BIOLOGY AND ECOLOGY OF COTTON PESTS EMPHASIZING MANAGEMENT OF BOLL WEEVILS

Goals / Objectives
Characterize aspects of boll weevil biology, ecology, and ethology that affect population dynamics with the aim of enhancing control. Establish properties of grandlure dosage, presentation, formulation, and environmental interaction as they relate to detection of boll weevils. Develop effective alternative strategies and techniques for suppressing and managing boll weevil populations, both on areawide and local scales, including special situations such as environmentally sensitive areas and organic farms. Establish the biology, ecology, behavior, and population dynamics of secondary and emergent arthropod pests, and develop strategies for their effective management.

Project Methods
Patterns of boll weevil dispersal between cotton fields and overwintering habitats will be established using large-capacity traps, and identification of weevils marked with rare earth elements or contaminated with pollen. The boll weevil's utilization of host plants, attractive host plant stages, and nutritional host plant value will be identified using pollen analysis and HPLC analysis of amino acids. Lethal doses and sublethal effects of malathion to boll weevils will be quantified by laboratory bioassays and assessed relative to weevil age, sex, reproductive development, and physiological condition. Temporal patterns and flight response of boll weevils captured in traps baited with standard and "super" formulations of grandlure will be established. Environmental impacts on pheromone release rates and lure longevity will be quantified using meteorological sensors and gas chromatography. Alternative boll weevil control tactics including bioactive and physical agents will be developed for integration into suppression and eradication strategies, including implementation in environmentally sensitive areas and on organic farms. Mechanical and chemical cotton stalk destruction and regrowth control strategies will be evaluated using remote sensing. Changes in the population dynamics of secondary and emergent pests during active boll weevil eradication will be established. Bioactive or physical agents will be evaluated as alternatives to conventional insecticides for management of secondary and emergent arthropod pests in cotton. The impact of Bt cotton production on the boll weevil eradication activities will be determined in field evaluations of secondary and emergent pest and beneficial insect populations.

