• Comparative Development and Reproduction of Pink Bollworm on Upland and Pima Cotton Cultivars

      Naranjo, Steven E.; Martin, Jeanette M.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Development and reproduction of pink bollworm were studied in relation to four cotton cultivars. Larval developmental times were shortest on pima cotton and longest on a resistant okra-leaf variety (WC-12NL). Prepupal and pupal developmental times were generally unaffected by cultivar. Larval establishment and survival did not differ significantly among cultivars. Female moths laid fewer eggs on pima bolls early in the season and fewer eggs on the okra-leaf cultivar on a season -long basis in comparison with two conventional upland cultivars. Fecundity of adults from the four cultivars varied little but was generally highest in adults from larvae reared on pima cotton. Results have implications for predicting pink bollworm phenology and population development in different cultivars.
    • Control of the Sweetpotato Whitefly by Insect Growth Regulators

      Bartlett, A. C.; Lewis, L. J.; Hunter, B. A.; Silvertooth, Jeff; Bantlin, Marguerite; USDA-ARS-Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Two newly developed insect growth regulators were tested at two dose levels for control of the sweetpotato whitefly on cotton. The two chemicals showed some promise for control although the dose rate and application schedules were not optimal and plot sizes were too small to show a decrease in cotton stickiness or sugar content due to the treatments. In these tests a chitin synthesis inhibitor was more effective in controlling immature stages than a juvenile hormone mimic.
    • Cotton Yields as Affected by Pheromone Treatments for Pink Bollworm

      Sears, John; Hood, Larry; Moore, Leon; Winans, S. Sherwood; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Cotton fields treated with Gossyplure pheromone for pink bollworm, Pectinophora gossypiella (Saunders), management were surveyed to evaluate the effectiveness of the pheromone treatments. Fields were randomly chosen within four separate areas of the Parker Valley and Palo Verde Valley and sampled weekly for presence of pink bollworm (PBW ) larvae. No differences were found in cotton yields between fields treated with pheromone and non- treated fields.
    • Effect of Plant Growth Regulators Under Short-Season Conditions on Pink Bollworm Populations, Cotton Yields and Defoliation

      Chu, Chang-chi; Henneberry, Thomas J.; Bariola, Louis A.; Deeter, Brian; Silvertooth, Jeff; Bantlin, Marguerite; USDA-ARS, Western Cotton Research Laboratory, Phoenix, AZ; Rhone Poulenc Ag Co., Wickenburg AZ (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Plant growth regulators (PGR's) [thidiazuron (Dropp®) N-phenyl-N' -1,2,3-thiadiazol -5 ylurea, 50% wettable powder, Nor-Am Agricultural Products, Inc., Naperville, IL, and ethephon (Prep®) a- chloroethyl phosphonic acid Rhone - Poulenc Ag Co., Research Triangle Park NC] were applied to reduce late- season fruiting forms as a source of host material for developing overwintering PBW populations. Combinations of ethephon and thidiazuron or thidiazuron alone were more effective than ethephon alone for reducing late -season immature green bolls. None of the PGR's alone or in combination affected yields. Highest rates of defoliation occurred after applications of thidiazuron. The data suggest that temperature thresholds for highest plant growth regulator activity occur.
    • Effect of Plant-Derived Oils on Sweetpotato Whitefly on Cotton

      Butler, G. D. Jr.; Coudriet, D. L.; Henneberry, T. J.; Silvertooth, Jeff; Bantlin, Marguerite; USDA-ARS-Western Cotton Research Laboratory, Phoenix AZ (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Cottonseed oil applied to cotton repelled sweetpotato whitefly (SPW) adults up to 8 days in greenhouse tests. Soybean oil (5 %) resulted in reduced numbers of adults and numbers of eggs laid. SPW egg hatch was reduced 84% after treatment with 10% crude cottonseed oil solutions as measured by the number of first instar larval emergence. Also, numbers of whitefly larvae were reduced 99, 91 and 83% on day 6 following treatment with 10% cottonseed oil, S and 1.5% soybean oil, respectively. Negligible plant leaf phytotoxicity occurred from the plant-derived oil treatments.
    • Fat Content and Reproductive Condition of Migrating and Dispausing Boll Weevils in South Carolina and Arizona

