Suppression of Boll Weevil Infestations (Coleoptera: Curculionidae) Occurring on Fallow-Season Cotton in Southern Texas by Augmentative Releases ofCatolaccus grandis(Hymenoptera: Pteromalidae)

Suppression of Boll Weevil Infestations (Coleoptera: Curculionidae)Occurring on Fallow-Season Cotton in Southern Texas by

Augmentative Releases of Catolaccus grandis(Hymenoptera: Pteromalidae)

K. R. Summy, S. M. Greenberg, J. A. Morales-Ramos, and E. G. KingSubtropical Agricultural Research Laboratory, Agricultural Research Service, U. S. Department of Agriculture, Weslaco, Texas 78596

Received November 11, 1996; accepted March 31, 1997

Augmentative releases ofCatolaccus grandis (Burks)were conducted in the Lower Rio Grande Valley ofTexas in an attempt to suppress infestations of bollweevil, Anthonomus grandis Boheman, occurring instands of ‘‘fallow-season’’ cotton (i.e., fields in violationof the 1 September stalk destruction deadline man-dated by Texas law). In each of five release sitesmonitored during the study period (October, 1994–March 1995), augmentative releases of C. grandiswereaccompanied by an appreciable increase in the inci-dence of parasitized boll weevils (primarily third-stage larvae and pupae infesting abcised cottonsquares) within a relatively brief time period. Therelatively high incidence of hostmortality caused byC.grandis in each release site was largely indispensible(i.e., would not have occurred in the absence of theparasite) and served to destroy significant numbers ofimmature boll weevils that appear to have been predis-posed to successfully overwinter. The potential role ofparasite augmentation in the management of the over-wintering boll weevil population in southern Texas isdiscussed.KEY WORDS: Boll weevil; Anthonomus grandis;

Catolaccus grandis; biological control; pest manage-ment; cotton.

INTRODUCTION

Catolaccus grandis (Burks), an exotic parasite indig-enous to southernMexico and northernCentralAmerica(Cate et al., 1990), is currently considered the mostpromising candidate for augmentative biological con-trol of boll weevil,Anthonomus grandisBoheman (Kinget al., 1993). Although stocks of C. grandis obtainedfrom the Mexican tropics have apparently failed toestablish in the southern United States (Johnson et al.,1973; Cate et al., 1990), augmentative releases of theparasite at rates ranging from 600 to 2500 females/ha/

week have resulted in effective suppression of hostinfestations on cotton during the commercial produc-tion season (Summy et al., 1995a; Morales-Ramos et al.,1994, 1995a).Augmentative releases ofC. grandis havebeen successfully integrated into the production of‘‘short-season’’ cotton in southern Texas and have beenshown to be compatible with potentially disruptivepractices such as mechanical cultivation and preemp-tive application of broad-spectrum insecticides (King etal., 1993; Summy et al., 1994a, 1994b). Moreover, C.grandis is amenable to mass propagation using in vivorearing techniques (Cate, 1987; Morales-Ramos et al.,1992; Roberson and Harsh, 1993), and in vitro rearingtechnology is currently under development (Morales-Ramos et al., 1995b; Rojas et al., 1995, 1996).Because of its demonstrated efficacy during the com-

mercial cotton season per se, Summy et al. (1995b)suggested that augmentative releases of C. grandismight also provide effective suppression of boll weevilinfestations occurring in stands of undestroyed cottonduring the postharvest ‘‘fallow’’ season, which is man-dated by Texas law and currently extends from 1September through 20 February in the Lower RioGrande Valley region. The latter authors demonstrateda significant increase in the incidence of host mortalitycaused byC. grandis in release sites and suggested thata significant percentage of the immature host stagesdestroyed by parasitism would have otherwise pro-duced adults capable of overwintering successfully.In order to evaluate the feasibility of parasite augmen-

tation in fallow-season cotton, we conducted a series ofaugmentative parasite releases designed to evaluate(1) the performance of C. grandis under weather condi-tions normally prevalent in southern Texas during thefall, winter, and early spring periods and (2) the impactof mortality caused by C. grandis on the dynamics ofhost infestations occurring in stands of fallow-seasoncotton.