Progress 10/01/05 to 09/30/10

Outputs
Progress Report Objectives (from AD-416) Characterize aspects of boll weevil biology, ecology, and ethology that affect population dynamics with the aim of enhancing control. Establish properties of grandlure dosage, presentation, formulation, and environmental interaction as they relate to detection of boll weevils. Develop effective alternative strategies and techniques for suppressing and managing boll weevil populations, both on areawide and local scales, including special situations such as environmentally sensitive areas and organic farms. Establish the biology, ecology, behavior, and population dynamics of secondary and emergent arthropod pests, and develop strategies for their effective management. Approach (from AD-416) Patterns of boll weevil dispersal between cotton fields and overwintering habitats will be established using large-capacity traps, and identification of weevils marked with rare earth elements or contaminated with pollen. The boll weevil's utilization of host plants, attractive host plant stages, and nutritional host plant value will be identified using pollen analysis and HPLC analysis of amino acids. Lethal doses and sublethal effects of malathion to boll weevils will be quantified by laboratory bioassays and assessed relative to weevil age, sex, reproductive development, and physiological condition. Temporal patterns and flight response of boll weevils captured in traps baited with standard and "super" formulations of grandlure will be established. Environmental impacts on pheromone release rates and lure longevity will be quantified using meteorological sensors and gas chromatography. Alternative boll weevil control tactics including bioactive and physical agents will be developed for integration into suppression and eradication strategies, including implementation in environmentally sensitive areas and on organic farms. Mechanical and chemical cotton stalk destruction and regrowth control strategies will be evaluated using remote sensing. Changes in the population dynamics of secondary and emergent pests during active boll weevil eradication will be established. Bioactive or physical agents will be evaluated as alternatives to conventional insecticides for management of secondary and emergent arthropod pests in cotton. The impact of Bt cotton production on the boll weevil eradication activities will be determined in field evaluations of secondary and emergent pest and beneficial insect populations. This is the final report for the project 6204-22000-020-00D, which expires September 30, 2010. The boll weevil pheromone trap is the essential tool used in making malathion treatments for active eradication programs within the U.S. and Mexico. In support of boll weevil eradication, 2 significant amendments to the pheromone lures were evaluated in south Texas as requested by the Texas Boll Weevil Eradication Foundation. The amendments to the lure were the addition of eugenol, and combining dichlorovos, an insecticide used to kill the boll weevil when it enters the trap, with grandlure. Through separate replicated trapping studies, the conclusions were that when eugenol is combined with the grandlure for improved capture of the boll weevils, eugenol does not enhance the capture of boll weevils, nor does it improve the release rate (volatilization) of grandlure over time. The conclusions indicate there is no functional reason for combining eugenol with grandlure, and that it only adds to the cost in manufacturing literally thousands of lures for boll weevil eradication. The additional amendment of combining grandlure with dichlorvos in the same septa indicates that there is no real advantage in using dichlorovs in traps. There was no significant difference in the time required to service the trap, and spiders are the most prevalent arthropod that interfere with trapping efficiency. Adding higher amounts of dichlorvos (over the standard 60 mg) and combining it with the grandlure pheromone also results in reducing weevil attractiveness to the boll weevil trap. Eradication costs could be reduced by not using dichlorvos, handling exposure to trapping personnel would be eliminated, and need for disposal of used kill strips reduced. Agronomic practices and production technologies used in conservation tillage systems have a significant impact on insect pest diversity and density by changing the microclimate in investigated agrobiocenosis (soil temperature and moisture, light interception) and plant canopy structure. Integration of pesticides with conservation tillage, especially in dryland crop production, will provide opportunities for reducing insecticide input by at least 30%. Conservation tillage in dryland cotton production reduced treatments necessary to control boll weevils by approximately two-fold. An improved understanding of the consequences of conservation tillage at the level of insect population dynamics will permit more knowledgeable appraisals of the tradeoffs entailed in adopting this practice. The effects of biotic factors on boll weevil survival, development, and reproduction established by this project have been used by extension entomologists and cotton consultants in: 1) predicting changes in boll weevil populations relative to crop phenology and starting population density; 2) improved methods for predicting cotton fruit loss; and 3) improved economic threshold for the boll weevil. Understanding effects of abiotic factors have led extension entomologists and cotton consultants to: 1) develop more effective sampling protocols; 2) time insecticide applications; and 3) implement IPM strategies targeting susceptible life stages. Accomplishments 01 Promising methods for rearing cotton pest in the laboratory. The green plant bug is a fairly new pest of cotton found only in south Texas. This pest was recently classified by our group as Creontiades signatus. The ability to rear insects in the laboratory is of prime interest to entomologists simply because the species of interest can be studied year round and all stages of development can be further studied at the same time. For the first time, we developed certain laboratory rearing procedures for C. signatus. In particular, this insect can be reared on grocery-bought green bean pods; however, maintaining the quality of the pods during rearing is crucial. Green beans must be changed every other day or the colony will not survive. This information provides entomologists with the ability to maintain colonies of this new pest and furthers studies to determine mechanisms for controlling it in cotton. 02 Mimicking insect damage to cotton bolls can be achieved without the inse It is very important to determine the actual damage that Creontiades signatus can do to cotton bolls. In particular, as the cotton boll ages it hardens, but we do not know when bolls may become safe from the feedi injury caused by this pest. The actual feeding damage of C. signatus can be simulated using a developed injury technique. We used a simulated technique using the injection of pectinase, which mimics the digestive juices secreted by this insect's mouth parts, and is adequate for the continuation of developing economic injury levels for this pest. Furthermore, the use of pectinase allows the researcher the option of no caging the insects on bolls of known age, which greatly facilitates more bolls being examined without the cost of rearing additional insects. 03 Historical database for mitigating the threat of insecticide resistance newer pest in cotton. Because Creontiades signatus is a newer pest of cotton in south Texas, we are developing and establishing a standardized assay to determine the baseline susceptibility of this pest to common insecticides registered for cotton. This pest is a type of plant bug, often called Mirids, that typically shows a strong tendency to develop resistance to certain classes of insecticides. Currently, we have found that C. signatus is very susceptible to registered insecticide used to control them. However, that may certainly change in the future. Having a starting point or baseline on the current susceptibility to these insecticides is important for the detection of insecticide resistance should it occur in the future. If resistance is shown to be occurring, then resistance management strategies as well as other integrated pest management solutions could then be implemented. 04 Effects of feeding overwintering boll weevils with non-cotton host may b an important survival mechanism. Understanding how the boll weevil adul survives during cotton-free period is important to ensure the eradicatio of this insect pest, particularly in subtropical environments where winters are quite mild and boll weevils can remain active year-round. Th utilization of various pollens as a food source by boll weevils may be o of the key survival mechanisms for them in the fall and winter when cott is no longer available. However, it is not fully known if boll weevils c reproduce when feeding strictly on a food source of non-cotton pollen. This information shows that boll weevils are actively feeding during non cotton periods, and leads researchers closer to developing strategies fo controlling them.