      Leggett, J. E.; Silvertooth, Jeff; Bantlin, Marguerite; USDA-ARS-Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Overwintered female boll weevils, Anthonomus grandis Boheman, collected in grandlure- baited traps were significantly leaner than weevils taken from winter habitat. Weevils that emerged from naturally infested cotton bolls tended to be fat as adults regardless of subsequent adult diet, but adult diet can affect gonadal development. Weevils that emerged from bolls in 1975 in South Carolina had a higher winter survival rate and emerged from winter habitat earlier than the total population. Migrant weevils appear to be mainly colonizers that have some body fat and medium size gonads. The physiological condition of migrants was fairly consistent over time and location in South Carolina but not in Arizona. The time of migratory flight was related mainly to plant maturity and population levels in South Carolina. Weevils collected from cotton plants in South Carolina and Arizona had significantly more body fat than weevils trapped at the cotton field but oogenesis was variable between the two locations.
    • Field Performance of Cotton Genetically Modified to Express Insecticidal Protein from Bacillus thuringiensis

      Wilson, F. Douglas; Flint, Hollis M.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Five transgenic lines of cotton, Gossypium hirsutum L., carrying the delta-endotoxin gene from Bacillus thuringiensis Berl., and two control cultivars, Coker 312 (the parent stock) and MDS1N (an adapted nectoriless line) were evaluated at the Maricopa Agricultural Centerfor resistance to attack by several insect pests and for agronomic properties. The transgenic lines were highly resistant to pink bollworm (PBW), Pectinophora gossypiella (Saunders), as shown by 90% fewer rosetted blooms, 96% fewer PBW recovered from incubated bolls, and 92% less seed damage than in the control cultivars. The transgenic lines were highly resistant to saltmarsh caterpillar, Estigmene acres (Drury), and beet annyworm, Spodoptera exigua (Hbn.), as shown by minimal damage to transgenic leaves and almost complete defoliation of control leaves. The transgenic lines were virtually immune to cotton leafperforator, Bucculatrix thurberiella Busch as shown by no apparent damage to transgenic leaves, and many mines, "horseshoes", and feeding areas on the control leaves. Compared to Coker 312, one transgenic line yielded more lint, and one yielded less. Four transgenic lines had higher lint percentages and all five had smaller bolls and were later maturing than Coker 312. Compared to MD51N, no transgenic line yielded more lint and one yielded less. All five transgenic lines had lower lint percentages, three had smaller bolls, and three were earlier maturing than MDS1N (USDA, ARS, Western Cotton Research Laboratory in cooperation with Monsanto Co. and Arizona Agricultural Experiment Station).
    • Inheritance of Resistance to Permethrin by the Tobacco Budworm, Heliothis Virescens (F): Implications for Resistance Management

      Watson, Theo F.; Kelly, Suzanne E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      A laboratory selected permethrin resistant strain of tobacco budworm. Heliothis virescens (F), was crossed with a susceptible strain to determine the nature of inheritance of the resistance. Crossing of these highly resistant and highly susceptible strains showed susceptibility to permethrin to be auto trial and incompletely dominant. Backcrosses of F₁ progeny with resistant males indicated either that more than one gene is responsible for the resistance in this strain, or that the strain was not homozygous for resistance. It is likely that more than one locus is influencing permethrin resistance. The crosses and backcrosses performed provided relevant information for resistance management in the field.
    • Microplitis sp. From Australia (Hymenoptera: Braconidae): Development in the Beet Armyworm and Adult Longevity in Relation to Temperature

      Butler, G. D. Jr.; Henneberry, T. J.; Silvertooth, Jeff; Bantlin, Marguerite; USDA ARS- Western Cotton Research Laboratory, Phoenix AZ (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      The effects of temperature on development and longevity of a Microplitis sp. from Australia on the beet armyworm, Spodoptera erigua (Hübner) was studied in the laboratory. Time of development ranged from 25 days at 15°C to 6.2 days at 27.5 °C. The parasite developed twice as fast as its beet armyworm host. Average longevities of male and female parasites were not significantly different.
    • Pink Bollworm Management in Pima and Upland Cottons: Planting Date and Termination Date Effects

