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A single herbicide (Trimec® or Strike 3™) application in early season (March or April) was made to marginal areas around fields in 23-km2 test sites of the Mississippi Delta in 1999, 2000, and 2001. The herbicide was used to kill broadleaf weeds in the marginal areas that served as hosts for tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois). The herbicide treatment caused a significant reduction in wild host densities in the treated test sites in all 3 yr. Tarnished plant bug populations in treated test sites did not increase significantly in the treated marginal areas during April and May after treatment of the margins in the first 2 wk of March in 2000 and 2001. The herbicide application was made in the first 2 wk of April 1999, and plant bug populations increased in treated marginal areas in this year. The increase was thought to be caused by plant bugs moving to Italian ryegrass, Lolium multiflorum Lamarck, a previously unreported plant bug host, which was not affected by the herbicide. Laboratory tests showed that plant bugs would oviposit in flowering or nonflowering ryegrass when caged on ryegrass for a 6-d period. Newly emerged nymphs developed into adults (56%) when reared on floral spikelets of ryegrass, but no adults were obtained when they were reared on ryegrass stems and leaves. Rearing on floral spikelets beginning with third-instar nymphs resulted in 92% adults, whereas third-instar nymphs reared on stems and leaves produced no adults. These results showed that ryegrass could serve as a reproductive host for plant bugs when it flowered during late April and May. Application of the herbicide in March, when ryegrass was not in flower, resulted in no significant increases in plant bug populations on wild hosts (mainly ryegrass) during April and May in 2 yr of the field study.

Throughout 1994-2000, adult beet armyworm, Spodoptera exigua (Hubner) populations were monitored in the delta and hill regions of Mississippi using pheromone traps. Significant differences in the mean number of moths trapped were found among different geographical areas of the state. A trend was observed where the greatest number of moths was found in the Mississippi Delta, located in the western region of the state. The lowest number of moths was found in the hills located in the eastern region of the state. An annual profile of beet armyworm populations in the western section of the Mississippi Delta also revealed that wide-scale immigration of this pest typically begins at 200 Julian days (mid-July). This date could be used as a benchmark to determine when and if population levels are high enough to have the potential to cause economic damage to crops in the Mississippi Delta.

The boll weevil, Anthonomus grandis grandis Boheman, probably arrived in the United States near Brownsville, Tex., about 1892. In the next 30 years, this pest thundered across the U.S. Cotton Belt, leaving in its path destruction and devastation, causing shifts in agricultural production and social structure of the real South, and in reality shaping the early development of the profession of entomology in the southern states. Through the efforts of hundreds of dedicated people, the total elimination of this costly pest from within the United States borders is on the near horizon. It has not been an easy battle over the past 40 years, primarily because of the biological capabilities of the boll weevil itself, but also because of politics, misunderstandings, and often misguided efforts of scientists, environmentalists, and the public. This report chronicles the adventure from 1892 to the present and provides insight into the capabilities of the insect, remarkable scientific accomplishments, and political challenges.

More boll weevils, Anthonomus grandis Boheman, were captured after 20 May in 1995–1997 in grandlure-baited traps 1–5 km from cotton in Washington County, MS, than in traps near cotton. Even though few weevils were trapped from first bloom to mature boll (about 1 July to 18 August), >5 times as many weevils were captured in traps 1–5 km away from cotton than in traps near cotton. This suggested that competition from male weevils feeding in cotton as well as cotton odors may have masked late-season overwintering emergence. These results further suggested that overwintered weevils continue to emerge in low numbers into August, and that considerable movement of weevils (both overwintering and reproductive) occurred throughout the growing season. Numbers of overwintered weevils trapped from 23 March to 29 June 1996 were only 5% of those trapped during the same period in 1995. However, numbers captured from 18 August to 28 December 1996 equalled those for the same period in 1995, which showed the powerful ability of the boll weevil to rebuild from low numbers in a single season. Boll weevils responding to traps were slightly >50% females before July 1, increased to almost 100% females in midseason, and declined to slightly >50% females again in late season. Over 5,000 boll weevils were examined in 1996 for pollen grains in the midgut throughout the year, and over 300 plant taxa were identified. A majority of the taxa occurred in the Anacardiaceae (sumac), Asteraceae (sunflower), Cheno-am (Chenopodiaceae and Amaranthaceae, goosefoot, and pigweed), Fagaceae (oak), Malvaceae (mallow), and Poaceae (grass) families. These results indicated that noncotton hosts were potentially important in survival of boll weevils throughout the year but not a factor in reproduction, because boll weevils have been found to reproduce only on cotton in the Mississippi Delta.