Impacts
(N/A)

Publications

Merrill, S., Gebre-Anlak, A., Armstrong, J.S., Peairs, F.B. 2010. Non- linear degree day models for post-diapause development of the sunflower stem weevil (Curculionidae: Coleoptera). Journal of Economic Entomology. 103(2):302-307.
Armstrong, J.S., Coleman, R.J., Duggan, B.L. 2010. Actual and simulated injury of Creontiades signatus Distant (Hemiptera: Miridae) feeding on cotton bolls. Journal of Entomological Science. 45(2):170-177.
Castro, B.A., Armstrong, J.S. 2009. Comparative efficacy of selected insecticide alternatives for boll weevil (Coleoptera: Curculionidae) control using laboratory bioassays. Journal of Cotton Science. 13:189-195.
Greenberg, S.M., Bradford, J.M., Adamczyk Jr, J.J., Smart, J.R., Liu, T. 2010. Insect population trends in different tillage systems of cotton in south Texas. Subtropical Plant Science. 62:1-17.
Lei, Z., Greenberg, S.M., Liu, T. 2009. Feeding, oviposition and survival of Liriomyza trifolii (Diptera: Agromyzidae) on Bt and non-Bt cottons. Bulletin of Entomological Research. 99:253-261.
Greenberg, S.M., Jones, W.A., Liu, T. 2009. Tritrophic interaction among host plants, whiteflies, and parasitoids. Journal of Entomological Science. 34(4):431-445.
Greenberg, S.M., Liu, T., Adamczyk Jr., J.J. 2009. Thrips (Thysanoptera: Thripidae) on cotton in the Lower Rio Grande Valley of Texas: Species composition, seasonal population dynamics, damage and control. Southwestern Entomologist. 34(4):417-430.
Jones, G.D., Greenberg, S.M. 2009. Pollen contamination of boll weevil traps. Grana. 48:297-309.
Jones, G.D., Greenberg, S.M. 2009. Cotton pollen retention in boll weevils, a laboratory experiment. Palynology. 33:157-165.

