it D

iam

eter

(m

m)

Series4BA/SevinNAA/SevinUnthinned ControlFruit Diameter

AtPetalFalltheeffectofNAA/Sevin orBA/Sevin ismild.Afewdaysafterpetalfalltheeffectisgreaterbutstillverysafe

FruitsetofDelicious,GalaandMcIntoshwaslowestwhenchemicalthinnerswereappliedat200-250degreedaysafterfullbloom

BottomLine:Applythinnersformaximumeffectat200-250DDafterbloom

Results–ChemicalThinning

-6

-4

-2

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2

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0 5 10 15 20

Slop

e of

Car

bohy

drat

e Ef

fect

on

Fina

l Fru

it nu

mbe

r (fru

its/g

carb

ohyd

rate

)

Days after Petal Fall

DeliciousGalaMcIntosh

Results– ChemicalThinning

AtpetalfallthereisaverysmalleffectofcarbohydratebalanceonthinningresultsAtlatertimestheeffectvariedfrom1fruitto4fruitspergofcarbon

Results– byyearYeartoYearVariabilityinresultsatpetalfalland18mm

Bestthinningwasalwaysbetween200-250DD

Takehomemessage:TimethinningspraysbyDDandtarget200-250DD

Petal Fall Thinning Options• Carbaryl(Sevin)

• AmildthinneratPetalFall(verysafe)• Limitedsolubilityinwater(Ratesabove1pt/100arenotsolublebutinsuspension)• Ifappliedat2pt/100ratethenitcanbere-wettedandgiveadditionalthinning• Hassomeinsectcontrolbenefitsifappliedat2pt/100rate

• BA+Carbaryl(Maxcel,Exilis,Riteway)• BAaloneisaverymildthinner(safe)butcanincreasefruitsize• Increasescelldivisiontocreateapotentiallylargerfruit(Useonsmallfruitedvarieties)• WhencombinedwithCarbaryltheefficacyismuchbetter.• ThecombinationofBA/Sevin workswellinwarmconditionsduringbloombutpoorlyincoolconditions(1yearoutof3thereisagreatresponse).

• UsehighrateofBA(4-8pt/acre)• Useonly1ptCarbarylper100sothatthereislittlechanceofre-wettingandexcessivethinning.

• NAA+Carbaryl (Fruitone,Pomaxa,Refine)• Avoidratesabove3oz/100sinceitdepressesphotosynthesisathighrates.• Hasaneutraleffectonfruitsize• WhencombinedwithCarbaryltheefficacyismuchbetter.• CanhelpimprovereturnbloomonHoneycrisp• AvoidwithFujiandDelicious(causespygmyfruitifBAusedlater)• Avoidsurfactants(Regulaid)sincetheydramaticallyincreasetheuptakeofNAA

• NAD(Amide-ThinW)• Amildthinner(safe)whenusedatpetalfall• Canbesprayedsafelyathighrateof8oz/100• Hasaneutraleffectonfruitsize• Littleornodepressionofphotosynthesisatpetalfall• CanhelpimprovereturnbloomonHoneycrisp

New Petal Fall Thinning Options without Carbaryl

• BA+NAA• ThecombinationofBAwithNAA(3oz/100)thinssimilarlytoBA+Sevin.• VaryrateofBA(4-8pt/acre)dependingonthevariety

• BA+NAD• ThecombinationofBAwithNAA(8oz/100)thinssimilarlytoBA+Sevin.• VaryrateofBA(4-8pt/acre)dependingonthevariety

• Metamitron (notyetregistered)• Aphotosynthesisinhibitor• IfthereisacarbondeficititwillthinbutgenerallymildatPF• Canbesprayedsafelyathighrateof200-400ppm• Hasaneutraleffectonfruitsize• A40%depressionofphotosynthesis

• ItisnotaPGR-aphotosynthesisinhibitor(Usedasasugarbeetherbicide)

• Canbeappliedatnormalthinningwindow(petalfallto18mm)

• Worksbestwhenthereisacarbohydratedeficit• Cancausephytotoxicityatveryhighrates(leafdamage)

• RegisteredinEU,toberegisteredintheUSinthe

nearfuture.