Comparison of Bacillus thuringiensis transgenic and nectariless cottons with non-B. thuringiensis commercial varieties >2-yr showed no significant differences in number of beneficials, bollworm [Helicoverpa zea (Boddie)), and tobacco budworm [Heliothis virescens (F.)] eggs, fruiting sites per plant, and percentage square set. Significantly more tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), and percentage of crazy cotton were observed in B. thuringiensis 757 (Coker 312 background in 1994) and in Coker 312 variety in 1995 compared with other varieties, suggesting no effect of B. thuringiensis gene insertion in cotton on the number of tarnished plant bugs. Transgenic cotton had significantly fewer bollworms and budworms, cabbage loopers [Trichoplusia ni (Hobner)], and percentage of damaged squares than the other varieties, 75% as many beet armyworms [Spodoptera exigua (Hobner)), and had no effect on fall armyworm [Spodoptera frugiperda (J. E. Smith)]. The transgenic character itself did not cause an increase of any insect population, but consultants and producers are encouraged to monitor other insect pests, especially boll weevil, Anthonomus grandis grandis Boheman, and tarnished plant bug. These pests may cause economic damage when fewer or no sprays are used for bollworm and budworm in cotton. Nectariless MD51 had fewer plant bugs than other varieties both years, but also lower yield. These results suggest transgenic cotton is a useful tool in tile management of certain lepidopterous pests.

Fungicides used commercially for control of cotton seedling diseases were evaluated under field conditions during a 3-yr period for their effects on the prevalence of the entomopathogenic fungus Neozygites fresenii (Nowakowski) Batko in the cotton aphid, Aphis gossypii Glover. The susceptibility of N. fresenii to the fungicides varied. Carboxin significantly reduced N. fresenii prevalence during the early season. Furthermore, A. gossypii population levels were significantly greater during the 1993 field test in plots treated with carboxin. In some cases etridiazole and metalaxyl also significantly reduced N. fresenii prevalence during the early season. Conversely, N. fresenii prevalence was generally equivalent to or greater in the fungicide-treated plots than in the control plots during the late season. Although numerous biotic and abiotic factors (that is, environmental or artificial or both) also influence fungal prevalence in field situations, this appears to be the 1st demonstration of reduced entomopathogenic fungal prevalence caused by the application of a granular fungicide at planting. Biological and cultural implications are discussed.

A series of experiments was conducted to determine the most effective traps, lures, and kill strips for deploying against the boll weevil, Anthonomus grandis grandis Boheman. The results indicated that Hardee traps or the Hercon Boll Weevil Scout baited with either of two 2-wk lures were comparable and the best combinations for use in boll weevil monitoring and eradication programs. Either kill strip used in traps was equally effective and is recommended for convenience in servicing traps.

DES 119 cotton, Gossypium hirsutum L., and a smooth-leaf isoline were monitored, for cotton aphid, Aphis gossypii Glover, densities and effects on yield in aphicide-treated and untreated plots. The interactions of cotton genotype and aphicide treatment regime were significant for aphid density and cotton yield. Aphids caused a yield loss (≈140 kg lint per hectare) in DES 119 cotton when it was not treated with aphicide. No yield differences were observed between aphicide-treated and untreated plots containing the smooth-leaf isoline of DES 119. Yields for DES 119 with aphicide, the smooth-leaf isoline without aphicide, the smooth-leaf isoline with aphicide, and DES 119 without aphicide were 1105.0, 996.3, 971.0, and 964.0 kg lint per hectare, respectively. DES 119 treated with aphicide yielded more cotton than each of the other treatments. No differences were observed in the densities of, nor damages caused by, other cotton pests, which could account for yield losses that we attributed to cotton aphid. The data also indicated that the smooth-leaf isoline of DES 119 offers substantial resistance to cotton aphid. Thus, high-yielding, smooth-leaf cotton lines that do not respond to aphicide treatments might be viable alternatives to currently used chemical approaches, to cotton aphid management.