Progress 10/01/08 to 09/30/09

Outputs
Progress Report Objectives (from AD-416) Characterize aspects of boll weevil biology, ecology, and ethology that affect population dynamics with the aim of enhancing control. Establish properties of grandlure dosage, presentation, formulation, and environmental interaction as they relate to detection of boll weevils. Develop effective alternative strategies and techniques for suppressing and managing boll weevil populations, both on areawide and local scales, including special situations such as environmentally sensitive areas and organic farms. Establish the biology, ecology, behavior, and population dynamics of secondary and emergent arthropod pests, and develop strategies for their effective management. Approach (from AD-416) Patterns of boll weevil dispersal between cotton fields and overwintering habitats will be established using large-capacity traps, and identification of weevils marked with rare earth elements or contaminated with pollen. The boll weevil's utilization of host plants, attractive host plant stages, and nutritional host plant value will be identified using pollen analysis and HPLC analysis of amino acids. Lethal doses and sublethal effects of malathion to boll weevils will be quantified by laboratory bioassays and assessed relative to weevil age, sex, reproductive development, and physiological condition. Temporal patterns and flight response of boll weevils captured in traps baited with standard and "super" formulations of grandlure will be established. Environmental impacts on pheromone release rates and lure longevity will be quantified using meteorological sensors and gas chromatography. Alternative boll weevil control tactics including bioactive and physical agents will be developed for integration into suppression and eradication strategies, including implementation in environmentally sensitive areas and on organic farms. Mechanical and chemical cotton stalk destruction and regrowth control strategies will be evaluated using remote sensing. Changes in the population dynamics of secondary and emergent pests during active boll weevil eradication will be established. Bioactive or physical agents will be evaluated as alternatives to conventional insecticides for management of secondary and emergent arthropod pests in cotton. The impact of Bt cotton production on the boll weevil eradication activities will be determined in field evaluations of secondary and emergent pest and beneficial insect populations. Significant Activities that Support Special Target Populations We determined that alternative foraging resources (pollen plants) play a significant role in adult boll weevil survival during the cotton free period. Additional information on the mortality and reproductive potential after late season population suppression programs could reveal opportunities for improved effectiveness and economics of overwintering boll weevil control. Boll weevil eradication is expected to be the cause of significant changes of population dynamics of secondary pests on cotton and their associated predators and parasites. Integrating cultural practices, using biopesticides and rational insecticides, may provide input strategies that will be more environmentally and economically favorable. We have shown that Bt cotton has the potential to minimize the risk of outbreaks of certain caterpillar pests.

Impacts
(N/A)

Publications

Jones, G.D., Greenberg, S.M., Eischen, F.A. 2007. Almond, pigweed, and melon pollen retention in the boll weevil (Coleoptera: Curculionidae). Palynology. 31:81-93.
James, W.E., Showler, A., Westbrook, J.K., Armstrong, J.S. 2006. Stable isotope tracer marking of individual boll weevils. Journal of Radioanalytical and Nuclear Chemistry. 269:267-270.
Nagoshi, R.N., Armstrong, J.S., Silvie, P., Meagher Jr, R.L. 2008. Structure and distribution of a strain-biased tandem repeat element in fall armyworm (Lepidoptera: Noctuidae) populations in Florida, Texas, and Brazil. Annals of the Entomological Society of America. 101:1112-1120.
Suh, C.P., Armstrong, J.S., Spurgeon, D.W., Duke, S.E. 2009. Comparisons of boll weevil (Coleoptera: Curculionidae) pheromone traps with and without kill strips. Journal of Economic Entomology. 102:183-186.
Greenberg, S.M., Jones, G.D., Adamczyk Jr, J.J., Setamou, M., Liu, T., Armstrong, J.S., Coleman, R.J., Eischen, F.A. 2009. Reproductive potential of field-collected overwintering boll weevils (Coleoptera: Curculionidae) fed on pollen in the laboratory. Insect Science. 16(4):321-327.
Greenberg, S.M., Sappington, T.W., Adamczyk Jr, J.J., Liu, T., Setamou, M. 2008. Effects of photoperiod on boll weevil (Coleoptera: Curculionidae) development, survival, and reproduction. Environmental Entomology. 37(6) :1396-1402.
Greenberg, S.M., Adamczyk Jr, J.J., Sappington, T.W., Jones, W.A., Liu, T. 2008. Interrelationship between plants and insects as the basis for IPM systems. Egyptian Journal of Agricultural Research. 86(1):133-148.
Robinson, A.F., Westphal, A., Overstreet, C., Padgett, G., Greenberg, S.M., Stetina, S.R., Wheeler, T.A. 2008. Detection of suppressiveness against Rotylenchulus reniformis in soil from cotton (Gossypium hirsutum) fields in Texas and Louisiana. Journal of Nematology. 40(1):35-38.
Armstrong, J.S., Coleman, R.J., Setamou, M. 2009. Oviposition patterns of Creontiades signatus (Hemiptera: Miridae) on okra-Leaf and normal-Leaf cotton. Annals of the Entomological Society of America. 102:196-200.
Adamczyk Jr, J.J., Mahaffey, J.S. 2008. Efficacy of Vip3A and Cry1Ab transgenic traits in cotton against various lepidopteran pests. Florida Entomologist. 91(4):570-575.
Siebert, W.M., Babcock, J.M., Nolting, S., Santos, A.C., Adamczyk Jr, J.J., Neese, P.A., King, J.E., Jenkins, J.N., Lorenz, G.M., Fromme, D.D., Lassiter, R.B. 2008. Efficacy of Cry1F insecticidal protein in maize and cotton for control of fall armyworm (Lepidoptera: Noctuidae). Florida Entomologist. 91(4):555-565.
Adamczyk Jr, J.J., Greenberg, S.M., Armstrong, J.S., Mullins, W.J., Braxton, L.B., Lassiter, R.B., Siebert, M.W. 2008. Evaluations of Bollgard, Bollgard II, and Widestrike technologies against beet and fall armyworm larvae (Lepidoptera: Noctuidae). Florida Entomologist. 91(4):531-536.