BIOLOGICAL CONTROL 9, 209–215 (1997)ARTICLE NO. BC970536

209 1049-9644/97

MATERIALS AND METHODS

Parasites were reared in vivo using procedures devel-oped by Cate (1987) and modified by Morales-Ramos etal. (1992) and Roberson and Harsh (1993). Parafilmsheets each containing ca. 130 third-stage boll weevillarvae (obtained from the R. T. Gast Insect RearingFacility, Starkville, MS) were exposed to ca. 350 matedfemale parasites for a period of ca. 3 h under constantinsectary conditions (27 6 1°C; 65 6 5% RH; 12:12 hL:D). Sheets exposed in this manner were then placedwithin ventilated emergence containers for the dura-tion of the parasite developmental period (12–14 days).Following emergence, adult parasites were placedwithin plexiglas cages and allowed to oviposit for aperiod of 2–5 days, after which they were aspirated intocardboard cannisters (ca. 250 parasites per container)for transport to release sites.Parasite releases were conducted in five sites: (1) a

0.8-ha plot of unshreddedmature cotton located onARSfacilities in Weslaco in Hidalgo County (an initialrelease of 1000 mated females on 14 October, followedby four subsequent releases of 2000 females during17–26 October; 9000 total), (2) a 1.6-ha field of unshred-ded mature plants located near Cavazos in CameronCounty (two releases of 2000 females during 7–9Novem-ber; 4000 total), (3) a 6.7-ha field of cowpeas locatednear LaVilla in Hidalgo County, in which a consider-able amount of volunteer cotton had germinated (asingle release of 250 females within a 65 3 65-m quad-rat on 8 December), (4) an 11.5-ha field of potatoeslocated near Hargill in Hidalgo County, in which volun-teer cotton had germinated in abundance (four releasesof 250 females within a 65 3 65-m quadrat during 8–26December; 1,000 total), and (5) an isolated clump ofthree cotton plants (several years of age) located nearLaguna Atascosa in Cameron County (five releases of25 females at weekly intervals between 22 Februaryand 28 March; 125 total). The experimental cotton plotnear Weslaco was waived (from stalk destruction re-quirements) by the Texas Department of Agriculture(TDA) until 31 October; the remaining fields were bonafide violations of stalk destruction regulations that hadbeen detected by state regulatory personnel (whogranted permission to conduct the present research) orwere located independently by researchers involved inthe parasite evaluation.Parasite releases in the first four sites were evalu-

ated using a random sampling scheme designed toestimate densities of live and dead (including parasit-ized) boll weevils developing within cotton squares andbolls distributed in the plant canopy and on the soilsurface (Summy et al., 1995a,b). Samples consisting ofall fruiting structures (squares and bolls, attached andabcised) occurring within each of 10–20 randomlyselected 1.0-m2 sampling points (locations determinedby random numbers table) were collected from each site

at weekly intervals. Within fields in which cottonplants occurred at relatively low densities in a patchydistribution (i.e., the cowpea field near LaVilla and thefield of potatoes near Hargill), the cotton plant or clumpof plants nearest the randomly selected sample pointswas selected, and plant densities within the releasequadrat (65 3 65 m) was determined by an actualcount. Samples collected in this manner were dissected(under a stereomicroscope) in the laboratory, and num-bers of live, dead, and parasitized boll weevils of eachlife stage occurring within each type of fruiting struc-ture were recorded.A mechanical exclusion technique was employed in

each of four release sites to estimate the averageincidence ofmortality occurring among cohorts of imma-ture boll weevils exposed to searching parasites inrelation to counterparts protected from the latter.Groups of 25 squares naturally infested by immaturehost stages were placed within pairs of screen cagesdesigned to either exclude searching parasites (‘‘closed’’cages) or to allow ingress and egress of the latter viasmall openings (‘‘open’’ cages). In the sites at Cavazos,LaVilla, and Hargill, infested squares for such cagestudies were collected from the canopy at the timeparasite releases were initiated. Due to the limitednumber of cotton plants available at the Laguna Atas-cosa site, all infested squares present in the canopy oron the soil surface beneath plants on each collectiondate were collected and placed within an ‘‘open’’ cage;an equivalent number of infested squares (collectedfrom the canopy in other sites) were placed into the‘‘closed’’ counterpart. In all sites, such cohorts weresituated in pairs beneath the plant canopies and left forthe duration of the developmental period, after whichthey were returned to the laboratory and dissected(under a stereomicroscope) to determine stage at deathand mortality causal factors, including parasitism. Atotal of nine replicates were employed in the site atCavazos, eight at LaVilla, nine at Hargill, and five atLaguna Atascosa. Mean generation (total) mortalityoccurring among such cohorts were compared usingStudent’s t test.The propensity of immature boll weevils developing