Inbred crosses through three generations and reciprocal backcrosses through five generations using Helicoverpa zea (Boddie) from Stoneville, MS, and H. armigera (Boddie) from Tashkent, Russia, were studied for backcross sterility. A high percentage of mated females reproducing indicated a high degree of genetic compatibility between the two species. No indication of backcross sterility was detected in these studies.

A 9.6-km diam area in the intensive cotton-growing region of the Mississippi Delta was treated with an entomopathogenic virus to determine the effect on populations of adult tobacco budworms, Heliothis virescens (F.), and bollworms, Helicoverpa zea (Boddie), emerging from early season weed hosts. Four aircraft were used to treat ≈ 7,106 ha during 24–28 April at a rate of 100 larval equivalents per ha. Emergence data from cages placed over treated and untreated areas indicated that virus treatments reduced tobacco budworm emergence by 80.6% and bollworm emergence by 46.2%. During the emergence period, tobacco budworm traps in the area surrounding the treated area averaged 11.4 moths per trap per night. Average trap capture per trap per night in the center (6.4 km diam) of the treated area was 6.4 moths, a reduction of 43.9% compared with the untreated area. Correspondingly, reduction in trap counts for bollworm in the center was 21% when compared with the untreated area.

The seasonal abundance patterns of the cotton aphid, Aphis gossypii Glover, and its complex of biological control agents on six cotton cultivars differed among cultivars during much of the growing season. Differences in aphid populations among cultivars were >3-fold during the period of peak aphid abundance. Lower aphid densities were found on cultivars exhibiting the smooth-leaf character. Parasitism and predation may have reduced cotton aphid population growth early in the season. Entomopathogen infection was the primary cause of an aphid population reduction that occurred during the week after peak aphid abundance, and continued pathogen activity combined with predation maintained aphids at a low density for the remainder of the season.

The effect of parasitoid age and two instars of the host Helicoverpa zea (Boddie) were investigated for the endoparasitoid, Microplitis croceipes (Cresson). Third and fourth instars of H. zea were exposed to three different age ranges (3 to 5, 6 to 8, and 12 to 15-d-old) of mated adult female M. croceipes. No significant differences were shown in rate of parasitism regardless of parasitoid age or host instar. Significant differences (P < 0.05) were found between parental age and adult wasp emergence, sex ratio, and number in pupal stage entering diapause. Six to 8-day-old parasitoids parasitizing third instar hosts yielded the highest percentage of adult emergence (47.5 ± 14%; X̄ ± SD), the highest percentage of females (79%), and the lowest percentage (4.5 ± 6%; X̄ ± SD) entering diapause during the test.

A 2-yr study of the effect of in-furrow application of aldicarb, disulfoton, carbofuran, and acephate on the level or frequency of resistance in the cotton aphid, Aphis gossypii Glover, revealed an increase in tolerance of survivors to bifenthrin (pyrethroid) and endosulfan (CHHC), two commonly used aphicides. With the exception of a low dose of acephate, all granular insecticides applied at planting increased the tolerance of surviving field-collected aphids and their offspring to both of these pesticides. Because alternative control measures may contribute more to the resistance problem than the use of granular insecticides at planting, the use of granular insecticides is still recommended as one of the steps to be taken in resistance management.

Heliothis virescens backcross moths are most effectively released in wide-area release programs from pupae placed in the field prior to moth emergence. A significantly greater moth emergence was obtained in the field from unharvested pupae in rearing trays than was obtained from harvested pupae. Mating, oviposition, and egg viability of emerged female moths were not adversely affected by handling procedures. Moths released from emergence containers were recovered in the most distant trap, 5.5 km, from the release point. However, the greatest number of released moths was captured in pheromone traps within 1.7 km of the release point.