Progress 10/01/07 to 09/30/08

Outputs
Progress Report Objectives (from AD-416) Characterize aspects of boll weevil biology, ecology, and ethology that affect population dynamics with the aim of enhancing control. Establish properties of grandlure dosage, presentation, formulation, and environmental interaction as they relate to detection of boll weevils. Develop effective alternative strategies and techniques for suppressing and managing boll weevil populations, both on areawide and local scales, including special situations such as environmentally sensitive areas and organic farms. Establish the biology, ecology, behavior, and population dynamics of secondary and emergent arthropod pests, and develop strategies for their effective management. Approach (from AD-416) Patterns of boll weevil dispersal between cotton fields and overwintering habitats will be established using large-capacity traps, and identification of weevils marked with rare earth elements or contaminated with pollen. The boll weevil's utilization of host plants, attractive host plant stages, and nutritional host plant value will be identified using pollen analysis and HPLC analysis of amino acids. Lethal doses and sublethal effects of malathion to boll weevils will be quantified by laboratory bioassays and assessed relative to weevil age, sex, reproductive development, and physiological condition. Temporal patterns and flight response of boll weevils captured in traps baited with standard and "super" formulations of grandlure will be established. Environmental impacts on pheromone release rates and lure longevity will be quantified using meteorological sensors and gas chromatography. Alternative boll weevil control tactics including bioactive and physical agents will be developed for integration into suppression and eradication strategies, including implementation in environmentally sensitive areas and on organic farms. Mechanical and chemical cotton stalk destruction and regrowth control strategies will be evaluated using remote sensing. Changes in the population dynamics of secondary and emergent pests during active boll weevil eradication will be established. Bioactive or physical agents will be evaluated as alternatives to conventional insecticides for management of secondary and emergent arthropod pests in cotton. The impact of Bt cotton production on the boll weevil eradication activities will be determined in field evaluations of secondary and emergent pest and beneficial insect populations. Significant Activities that Support Special Target Populations The green mirid has continued to cause concern in cotton production of south Texas with populations currently being treated with insecticides between the Corpus Christi and Houston areas. Understanding the damaged caused and how that relates to yield is being investigated by field-crop entomologists with the USDA-ARS, Weslaco. We have made significant progress in developing a bioassay method methodology for determining the susceptibility of the green mirid exposed to insecticides that work by contact and ingestion. In addition, we continue to characterize aspects of boll weevil biology and ecology that affect population dynamics that are relevant to enhancing the efficacy of management strategies or tactics. We determined that alternative foraging resources (pollen plants) play a significant role in adult boll weevil survival during the cotton free period. Additional information on the mortality and reproductive potential after late season population suppression programs could reveal opportunities for improved effectiveness and economics of overwintering boll weevil control. The boll weevil eradication is expected to be the cause of significant changes in population dynamics of secondary pests in cotton, and their associated predators and parasites. Integration of cultural practices, using biopesticides and judicious use of insecticides, may provide control strategies that will be more environmentally and economically favorable. Furthermore, Bt cotton has proven itself to be a useful tool in eradication of the boll weevil in minimizing risk of outbreaks of lepidopteran pests. We determined that not all transgenic Bt cotton provide the same level of control against certain lepidopteran pests. (NP 304, Component 3)