in the various release sites to successfully overwinter(as adults, following emergence) was evaluated in aseries of laboratory feeding experiments. Cohorts of50–100 adults reared from cotton squares collectedfrom the various infestations at the time parasitereleases were conducted were placed within screencages (30 3 30 3 30 cm) provided with a source ofwater and maintained on an outdoor table and were fedan exclusive diet of squares for 21 days. Following thetermination of feeding activities, mortality occurringwithin each such cohort wasmonitored by direct inspec-tion at weekly intervals until the death of the lastindividual.

210 SUMMY ET AL.

RESULTS AND DISCUSSION

The 1994 fallow season was characterized by rela-tively mild weather conditions typical of those normallyoccurring in the Lower Rio Grande Valley region duringthe fall, winter, and early spring periods (Table 1; seealso Orton et al., 1967). The sequence of parasitereleases conducted during this period spanned a periodof ca. 5 months, and involved a diversity of habitats,ranging from dense stands of cotton regrowth (Weslacoand Cavazos) to relatively sparse infestations of volun-teer cotton distributed within other crops (e.g., cowpeasin LaVilla and potatoes in Hargill). Collectively, thesestudies clarified several important aspects of parasiteperformance during the postharvest period and concur-rently provided a rationale for the use of parasiteaugmentation in management of the overwintering bollweevil population.

Incidence of Parasitism in Release Sites

A prerelease census conducted in the 0.8-ha Weslacosite on 14 October revealed a dense infestation ofimmature boll weevils infesting both types of cottonfruiting forms (primarily squares) and indicated arelatively low incidence of parasitism byC. grandis andthe native parasite Bracon mellitor (Say) (ca. 1.6%apparent parasitism of third-instar boll weevil larvaeby both species, respectively) (Table 2). As C. grandishas invariably failed to establish in southern Texas andother areas of the southern United States (Cate et al.,1990), the presence of this parasite species prior to thefirst release probably reflected dispersal from nearbyARS insectary facilities (located ca. 500 m to thesoutheast), but may have also resulted from dispersalof parasites from field release sites used during theprevious summer (the closest of which was located ca.4.0 km to the southeast).Augmentative releases of C. grandis in the Weslaco

site (an initial release of 1000 mated females on 14October, followed by four subsequent releases of 2000females during 17–26 October; ca. 9000 total) were

accompanied by an appreciable increase in the inci-dence of parasitism during a relatively brief timeperiod (Table 2). As in previous field evaluations (Mo-rales-Ramos et al., 1995a; Summy et al., 1995a,b),attacks by C. grandis were almost entirely restricted tothird-stage boll weevil larvae and pupae and wereconcentrated among host individuals infesting abcisedsquares (91–100% of total). Within this segment of thehost infestation, the incidence of parasitism increasedca. 33-fold within 3 weeks of the initial release (from1.6% on 14 October to 52.5% by 31 October).A similar increase in parasitism was documented in

the 1.6-ha release site located near Cavazos (Table 3). Aprerelease census conducted on 7 November revealed adense infestation of immature boll weevils (most ofwhich occurred in abcised cotton squares) and a lowincidence of parasitism by the native parasites B.mellitor and Catolaccus hunteri Crawford (ca. 11.4%).Following a series of augmentative parasite releases(two releases of 2000 females during 7–9 November;4000 total), the incidence of parasitism byC. grandis (ofthird-instar host larvae and pupae infesting abcisedsquares) increased from 0 to 78.2% within a period of 7days (Table 3).In contrast to the previous sites, the volunteer cotton

TABLE 1

Summary of Weather Conditions in the Lower Rio GrandeValley of Texas during the 1995 Cotton Fallow Seasona

SiteReleaseperiod

Temperature (°C)(x 6 SE)

Precipitation(cm)Maximum Minimum

Weslaco 10/14–10/31 30.7 6 1.1 20.1 6 1.2 4.6Cavazos 11/07–11/14 29.3 6 1.2 18.9 6 1.1 1.8Lavilla 12/07–12/14 25.2 6 2.3 14.1 6 2.3 0.5Hargill 12/07–12/27 22.6 6 1.1 13.0 6 1.1 3.2Laguna Atascosa 02/22–03/28 26.2 6 1.1 13.9 6 0.9 2.9

a Source: USDA-ARS weather station, Weslaco, TX.