We investigated genetic variability in oviposition preference between and within colonies of the cotton bollworm, Helicoverpa zea (Boddie), originating from southern Texas, central North Carolina, and the Mississippi Delta. We established preference hierarchies using choice tests in which terminals of pubescent and glabrous lines of cotton and soybean were offered. Preferences of populations were compared using MANOVA techniques. The quantitative genetic technique of half-sibling analysis was used to estimate within-colony heritabilities of oviposition preference and genetic correlations between preference and pupal weight, developmental time, longevity, and fecundity. The Mississippi colony showed a significantly stronger preference for cotton than the other colonies, which did not differ significantly from one another. This difference is probably genetically based and could be related to the relative abundance of cotton coupled with the lack of host-crop heterogeneity in the Mississippi Delta region relative to the colonies originating from Texas and North Carolina. Half-sibling analyses detected significant levels of heritable genetic variability in oviposition preference in the Mississippi colony. In addition, a positive genetic correlation was found between proportion of eggs laid on hairy cotton and fecundity. These results suggest the potential for evolutionary change in oviposition preference by the population of H. zea in the Mississippi Delta. However, caution should be used in extrapolating results of this small-scale laboratory study to the field.

Since 1992 insects have consistently cost cotton, Gossypium hirsutum L., producers US$ 0.8–1.6 billion annually in direct management costs and associated yield losses (Beltwide Cotton Conference Reports, National Cotton Council, Memphis, TN). In the mid-1980s and continuing to the present, cotton entomologists and producer organizations realized the difficulty in managing all of the major complex and persistent cotton insect problems on a local basis (Henneberry and Phillips 1996). In an attempt to overcome these challenges, management programs were organized on an area-wide concept rather than on an individual field basis. These programs were inspired by the amazing success of eradicating the screwworm fly, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) from the southeastern United States (Knipling 1960a). In addition, the propensity for development of insecticide resistance in several cotton insects, especially boll weevil, Anthonomus grandis grandis Boheman (Roussel and Clower 1955; Walker et al. 1956; Fye et al. 1957; Smith 1998), tobacco budworm (TBW), Heliothis virescens F. (Elzen et al. 1992; Elzen and Hardee 2003), tarnished plant bug, Lygus lineolaris (Pali-sot de Beauvois) (Snodgrass and Elzen 1995; Snodgrass 1996) and sweetpotato whitefly, Bemisia tabaci (Gennadius) (Prabhaker et al. 1996) created an urgency for development of improved management techniques for cotton insects. We report herein, case histories of attempts to manage six cotton insects in an area-wide system.

Examination of commercial Cry1Ac transgenic Bacillus thuringiensis Berliner (Bt) cotton varieties (Bollgard, Monsanto, St. Louis, MO) and an experimental Cry1Ac + Cry2Ab transgenic Bt cotton variety (Bollgard II, Monsanto) for lepidopteran field efficacy was conducted during the 2000 growing season. In addition, a commercially available (Envirologix, Portland, ME) quantification assay (ELISA) was used to measure and profile the expression levels of Cry proteins in two of these varieties ['DP50B, Bollgard'; 'DP50BII, Bollgard II' (DeltaPine Land, Scott, MS)]. Populations of beet army worms, Spodoptera exigua (Hübner), and soybean loopers, Pseudoplusia includens (Walker), were significantly lower (P0.05) in Bollgard II plots compared with Bollgard. Population numbers for fall army worms, Spodoptera frugiperda (J. E. Smith), and salt marsh caterpillars, Estigmene acrea (Drury), were lower in Bollgard II plots compared with Bollgard but means did not differ significantly (P0.05). Single and dual-toxin genotypes remained superior (P0.05) compared with conventional cotton against the tobacco budworm, Heliothis virescens (F.). The addition of Cry2Ab had no significant (P0.05) impact on Cry1Ac expression in Bollgard II compared with Cry1Ac expression in Bollgard. Furthermore, throughout the season Cry2Ab was present at much higher levels in the plant compared with Cry1Ac for Bollgard II plants. Possible species-specific reasons for increased efficacy of Bollgard II over Bollgard are discussed.