Impacts
(N/A)

Publications

Greenberg, S.M., Jones, G.D., Eischen, F.A., Coleman, R.J., Adamczyk Jr, J. J., Liu, T., Setamou, M. 2007. Survival of boll weevil (Coleoptera: Curculionidae) adults after feeding on pollens from various sources. Insect Science. 14:503-510.
Nagoshi, R.N., Meagher Jr, R.L., Flanders, K., Gore, J., Jackson, R.E., Lopez, J., Armstrong, J.S., Buntin, G.D., Sansone, C., Leonard, B.R. 2008. Using haplotypes to monitor the migration of fall armyworm (Lepidoptera: Noctuidae) corn-strain populations from Texas and Florida. Journal of Economic Entomology. 101(3):742-749.
Coleman, R.J., Hereward, H.P., De Barro, P.J., Frohlich, D.R., Adamczyk Jr, J.J., Goolsby, J. 2008. Molecular comparison of Creontiades plant bugs from South Texas and Australia. Southwestern Entomologist. 33(2):111-117.
Jackson, R.E., Bradley, J., Van Duyn, J., Leonard, B.R., Allen, C., Luttrell, R., Adamczyk Jr, J.J., Gore, J., Hardee, D.D., Voth, R., Sivasupramaniam, S., Mullins, W., Head, G. 2008. Regional Assessment of Helicoverpa zea (Lepidoptera: Noctuidae) Populations on Cotton and Non- Cotton Crop Hosts. Entomologia Experimentalis et Applicata. 126:89-106
Greenberg, S.M., Jones, W.A., Liu, T. 2008. Bemisia tabaci (Homoptera: Aleyrodidae) instar effects on rate of parasitism by Eretmocerus mundus and Encarsia pergandiella (Hymenoptera: Aphelinidae). Entomological Science. 11:97-103.
Li, Y., Greenberg, S.M., Liu, T. 2007. Orientation behavior, development and survival of Trichoplusia ni (Lepidoptera: Noctuidae) larvae on cotton expressing Cry1Ac and Cry2Ab and conventional cotton. Journal of Insect Behavior. 20(5):473-488.
Armstrong, J.S., Richman, D. 2007. Interference of boll weevil trapping by spiders (Araneida) and an evaluation of trap modification to reduce unwanted arthropods. J. Entomol. Sci. 42(3):392-398.