TABLE 2

Parasitism of Immature Boll Weevils by Catolaccus gran-dis, Weslaco, TX, Following the Release of 9000 Parasitesduring 14–26 October, 1994

DateHosts/m2

(x 6 SE)

%Apparent parasitisma

C. grandis Other

Attached squares (canopy)

10/14 6.9 6 2.0 0.0 0.010/20 1.9 6 0.6 0.0 0.010/27 0.2 6 0.2 0.0 0.010/31 0.8 6 0.3 11.1 0.0

Abcised squares (soil surface)

10/14 2.5 6 0.5 1.6 1.6b10/20 4.4 6 0.7 22.0 0.010/27 3.6 6 1.3 27.0 0.010/31 5.2 6 1.2 52.5 1.2b

Attached bolls (canopy)

10/14 0.0 6 0.0 — —10/20 0.0 6 0.0 — —10/27 0.2 6 0.2 0.0 0.010/31 0.8 6 0.7 0.0 0.0

Acsised bolls (soil surface)

10/14 0.2 6 0.1 0.0 0.010/20 0.1 6 0.04 14.2 0.010/27 0.2 6 0.2 0.0 0.010/31 0.8 6 0.3 22.0 7.3b

a Aggregate of third-instar larvae and pupae.b Bracon mellitor (Say).

211AUGMENTATIVE RELEASES OF C. grandis

plants distributed within the 6.7-ha field of cowpeasnear Lavilla and the 11.5-ha field of potatoes nearHargill were devoid of bolls and occurred at relativelylow densities (by actual counts, 278 and 369 plantswithin the 0.4-ha release quadrats of the LaVilla andHargill fields, respectively). Prerelease censuses con-ducted on 7 December revealed low-density boll weevilinfestations in both sites and a low incidence of parasit-ism by B. mellitor in the Lavilla infestation (Tables 4and 5). Following a single release of 250 female C.grandis in the LaVilla field on 8 December, the inci-dence of parasitized boll weevils within the releasequadrat (third-stage larvae and pupae infesting ab-cised squares) increased from 0.0 to 64.2% within aperiod of 6 days (Table 4). A sequence of releasesconducted in the Hargill site (four releases of 250females during 8–26 December; 1000 total) was accom-panied by an increase of similar magnitude (from 0 to87.5% parasitism of third-stage weevil larvae andpupae infesting abcised squares) within ca. 3 weeks ofthe initial release (Table 5).

Impact of Parasitism on Host Infestations

Each of these four releases demonstrated the abilityof C. grandis to parasitize significant numbers ofimmature boll weevils under environmental conditionsprevalent during the extended fallow season. The prac-tical significance of mortality caused by C. grandis,however, is largely predicated on two factors: (1) theextent to which such mortality is ‘‘indispensible’’ or‘‘irreplaceable,’’ i.e., would not have occurred had theparasite been absent from the life system (Southwood

1978), and (2) whether the immature boll weevilsdestroyed by C. grandis would have otherwise pro-duced adults capable of successful overwintering.Results of parasite exclusion experiments conducted

in four release sites (Cavazos, LaVilla, Hargill, and

TABLE 3

Parasitism of Immature Boll Weevils by Catolaccus gran-dis, Cavazos, TX, Following the Release of 4000 Parasitesduring 7–14 November, 1994

DateHosts/m2

(x 6 SE)


C. grandis Other


11/07 0.9 6 0.6 0.0 0.011/14 5.1 6 2.3 11.8 0.0


11/07 4.4 6 0.8 0.0 11.4b11/14 11.9 6 2.5 78.2 0.0


11/07 0.0 6 0.0 — —11/14 0.1 6 0.1 0.0 0.0


11/07 0.1 6 0.1 0.0 0.011/14 0.0 6 0.0 — —

a Aggregate of third-instar larvae and pupae.b Bracon mellitor (Say) and Catolaccus hunteri Crawford.

TABLE 4

Parasitism of Immature Boll Weevils by Catolaccus gran-dis, LaVilla, TX, Following the Release of 250 Parasites on8 December, 1994

DateHosts/m2

(x 6 SE)


C. grandis Other


12/07 0.2 6 0.2 0.0 0.012/14 0.4 6 0.4 0.0 0.0


12/07 1.4 6 1.2 0.0 0.012/14 5.6 6 1.6 64.3 17.9b


12/07 0.0 6 0.0 — —12/14 0.0 6 0.0 — —


12/07 0.0 6 0.0 — —12/14 0.0 6 0.0 — —

a Aggregate of third-instar larvae and pupae.b Bracon mellitor (Say).