Colonies of A. gossypii were assayed for insecticide tolerance using a leaf-dip test. Two colonies represented collections made from areas of control failures in Stoneville, MS, and Lawrence County, AL, and were reared in the greenhouse on DES 119 cotton 3 mon before a susceptible colony was established from aphids collected from Earlimart, CA. Cotton terminals were swirled 15 sec in water (control) or in a solution of formulated insecticide at a concentration causing approximately 90% mortality of susceptible insects: Lorsban 300 ppm, Thiodan 300 ppm, Capture 10 ppm, Metasystox-R 100 ppm, and Bidrin 100 ppm. Terminals were allowed to dry 45 min, placed in water wicks, and infested on leaf undersides using ventilated clip cages. Infested terminals were held at 80° F, 50% RH, and 14:10 L:D. Four replications (1 replication = 1 terminal) of 10 wingless adults/replication of similar size and color (green/black) from each colony were run. Mortality was determined 24 h later. Additionally, Lorsban and Thiodan were assayed using a laboratory spray table at field rates (1.0 lb and 0.33 lb (AI)/acre, respectively), calibrated to deliver 6 gal/acre (30 psi, TX 6 nozzle, 2 mph). Six replications of 10 aphids/replication were run for each treatment; caging, holding conditions, and test duration were the same as for dip bioassays.

An analysis of a pheromone trapping system was performed to study the possibility of theoretically estimating the efficiency of a boll weevil pheromone field trapping system. Release-capture data for a single trap were used to establish percent capture versus distance from the trap. A computer simulation model predicting trapping efficiency showed that results are very sensitive to the responsiveness characteristics of the population. Theoretical results also showed sensitivity to trap spacing and identified some specific research needs.

Three slow-release preparations of grandlure, the synthetic pheromone of Antonomus grandis Boheman, were evaluated in the field at 3 locations in Texas and Mississippi, to compare their relative attractancy to adult weevils during the period of fall dispersal. All 3 formulations, at both low (3 mg per unit) and high (12 mg per unit) doses of grandlure, were more attractive throughout 14-day test periods than were caged males or fast-release formulations that were both replaced at 2-day intervals. The combined results of field tests at all locations, and of laboratory analyses of weathered samples, suggested that a physical-barrier system might yield more consistent results, but no single formulation was decidedly superior to the others. Tests demonstrated also that slow-release formulations could be used effectively in the different types of boll weevil traps currently in use.

Field tests of variations in concentrations of the 4 components of grandlure, the pheromone of the boll weevil, Anthonomus grandis Boheman, showed that increased percentages of alcohols (and thereby decreased percentages of aldehydes) significantly improved performance. One alcohol was more important than the other in determining activity, but both alcohols must be present with small amounts of the aldehydes for maximum effectiveness. Captures of boll weevils increased only slightly when doses were increased above 3 mg.

Grandlure-baited in⋅field traps used at the rate of 10/acre captured 76% of a population of overwintered Anthonomus grandis Boheman estimated to number ca. 25/acre that emerged between the time cotton was planted and the time the plants produced pinhead squares. A combination of in-field traps and insecticides captured or killed 100% of the emerging overwintered weevils during the 23 days between the pinhead square stage of plant growth (June 13) and July 6. The traps alone captured ca. 96% of a late emerging population of ca. 1 boll weevil/acre during July 6–31. The problem of clumping of F1 and F2 progeny proved to be an important factor in the efficiency of the traps.

The response of Anthonomus grandis Boheman to colored lights in the laboratory confirmed that the 500–525-nm region of the spectrum has the greatest attraction. Poor response to red was noted in the laboratory and in the field. In the field, the response of both early- and late-season boll weevils to the traps increased as the intensity of reflected light was increased and also when the pigment more closely approached the 500–525-nm region of the spectrum. The greatest response was obtained with highly reflective daylight fluorescent pigments that had this spectral characteristic.

Field inspections and wing traps containing live male Anthonomus grandis Boheman were used in 1968 to study the seasonal movement of boll weevils near the High Plains of Texas. Peak populations of overwintered weevils occurred in cotton fields within 4-5 weeks after planting. Movement of boll weevils began early in the spring before cotton was planted, decreased greatly during midsummer, and increased again to a very high level late in August. Relatively large numbers of weevils were captured in both the spring and fall at distances more than 6 miles from cotton.