      Terry, Irene; Silvertooth, Jeffrey; Summers, Carol; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Different planting and termination dates of Pima S-6 and Upland (Deltapine 90) cotton (Gossypium barbadense L. and hirsutum L. respectively) were tested for their effects on pink bollworm (Pectinophora gossypiella) infestations. Tests were conducted during 1989 and 1990 cotton seasons at the University of Arizona Yuma Valley Agricultural Experiment Station. Planting dates indicated little effect on early season infestations of pink bollworm for either cotton. However. irrigation termination had the greatest effect on late season infestations. In 1989. heat unit (degree day 12.8/30° C. lower and upper thresholds) accumulations were several days earlier than 1990, due to a very warm year. Pheromone trap counts indicated higher populations in 1989 than 1990; however. infestations in the field were similar between the years. Infestations dramatically increased during July through September, indicating that a longer cotton season with actively growing fruit, results in a continued population increase. The termination dates affected the amount of fruiting structures left in the field and thereby affected infestations of overwintering larvae in the field. Termination date had a dramatic effect on the % bolls infested with overwintering larvae and the density of overwintering larvae /m.
    • Pink Bollworms in 'Detapine 90' and 'Pima S-6' Cottons in Arizona

      Henneberry, T. J.; Chu, C. C.; Forlow Jech, L.; Silvertooth, Jeff; Bantlin, Marguerite; Western Cotton Research Laboratory, USDA ARS (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Pink bollworm (PBW), Pectinophora gossypiella (Saunders) infestations in Deltapine 90, Gossypium hirsutum L., and Pirna S-6, G. barbadense L., cotton bolls were initiated at about the same time during the cotton growing season. Male moth trap catches in gossyplure-baited Delta traps followed similar trends in both cottons throughout the season, but tended to be higher in Pima S-6 cotton than in Deltapine 90 cotton late in the season. Late crop termination (last irrigation 26 September) as practiced in Pima cotton production vs. earlier crop termination (last irrigation I September) as practiced in upland cotton production resulted in higher numbers of late- season immature green bolls, higher numbers of PBW larvae per boll and higher populations of diapause larvae at harvest time in Pima than occurred in the upland cotton cultivar. PBW seed damage was lower in the Deltapine 90 cultivar than in the Pima S-6 cotton cultivar. Deltapine 90 lint yield was higher than Pima S-6 lint yield.
    • Planting Date and Susceptibility to Pink Bollworm

      Brown, P.; Silvertooth, J.; Moore, L.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      The susceptibility of cotton to spring emergence of pink bollworm (PBW) was evaluated for a variety of planting dates in Pinal, Maricopa, LaPaz and Yuma counties using historical climate records and heat - unit -based models that predict PBW emergence and cotton development. Early planted cotton proved most susceptible to the PBW emergence, however, springtime weather conditions also played an important role in determining overall susceptibility. Growers wishing to incorporate planting date as one aspect of PBW management should keep abreast of early season weather conditions.
    • Residual Activity of Permethrin, Chlordimeform and Permethrin + Chlordimeform Against Susceptible and Resistant Budworm

      Watson, Theo F.; Kelly, Suzanne E.; Estesen, Betty J.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Cotton was sprayed with permethrin, chiordimeform and the permethrin-chlordimeform combination to determine residual efficacy against resistant (R) and susceptible (S) populations of tobacco budworm (TBW) and reciprocal crosses of the two populations. Permethrin alone gave excellent results against susceptible tobacco budworm for the entire 7-day test period. However, against the resistant strain the highest level of mortality achieved was 40% on the 1-day post -treatment residue; results with the S:R and R: S (♂:♀) crosses were generally intermediate. Chlordimeform gave poor and erratic kill unrelated to the residue period regardless of the strain of TBW. The combination resulted in mortality similar to that of permethrin alone with the susceptible strain hut generally greater than that with permethrin alone against the resistant strain. The combination resulted in high mortality in the crosses, particularly the R. S (♂:♀) cross.
    • Response of the Tobacco Budworm to Permethrin and Methyl Parathion in Arizona, 1977-1990