TABLE 5

Parasitism of Immature Boll Weevils by Catolaccus gran-dis, Hargill, TX, Following the Release of 1000 Parasitesduring 7–27 December, 1994

DateHosts/m2

(x 6 SE)


C. grandis Other


12/07 0.4 6 0.4 0.0 0.012/13 0.0 6 0.0 — —12/27 0.8 6 0.4 0.0 0.0


12/07 0.8 6 0.6 0.0 0.012/13 1.0 6 1.0 40.0 0.012/27 0.5 6 0.3 87.5 0.0


12/07 0.0 6 0.0 — —12/13 0.0 6 0.0 — —12/27 0.0 6 0.0 — —


12/07 0.0 6 0.0 — —12/13 0.0 6 0.0 — —12/27 0.0 6 0.0 — —

a Aggregate of third-instar larvae and pupae.

212 SUMMY ET AL.

Laguna Atascosa) clearly demonstrated that the rela-tively high incidence of host mortality caused by C.grandis was largely indispensible (Table 6). Cohorts ofimmature boll weevils exposed to parasite activity inthe Cavazos infestation exhibited an incidence of gen-eration (total) mortality that was nearly twice that ofcounterparts protected from searching parasites (90.0and 50.9% mortality, respectively) (t 5 9.481, df 5 8,P , 0.001). A similar contrast was evident among co-horts monitored in the infestations near LaVilla (50.1and 20.6% mortality among exposed and protectedcohorts, respectively) (t 5 3.22, df 5 7, P 5 0.015) andHargill (66.1 and 38.0% mortality, respectively)(t 5 2.554, df 5 8, P 5 0.034). Release of relatively fewparasites in the vicinity of an isolated clump of cottonplants located near LagunaAtascosa (five releases of 25mated females between 22 February and 28March; 125total) was accompanied by a pronounced increase ingeneration mortality among cohorts exposed to para-site activity relative to hosts protected from searchingparasites (96.7 and 11.1%, respectively) (t 5 7.383,df 5 4; P 5 0.002).In a previous study, Summy et al. (1995b) noted that

a segment of the adult boll weevils reared from cottonsquares during September and October were poten-tially capable of surviving the remainder of the cottonfallow period. When subjected to limited diet regimens(an exclusive diet of either squares or bolls for a periodof ca. 21 days), adults of both sexes exhibited the abilityto survive periods up to 5 months without subsequent

feeding. This capability was clearly evident amongcohorts of adult boll weevils reared from squares col-lected from several of the release sites during the fallowseason of 1994 (Table 7). Following the termination of alimited (21-day) feeding period, remaining lifespanaveraged 11.5 additional weeks for a series of cohortsinitiated on 7 November (a maximum of 20 weeks), 10.7additional weeks for cohorts initiated on 2 December (amaximum of 18 weeks), and 4.5 additional weeks forcohorts initiated on 17 January (a maximum of 9weeks). Percentages of these cohorts that surviveduntil the subsequent production season (arbitrarilydesignated as 20 February, the earliest legal plantingdate for cotton in the LRGV region) ranged from aminimum of 52.0% for the series of cohorts initiated on7 November to a maximum of 68.8% for those initiatedon 2 December.Thus, the relatively high incidence of parasitism

evident in each of the five release sites was significantin two important respects. As most of the mortalitycaused by C. grandis was indispensible, the parasiteclearly effected a suppression of host infestations occur-ring over a wide range of densities. More importantly,mortality caused byC. grandis served to destroy signifi-cant numbers of immature boll weevils that appear tohave been predisposed to successfully overwinter.