Progress 10/01/06 to 09/30/07

Outputs
Progress Report Objectives (from AD-416) Characterize aspects of boll weevil biology, ecology, and ethology that affect population dynamics with the aim of enhancing control. Establish properties of grandlure dosage, presentation, formulation, and environmental interaction as they relate to detection of boll weevils. Develop effective alternative strategies and techniques for suppressing and managing boll weevil populations, both on areawide and local scales, including special situations such as environmentally sensitive areas and organic farms. Establish the biology, ecology, behavior, and population dynamics of secondary and emergent arthropod pests, and develop strategies for their effective management. Approach (from AD-416) Patterns of boll weevil dispersal between cotton fields and overwintering habitats will be established using large-capacity traps, and identification of weevils marked with rare earth elements or contaminated with pollen. The boll weevil's utilization of host plants, attractive host plant stages, and nutritional host plant value will be identified using pollen analysis and HPLC analysis of amino acids. Lethal doses and sublethal effects of malathion to boll weevils will be quantified by laboratory bioassays and assessed relative to weevil age, sex, reproductive development, and physiological condition. Temporal patterns and flight response of boll weevils captured in traps baited with standard and "super" formulations of grandlure will be established. Environmental impacts on pheromone release rates and lure longevity will be quantified using meteorological sensors and gas chromatography. Alternative boll weevil control tactics including bioactive and physical agents will be developed for integration into suppression and eradication strategies, including implementation in environmentally sensitive areas and on organic farms. Mechanical and chemical cotton stalk destruction and regrowth control strategies will be evaluated using remote sensing. Changes in the population dynamics of secondary and emergent pests during active boll weevil eradication will be established. Bioactive or physical agents will be evaluated as alternatives to conventional insecticides for management of secondary and emergent arthropod pests in cotton. The impact of Bt cotton production on the boll weevil eradication activities will be determined in field evaluations of secondary and emergent pest and beneficial insect populations. Significant Activities that Support Special Target Populations Evaluate Bt-Cotton Technology for Lepidopteran Pests in cotton in the LRGV of Texas during Boll Weevil Eradication: The major noctuid pests in the LRGV cotton are bollworms, beet armyworms, cabbage loopers, tobacco budworms, and fall armyworms. However, the pest status of beet armyworms and cabbage loopers may soon change due to the initiation of the Boll Weevil Eradication Program (BWEP). Growers are aware of the increased risk of secondary pest outbreaks during the BWEP, and Bt cotton is known to reduce the impact of caterpillars as pests. Our preliminary results demonstrated that under high populations of caterpillars, Bt cottons, which contain 2 Bt proteins, significantly reduced cotton leaf and fruit damage, resulting in greater yields. Increased acreage planted with Bt cottons could be a vital tool in the Lower Rio Grande Valley, especially under BWEP, providing a management option that has positive environmental, social, and economic outcomes. Season long evaluations were conducted using a leaf-dish assay for evaluating the effectiveness of Bt cottons on a secondary pest, the fall armyworm. The methodology for lyophilizing cotton tissue and incorporating into meridic diet was established for determining the sublethal effects of Bt proteins on the survivorship and development of larvae. Field experiments were conducted to determine the pest status of the beet armyworm on cottons containing various Bt proteins. This pest is truly secondary, reaching outbreak status when beneficial insects are disrupted by insecticides. Our data indicates that this pest can survive to cause damage to plants containing all commercially available Bt proteins. Furthermore, we determined that some Bt proteins are more efficacious than others and are expressed differently in the plant relative to one another. These findings will be critical for controlling this pest in an outbreak, as well as for managing resistance to various Bt proteins. Accomplishments Evaluate Bt-Cotton Technology for Lepidopteran Pests in cotton in the Lower Rio Grande Valley of Texas during Boll Weevil Eradication: Knowledge of the effects of Bt cotton on pest management will enhance the long- term success of the boll weevil eradication program. Bt cotton has proven itself useful by minimizing the risk of outbreaks of secondary caterpillar pests. Dual-gene products (Bollgard II� and WideStrikeTM), compared with Bollgard� and conventional cotton, significantly reduced cotton leaf and fruit damage, and live larvae of beet armyworms, cabbage loopers, and black cutworms, throughout the growing season. Increased acreage planted with dual-gene cottons could be a vital tool in the Lower Rio Grande Valley of Texas, providing a management option that has positive environmental, social, and economic outcomes. These research results were presented to farmers, extension personnel, and industry representatives. (NP 304, Crop Protection and Quarantine, Component II, Biology of Pests and Natural Enemies) Evaluate stalk destruction strategies to minimize boll weevil population: During the mild-winters found in the subtropical Lower Rio Grande Valley of Texas, cotton plants can re-grow to produce fruit. These fruiting structures can sustain year-round boll weevil populations. The success of the Boll Weevil Eradication Program (BWEP) will be dependent on thorough stalk destruction following harvest. The herbicide 2,4-D amine applied twice (immediately and 14 days after cotton was harvested) at 1 pound of formulated product in 10.0 gallons of water per acre was 100% effective in killing stalks, regardless of whether they were shredded or standing, or whether harvest was by stripper or picker. These findings showed that 2,4-D Amine cotton stalk destruction eliminated food and reproductive opportunities, and thus aided in managing overwintering boll weevils. This research finding was included in IPM cotton production for Texas agricultural extension service. (NP 304, Crop Protection and Quarantine, Component II, Biology of Pests and Natural Enemies) Significant Activities that Support Special Target Populations ARS-Weslaco worked collaboratively with Dr. Boris Castro, Extension/Research Entomologist with Texas A&M to determine the susceptibility of boll weevils to several different insecticides in the event that malathion is taken off the market, or for some reason no longer available. The Technical Advisory Committee for Texas Boll Weevil Eradication requested that this work be conducted. In addition, a grant for $10,000 was funded by Cotton Incorporated to conduct this work. Several different insecticides have been screened using a leaf bioassay and a direct application method. The methodology for both types of experiments were developed. Technology Transfer Number of Non-Peer Reviewed Presentations and Proceedings: 10