In the spring of 1969, male-baited traps for Anthonomus grandis Boheman were placed around ca. 4000 acres of cotton in a large-scale field test in Monroe County, after completion of a voluntary grower-sponsored reproduction-diapause control program the fall of 1968. The few fields that had not been treated produced a population of weevils which varied from field to field. Where over wintered boll weevils numbered less than 5 per acre, the trap efficiency was estimated to be 93%, but it dropped to 21% when the populations averaged about 300 weevils/acre. Differences in the number of over wintered boll weevils collected per trap were not significant when 1, 2, 4, and 8 traps per acre were compared. However, significantly more over wintered boll weevils were found in the fields with 8 traps per acre than in fields with 2 traps per acre. Inter field movement of over wintered weevils from the fields that had not been treated appeared to be restricted to those fields that shared over wintering sites with the untreated fields. Some fields were treated with insecticides in July for control of 1st-generation boll weevils, but many fields did not require treatment until early August.

The feeding activity, mating frequency, attraction, sexual response, and mortality of normal Anthonomus grandis Boheman were compared with boll weevils irradiated with 6388 or 12,775 rad of Co60 gamma radiation. The irradiated weevils equaled normal weevils in each aspect of behavior for at least 5 days posttreatment. However, by the 7th day posttreatment, all these activities had started to decline in the treated weevils and all irradiated weevils were dead by the end of the 2nd week. Thus, irradiated boll weevils may be effective in a program involving the release of sterile insects, but the releases would have to be made at least weekly and preferably every 5 days.

The definite preference of over wintered and late-season Anthonomus grandis Boheman for male weevils compared with that for fruiting cotton suggests that the pest may be less attracted to weevil-free cotton than to cotton containing male weevils that have found the plant by random flight or because of a short-range response to a plant attractant. Traps baited with live male weevils or with a synthetic male pheromone may thus prove a possible new method of control and/or eradication of boll weevils and a valuable method of making surveys to detect small, incipient populations of boll weevils formerly not easily surveyed.

Both sexes of Anthonomus grandis Boheman responded in the field to a synthetic pheromone mixture, grandlure. A wick-type formulation of grandlure containing glycerol, water, polyethylene glycol, and methanol was over 80% competitive as an attractant for 7 days with caged, live males fed cotton squares (flower buds) once or twice a week.

Three years of field studies showed that the initial deposit and the rate of decomposition of residues of insecticides vary with the forage species. More insecticide was deposited upon application and disappearance of residues was slower on timothy and alfalfa than on birdsfoot trefoil and red clover. The differences found were frequently significant. Differences in residue levels on different species are important in making practical recommendations for insect control on forages.

Laboratory studies with the sex attractant of the boll weevil, Anthonomus grandis Boheman, confirmed previous findings that the female aggressively seeks the pheromone-emitting male. In both sexes, peak activity occurred when the weevils were 4–6 days old. When I sex was 4–6 days old and the other was less than 2 days old, the males were mostly unattractive and the females mostly unresponsive. Females responded to a single male, but response was significantly greater to 5, 10, or 25 males. Virgin males were twice as attractive and virgin females were 3 times as responsive as mated males or females. Males sterilized with apholate were about half as attractive to virgin females as untreated males when both were fed on laboratory diet but were equally attractive when both were fed on fresh cotton squares (flower buds). Comparisons between laboratory (medium-reared) and field (square-reared) male weevils, each fed cotton squares or laboratory diet, indicated a greater importance of food rather than strain in determining female response.

Optimum conditions were determined for capturing. Anthonomus grandis Boheman in traps baited with males. Metal wing traps were painted daylight fluorescent yellow over a white undercoat (about 4×6-m. wings × 9-in. base) and were coated With an adhesive. Traps were baited with male boll weevils which were held in a container with a single layer of screen and placed at heights of 1–3 ft above ground around a cotton field adjacent to overwintering sites. This system, or a slight modification, would be useful in subsequent surveys and for control or possible eradication of the boll weevil with traps.