Potential Role of Parasite Augmentationin Management of the OverwinteringBoll Weevil Population

Crop residue management has long been recognizedas one of the most effective means by which to suppresspopulations of overwintering boll weevils and remainsa cornerstone of the boll weevil management effort insouthern Texas (Summy and King 1992). Destruction of

TABLE 6

Mortality of Immature Boll Weevils Occurring in thePresence and Absence of Parasites in the Lower Rio GrandeValley of Texas, 1994–1995

Cohort Size

% Generationmortalitya(x 6 SE)

% Parasitism

Realb Apparentc

Cavazos, 7–14 November

Exposed 100 90.0 6 2.7 a 38.0 75.9Protected 100 50.9 6 3.1 b 0.0 0.0

Hargill, 7–27 December


LaVilla, 7–14 December


Laguna Atascosa, 22 February–28 March


a Means followed by same letter not significantly different at 5%significance level (Student’s t test).

b Mortality as a percentage of total numbers in original cohort.c Mortality as a percentage of numbres surviving to third larval

stage.

TABLE 7

Remaining Lifespan of Adult Boll Weevils Following theTermination of Feeding Activities, 1994–1995

SexCohortsizea

RemainingLifespan (weeks)

x 6 SE Range

Cohort 1 (fed 7–28 November)

Male 53 11.1 6 0.9 2–20Female 47 11.8 6 0.8 4–20

Cohort 2 (fed 2–29 December)

Male 31 10.6 6 0.9 1–18Female 20 10.8 6 1.1 1–17

Cohort 3 (fed 17 January–6 February)

Male 44 4.3 6 0.4 1–9Female 25 3.6 6 0.5 1–9

a Number surviving a 21-day feeding period (dates given in paren-theses).


cotton plants following harvest deprives the overwinter-ing boll weevil population of its principal reproductivehost (Summy et al., 1988) and has been shown tosignificantly reduce the incidence of overwinter sur-vival of the pest by several means, e.g., as adults orimmature stages infesting cotton residue located eitherabove or below the soil surface (Summy et al., 1992a,b).Although considerable progress has been made in thesouth Texas stalk destruction effort during the pastdecade, a continuation of producer apathy (by a minor-ity of local producers) and inclement weather condi-tions (which may delay stalk destruction operations foran extended period of time) continues to impede theeffort at present, and may be expected to do so in thefuture.In situations in which stalk destruction by conven-

tional cultivation proves to be difficult, if not impos-sible, prior to the mandated 1 September deadline,augmentation of C. grandis provides a potentiallyeffective means by which to ameliorate at least oneimportant aspect of the stalk destruction problem. Asattacks by C. grandis are largely restricted to imma-ture stages of the host, augmentative releases of theparasite in stands of fallow-season cotton cannot beexpected to suppress the incidence of oviposition byoverwintering adult boll weevils to any appreciableextent. Nevertheless, the parasite is clearly capable ofdestroying significant numbers of progeny produced bysuch adults, an effect which would tend to substantiallyreduce the incidence of boll weevil recruitment occur-ring in delinquent fields during the interim betweendetection by state regulatory personnel and the time atwhich such fields are terminated by conventional culti-vation. Suppression of such recruitment appears to becritical, as a significant percentage of boll weevil pro-greny produced in southern Texas during the fall andwinter periods appear to be predisposed to overwinter-ing successfully. This effect of augmentative parasitereleases in fallow-season cotton would be analogous tothe ‘‘fall-diapause’’ concept, which has traditionallyinvolved an attempt to suppress recruitment and over-winter survival of adult boll weevils through applica-tion of broad-spectrum insecticides (e.g., Brazzel, 1959).Because of the limited ability of C. grandis to attackimmature boll weevils infesting cotton bolls (see Tables2–5), augmentative releases of C. grandis would prob-ably achieve their greatest impact in cotton fieldsterminated prior to boll formation.Use of parasite augmentation on a large scale will

ultimately require the availability of inexpensive mass-production technologies and efficient disseminationsystems. Current production costs for C. grandis usingin vivo rearing techniques are relatively high (King etal., 1995), but may be expected to decline substantiallywith the development of novel in vitro rearing technolo-gies (Rojas et al., 1995, 1996). Research on these topics

should be pursued vigorously, as they will facilitate theintegration of biological control strategies into a cul-tural control program that currently represents thefoundation of the boll weevil management effort insouthern Texas and other areas.

ACKNOWLEDGMENTS

We express our appreciation to J. M. Caballero and J. Cavazos fortechnical assistance during the study and to J. H. Everitt, J. W.Norman, Jr., M. J. Lukefahr, and J. V. French for reviews of themanuscript.

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Suppression of Boll Weevil Infestations (Coleoptera: Curculionidae) Occurring on Fallow-Season Cotton in Southern Texas by Augmentative Releases ofCatolaccus grandis(Hymenoptera: Pteromalidae)