Metamitron asanapplethinner

Metamitron

d

ab ab a ab aab

bcc

0

0.5

1

1.5

2

2.5

Contr

ol

Orch

ard co

ntrol

Metam

itron

4mm

Metam

itron

8 mm

Metam

itron

12mm

Metam

itron

16mm

Metam

itron

20mm

Metam

itron

24mm

Metam

itron

28mm

Thin

ning

effe

ct (f

ruits

per

clu

ster

)

Thinning effect

Metamitron had a wide window for thinning

Metamitron

a aba a a

bab

a a

100

110

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Contr

olOr

chard

contr

olM

etami

tron 4

mmM

etami

tron 8

mm

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mitro

n 12m

mM

etami

tron 1

6mm

Meta

mitro

n 20m

mM

etami

tron 2

4mm

Meta

mitro

n 28m

m

Frui

t wei

ght (

g)

Fruit weight adjusted by crop load

No differences were found in crop load adjusted fruit weight

PetalFall 12mmfruitsize

MildthinningatPetalFall. Thethinningeffectwasgreatestwhenmetamitron wasappliedat12mmfruitsize.

InNYourtrialsshowMetamitron isamildthinneratPetalFallandamuchbetterthinnerat10-18mm

FruitsetofDelicious,GalaandMcIntoshwaslowestwhenchemicalthinnerswereappliedat200-250degreedaysafterfullbloom

BottomLine:Applythinnersformaximumeffectat200-250DDafterbloom

Results–ChemicalThinning

Relationship between carbohydrate balance for 5 days after application of thinners and fruit set of Empire/M.9

apple trees.

0

0.1

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-150 -125 -100 -75 -50 -25 0

Carbohydrate Balance (5 day average)

Fru

it S

et (

pro

po

rtio

n o

f sp

urs

wit

h f

ruit

)

Untreated Control

BA

NAA

Decision Rules We Use to Make Recommendations

4-Day Av. Carb. Balance Thinning Recommendation+20g/day to +40g/day Increase Chemical Thinning Rate by 30%+20g/day to 0g/day Increase Chemical Thinning Rate by 15%0g/day to -20g/day Apply Standard Chemical Thinning Rate-20g/day to -40g/day Decrease Chemical Thinning Rate by 10%-40g/day to -60 g/day Decrease Chemical Thinning Rate by 20%-60g/day to -80 g/day Decrease Chemical Thinning Rate by 30%< than -80g/day Do not thin (many fruits will fall off naturally)

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Slop

e of

Car

bohy

drat

e Ef

fect

on

Fina

l Fru

it nu

mbe

r (fru

its/g

carb

ohyd

rate

)

Days after Petal Fall

DeliciousGalaMcIntosh

Results– ChemicalThinning

AtpetalfallthereisaverysmalleffectofcarbohydratebalanceonthinningresultsAtlatertimestheeffectvariedfrom1fruitto4fruitspergofcarbon

Effectsofmetamitron onyieldandsizeofGalaapples

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UntreatedControl

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Frui

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t num

ber

per

tree

Fruit No. per tree Fruit Size (g)

Results

Themaximumreductioninphotosynthesisduetometamitron was

around40%inbothyears

In2017withcoolertemperatures,therewasnotrateresponseandphotosynthesisreacheditslowestlevelaround7-8days

afterapplication.

In2016,withwarmtemperatures,therewasasignificantresponsetorateofmetamitron andthemaximum

reductioninwhole-treephotosynthesisoccurredthreedaysafterapplication.

ns

ns ns

a

ab

b

b

a

ab

bb

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NCER(%

ofthepre-treatmentvalue)

Daysaftermetamitronapplication

2016

0mgL-1200mgL-1350mgL-1500mgL-1

ns

nsns ns

a

bbb

a

bbb

a

bbb

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NCER(%ofthepre-treatmentvalue)

Daysaftermetamitronapplication

2017

0mgL-1200mgL-1350mgL-1500mgL-1

2016

2017

ResultsWhole-treenetCexchangerate

Chemical Thinning past the optimum time• Fruitsat15-20mm

• NAA+Sevin +Oil(1pt/100)• Marginallyeffectivewithoutoil

• Maxcel+Sevin+Oil(1pt/100)• Withouttheoil,BA/Sevin ismarginallyeffective• WithoilwehavehadverygoodsuccesswithGala

• Ethrel+Oil• Ethrel generatesethyleneintheplant• Powerfulthinningcombinationiftemperaturesarehot

• ACC+Maxcel• ACCisaprecursorofethyleneandprobablyworksbygeneratingethyleneinthefruit

• WehavehadgoodsuccesswithACConlyifcombinedwithMaxcel• WeareevaluatingACCwithregulaid oroil

• Metamitron• Veryeffectiveat15-18mmfruitsizeifthereisacarbondeficit• Canbesprayedsafelyatrateof200-400ppmdependingoncarbonbalance

• Hasaneutraleffectonfruitsize• Causesa40%depressionofphotosynthesis

0 100 200 300 400 500 600 700

Unt

reat

ed

18m

mM

/S

No

18m

m

18m

mEt

hrel

/oil

18m

mM

/AC

C

18m

mM

/oil F

ruit

Num

ber/

tree

Effect of 18mm Treatments

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/S

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/oil

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/AC

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18m

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/oil

Yie

ld/a

cre

(bu)