A substance that deters feeding of the boll weevil, Anthonomus grandis Boheman, was found in the filtrate of a water extract of tung meal, a byproduct of the process of extracting oil from the seeds (nuts) of the tung tree, Aleurites fordii Hemsl. The same substance (or a related substance) was present in more concentrated form in tung oil. The deterrent effect of the substance (s) was greater than that produced by a water extract of calyxes From buds of Rose-of-Sharon, Hibiscus syriacus L. The substance is readily soluble in water, resistant to moderate and volatilizes slowly. A 2- to 15-fold decrease occurred in the number of feeding punctures made by boll a weevils (compared with the controls) when cotton squares (buds) were dipped in a filtrate of water homogenized with tung meal that had been expeller-extracted. This deterrent effect was less when a filtrate of a homogenate of water and meal extracted by using hexane as a solvent was used and was greater when pure tung oil was used. In studies of serial dilution, the increase in deterrent effect was directly proportional to the increase in concentration of the filtrate. Antennectomy of boll weevils did not reduce the deterrent effect.

Collections from wing traps baited with male Anthonomus grandis Boheman and from ground trash were used to study overwintering weevil populations in various vegetational habitats in the Rolling Plains of Texas, 1969–71. The primary overwintering habitats were “motts” of sand shinnery oak; communities of woody plants dominated by such species as sand shinnery oak, chinaberry, and poplar; and dense rangeland stands of mesquite. Populations in hibernation varied among specific vegetational sites within the habitats, and hibernating populations were concentrated largely in the proximity (≤½ mile) of cotton fields. Major winter mortality occurred within the hibernating sites during late January or early February.

Techniques for isolating the sex attractant of the boll weevil Anthonomus grandis Boheman, were studied. Aeration of live insects, extraction procedures, column chromatography on Florisil® and Carbowax 20M® coated silica gel, and steam distillation of male and mixed weevils and of fecal material are described. Bioassays of the fractions obtained indicated that steam distillation of male or mixed insects or fecal material is the preferred method of isolating the attractant.

Residues of several chlorinated insecticides have been found to persist in the ppb range at harvest following normal control practices for insect pests of alfalfa and other forages. The studies reported herein were undertaken to determine the absence or presence in milk of two of these materials fed at such levels to dairy cows for extended periods of time. Technical heptachlor epoxide and Telodrin® (1,3,4,5,6,7,8,8- octachloro-l, 3,3a, 4, 7, 7a-hexahydro-4, 7-methanoisobenzofuran) were fed for 28 days to lactating dairy cows at levels of 5 and 20 ppb of their average daily roughage intake. Milk samples were taken at regular intervals before, during, and after insecticide feeding and analyzed for residues by gas chromatography. Small but measurable quantities of both insecticides were detectable in milk as early as 5 days after initiation of insecticide feeding and as late as 10 weeks after termination of feeding.

Infestations were not found in 17 of 34 cotton fields in west Texas in which wing traps baited with male Anthonomus grandis Boheman, were used. Moreover, adult weevils were found in only 7 of the 17 fields, and populations of boll weevils did not reach economically damaging levels in any of the fields. However, traps around all 34 fields captured boll weevils in low to moderately high numbers. The traps suppressed more than 80% of the boll weevils, with traps placed around the fields in tiers, and used in conjunction with trap plots treated with aldicarb giving the best results.

When female Anthonomus grandis Boheman in large plots or cages were captured in 12 kinds of traps, all baited with males or various extracts of males, a small Stikem®-coated plywood trap and a Plexiglas® screen funnel trap proved to be the most efficient designs. Few or no females responded to empty traps (controls), and a preponderance of captured females came to the traps from downwind. Thus, a wind-borne sex attractant is produced by male boll weevils. The captures of females indicated a preference for live males over extracts of males of 1.8:1 when the comparisons were made on different days and of 6.2:1 when they were made on the same day.