      Watson, Theo F.; Kelly, Suzanne E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Field populations of tobacco budworm. Heliothis virescens (F.). have been monitored annually since 1977 with topical applications of synthetic pyrethroid insecticides (primarily permethrin) and methyl parathion to detect changes in insecticide susceptibility. These data showed that LD₅₀'s fluctuated somewhat from year to year with permethrin. but with one possible exception. the fluctuations were not sufficient to change levels of expected control in the field. Field populations continue to show susceptibility to permethrin even though one Maricopa County population showed an increase in the LD₅₀ to 12.4 in 1988. Field populations continue to show resistance to methyl parathion and susceptibility to permethrin.
    • Reversion of Permethrin Resistance in Field Strains and Selection for Azinphosmethyl and Permethrin Resistance in Pink Bollworm (Lepidoptera: Gelechiidae)

      Osman, Abdelgadir A.; Watson, Theo F.; Sivasupramaniam, Sakunlala; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Rearing of two field strains (Maratha, Yuma) of pink bollworm. Pectinophora gossypiella (Saunders). from Arizona under conditions free of insecticides resulted in reversion of resistance (in adults) in four and five generations. respectively. to levels close to that found in the susceptible laboratory strain. Permethrin resistance in these field strains is unstable and is apparently in its early phase of development. Results suggest that monitoring of pink bollworm resistance in field strains reared in the laboratory should be performed in the F₁ generation. Subsequent selection studies were performed on both larval and adult stages to investigate the capacity of the pink bollworm to develop resistance in both life stages. Fourteen generations of selection of larvae and adults with azinphosmethyl produced 1.9- and 1.6-fold tolerance. respectively. in the adult stage. Sixteen generations of larval selection with permethrin generated 9.7-fold resistance in adults. while 14 generations of adult selection produced 8.8-fold resistance in adults. Azinphosmethyl evidently possesses a low degree of selectivity for development of resistance in pink bollworm adults. Selection of larvae with both azinphosmethyl and permethrin seemed to generate higher levels of tolerance in larvae than in adults.
    • Status of Pink Bollworm Resistance to Insecticides in Arizona

      Watson, Theo F.; Kelly, Suzanne E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Populations of pink bollworm. Pectinophora gossypiella (Saunders), from Yuma, Casa Grande, Marana and Safford were compared with that of a susceptible laboratory (USDA) strain relative to their susceptibility to permethrin. A limited comparison was made with azinphosmethyl. All field strains were significantly more tolerant to permethrin than was the USDA susceptible strain. A comparison of the USDA and Yuma strains using azinphosmethyl indicated no difference in susceptibility between the laboratory and field strains.
    • Susceptibility of Field Populations of Pink Bollworm (Lepidoptera: Gelechiidae) to Azinphosmethyl and Permethrin

      Osman, Abdelgadir A.; Watson, Theo F.; Sivasupramaniam, Sakunlala; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Responses of five field -collected populations of the pink bollworm. Pectinophora gossypiella (Saunders). from Arizona and southern California. were compared with those of a standard. susceptible -laboratory strain. Field strains showed less than twofold difference in response to azinphosmethyl at LD₅₀ but had variable levels (1.3- to 18.3-fold) of response to permethrin. Strains from Yuma and Phoenix (Arizona) and Westmoreland (California) had highest levels of resistance to permethrin.
    • Trap Crop Effectiveness in Community Boll Weevil Control Programs

      Moore, Leon; Watson, Theo F.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Trap crops, along with delayed uniform planting and pinhead square treatments, greatly reduced spring populations of overwintered boll weevils, Anthonomus grandis Boheman, in a Laveen. Arizona community -wide 1PM program in 1987. Thirty four trap crops. planted fifteen days ahead of the regular crop. had as many as 39536 damaged plants/ha before insecticide treatments were initiated. Five insecticide applications at 3 day intervals beginning at square initiation were used to destroy weevils before the trap crops were plowed under at the time pinhead square treatments were initiated in regular planted fields. Damaged square infestations were 2 to II times lower throughout the season in 1987 compared to 1986 while average lint yields per ha increased from a low of 941 kg in 1985 to 1345 kg in 1986 and 1506 kg in 1987.