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/S

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/AC

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/oil

Frui

t Siz

e (g

)


0 2000 4000 6000 8000

10000 12000

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reat

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mM

/S

No

18m

m

18m

mEt

hrel

/oil

18m

mM

/AC

C

18m

mM

/oil C

rop

Val

ue ($

/acr

e)


Metamitron

d

bc

a aab

aab

abcc

0

5

10

15

20

25

30

Contr

ol

Orch

ard co

ntrol

Metam

itron

4mm

Metam

itron

8 mm

Metam

itron

12 m

m

Metam

itron

16 m

m

Metam

itron

20 m

m

Metam

itron

24 m

m

Metam

itron

28 m

m

Initi

al c

rop

load

(fru

its p

er c

m2

TCSA

)

Initial crop load

Can thin up to 28mm fruit size

A Lesson on Tree Row Volume and Thinning• Wesuggestcalculatingofamountofthinningchemicalsperacre

basedforthesizeofthetreecanopyusingTRV• AllofourratesintheCornellRecommendsareratesper100

gallonsofdilutespray• MostmodernorchardhaveaTRVof100-220gallonsofsprayto

fullywetthetree• Example:TallSpindletreesplanted3X11and12feettalland6feet

wide(43560/11=3960linearfeetofrowperacre*6*12*0.7/1000=200gallonsdiluteTRV

• Example:SuperSpindletreesplanted2X11and10feettalland4feetwide(43560/11=3960linearfeetofrowperacre*4*10*0.7/1000=111gallonsdiluteTRV

• Tocalculatetherateperacremultiplytherateper100bythefractionofTRV/100baserate• Example:TallSpindletreeswithTRV=200(concentrationfactoror

2.0)andaMaxcel rateof64oz/100gal=128ozMaxcel peracre• Example:SuperSpindletreeswithaTRV=111(concentrationfactor

of1.11andaMaxcel rateof64oz/100gal=71ozMaxcel peracre• Theamountofchemicalputinthetankistheperacreamount

regardlessofthevolumeofwater

A Lesson on Tree Row Volume and Thinning (cont.)

• Thevolumeofwaterperacrecanbevariedfromfulldilute(1X)to1/3thefulldilutevolume(3X)withoutdifferencesinthinningresponse• Example:TallSpindletreeswithTRV=200canbesprayedat

200gallonsperacre(fulldilute)orwithhalfthewatervolume(100gallons/acre)orat1/3watervolume(67gallonsperacre)

• Example:SuperSpindletreeswithaTRV=111canbesprayedat111gallonsperacre(fulldilute)orwithhalfthewatervolume(56gallons/acre)orat1/3watervolume(37gallonsperacre)

• Mixingprotocol• Example:TallSpindletreeswithTRV=200butsprayedat100

gallonsperacrewithhalfthewatervolume(64ozMaxcel/100galdilute*2=128ozMaxcel/acre*5acressprayedpertank=540oz/tank=5gallonsMaxcel/tank

• Example:SuperSpindletreeswithTRV=111butsprayedat50gallonsperacrewithhalfthewatervolume(64ozMaxcel/100galdilute*1.11=71ozMaxcel/acre*5acressprayedpertank=355oz/tank=2.77gallonsMaxcel/tank

Best Spray Pattern for Thinning • Theproblem:Thebottomhalfofthetreeisusually

overthinnedandthetopsoftreesareunderthinned• Thisisduetomorelightandthusmorecarbohydrates

availableforfruitletsinthetopsoftreesthaninthebottomsoftrees.

• Traditionalrecommendation• Nozzlethesprayersothetophalfofthetreereceives2/3of

thesprayvolumeandthebottomhalfofthetreereceives1/3• Thisspraypatterncontinuestooverthinthebottomofthetree

andunderthin thetopofthetree• Wehavedone4separatetrialswithhigherpercentages

directedtothetopofthetreeandthebestresultsarewhen80-100%ofthesprayisdirectedtothetopofthetree• Wesuggestthatforthebloomandpetalfallspraysthe

traditionalspraypatterof2/3and1/3isbest• Forthe12mmsprayswesuggestthepatternbechangedto

80%inthetopand20%inthebottom• Forthe18mmspraywesuggestthepatternbechangedto

100%inthetop

Questions?

Documents

12. Robinson Advances in PGRs' for Chemical ThinningBloom Thinning Options (Hormone Thinners) • BA+GA4+7 (Promalin, Perlan, Typy) •Causes more typeyfruit for Delicious, Gala and