Tests were made to determine the presence of feeding stimulants and attractants for Anthonomus grandis Boheman in aqueous extracts of host and nonhost species of the family Malvaceae including cotton, Gossypium hirsutum L. The host plants found infested most frequently in nature generally contained the highest concentrations of feeding stimulant and attractant. Also, all known plants except Hibiscus syriacus L. attacked in nature by the boll weevil contained gossypol. Thus, plants containing gossypol seem preferred, but its presence does not appear to be an absolute requirement for host acceptability. Of the species tested, Cienfuegosia sulphurea (St. Hill.) Garki and Thespesia populnea (L.) Soland ex Carrea seemed the most suitable wild hosts next to cotton. H. syriacus again was not preferred. However, late in the season when it is near cotton it is sometimes attacked. For this reason, and because of its wide geographical distribution and general abundance as an ornamental throughout the Cotton Belt, it is the most important of the alternative hosts to consider in any future eradication programs against the boll weevil.

In the first large-scale tests with sprays of chemosteriants against any insect pest, apholate applied to the cotton in 21½-acre screened cages at rates of 1, 2, or 4 pounds per acre for control of Anthonomus grandis Boheman suppressed populations compared with an untreated check whether the initial infestations were begun with virgin or mated pairs. Hempa, at a rate of 2 lb per acre, was ineffective. At 4 lb per acre, apholate reduced production of squares compared with an untreated check, but the toxicity of this compound was too great for general use. Since the technique proved effective, other less hazardous chemosterilants are being sought.

Results of studies of female Anthonomus grandis Boheman made to determine the influence of biological factors Oil its response to male sex pheromone indicated that: (1) laboratory-reared males were as attractive and females were as responsive as native weevils if they had access to cotton squares (flower buds) as food; (2) increased attraction of isolated males over grouped males was substantiated; (3) males in close proximity to females were no more attractive to females than isolated males; (4) the lack of response of recently mated females emphasized the need to capture females in traps before they mate with free, competing males; (5) sterilization of males with apholate or irradiation did not significantly decrease their attractiveness compared with untreated males: (6) females responded to males as many as 3 times and from distances of as much at 82 m; (7) the high percentage of females captured in traps baited with males in the absence of competing males, and the low percentage captured with males in traps in an infested plot containing large numbers of competing males suggest that the sex pheromone might have a major role in suppressing weevil populations in areas where populations are extremely low. for example, in the spring after an effective fall diapause-control program has substantially reduced the number of over wintering boll weevils.

From June 17 through August 26, 1964, 11 weekly releases of apholate-sterilized male boll weevils, Anthonomus grandis Boheman, were made in 9 cottonfields, (15.8 acres) that had been treated with insecticides the fall of 1963 to reduce the population of diapausing weevils. These weekly releases ranged from 3270 to 26,620 sterile weevils per acre (an average of 8200 per acre). Migrant weevils entering the release zone from other areas may have caused the program to achieve population suppression rather than eradication, though the release zone was surrounded by a 120-acre zone that had received the same fall treatment and was treated intensively with insecticides in 1964 and by another 115-acre buffer zone that was treated with insecticides in 1964. However, the apholate sterilized only an average 95.8% of the weevils and caused a substantial reduction in mating competitiveness. The release of the sterile males against the low-level population achieved by the 1963 fall applications reduced the number of oviposition-punctured squares compared with the number in the other 2 zones. Also the percentage of infertile eggs, the numbers of live immature and adult weevils per acre in fruit, the numbers of adults on plants and in hibernation sites, the numbers of overwintered adults, and the levels of infestation during the 2nd year or season after the releases were terminated were considerably lower in the release zone than in the zone treated intensively with insecticides.

The attraction, feeding, and oviposition of Anthonamus grandis Boheman on the dioecious plant Hampea sp., was compared with Deltapine Smoothleaf cotton by laboratory bioassay. Plant parts and extracts of the male plant were comparable to cotton in attractiveness and stimulation of feeding, but extracts of female buds and capsules were significantly less attractive than extracts of male buds and cotton buds. A volatile repellent(s) in the extracts of the female buds and capsules probably masked the attractive material(s) present, but after storage at 5°C these extracts became as attractive as extracts of the male plant and of cotton freshly prepared from buds stored at −90°C. Also, female buds contained significantly less feeding stimulant than male buds and cotton buds. This lesser concentration plus the volatile repellent produced a high degree of resistance of the boll weevil (nonpreference) to female buds and capsules.