Impacts
(N/A)

Publications

Greenberg, S.M., Armstrong, J.S., Setamou, M., Sappington, T.W., Coleman, R.J., Liu, T. 2006. Circadian rhythms of feeding, oviposition, and emergence of the boll weevil (Coleoptera: Curculionidae). Journal of Insect Science. 13(6):461-467.
Greenberg, S.M., Sappington, T.W., Setamou, M., Armstrong, J.S., Coleman, R.J., Liu, T.X. 2007. Reproductive potential of overwintering, F1, and F2 female boll weevils (Coleoptera: Curculionidae) in the Lower Rio Grande Valley of Texas. Environmental Entomology. 36(2):256-262.
Li, Y.X., Greenberg, S.M., Liu, T.X. 2007. Effect of Bt cotton expressing Cry1Ac and Cry2Ab, non-Bt cotton and starvation on survival and development of Trichoplusia ni (Lepidoptera: Noctuidae). Pest Management Science. 63:476-482.
Adamczyk Jr., J.J., Meredith, W.R. 2006. Selecting for efficacy of Bollgard cotton cultivars against various lepidoptera using forward breeding techniques. Journal of Economic Entomology. 99(5):1835-1841.
Showler, A.T., Armstrong, J.S. 2007. Kaolin particle film associated with increased cotton aphid (Homoptera: Aphididae) infestations in cotton. Entomologia Experimentalis et Applicata. 124:55-60.

Progress 10/01/05 to 09/30/06

Outputs
Progress Report 1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? Although the boll weevil has been eradicated from most areas east of the Mississippi River, it still infests as much as 40% of the total cotton acreage in the U.S. In spite of control efforts costing as much as $50 million a year, cotton yields in a recent year of heavy infestation were reduced by almost 600,000 bales by the boll weevil, amounting to production losses of more than $200 million. Because of secondary pest problems and high costs, eradication programs have come under increasing scrutiny for their heavy reliance on conventional pesticides; however, effective boll weevil management by producers outside of such programs is costly and difficult. This project develops management techniques and strategies for controlling the boll weevil that will reduce pesticide input and increase net profitability for the cotton producer. Focus of the project is on improved efficacy and predictive capability of boll weevil trapping systems, alternative management strategies such as preemptive insecticide treatments of early season cotton to reduce the need for later chemical intervention, new and alternative cultural practices for manipulating field conditions to minimize pest problems, and use of biorational substances as alternatives to conventional insecticides in providing effective boll weevil control. Work is also focused on developing boll weevil management techniques or control technology that do not precipitate secondary outbreaks of beet armyworms and other pest insects. Lepidopteran pests of cotton continue to pose a threat to cotton production throughout the cotton belt, especially during and after the implementation of the boll weevil eradication program. The beet armyworm, in particular, was responsible for numerous crop losses in the 1990's and was often, but not entirely, associated with the boll weevil eradication program or other early season pesticide use. These outbreaks were typically attributed to decimation of natural enemy populations by pesticide applications. Understanding the complex interaction between transgenic Bt cotton technology and bollweevil eradication is still greatly needed. Development of strategies for mitigating outbreaks of lepidopteran pests is further needed. This is particularly true for the Lower Rio Grande Valley (LRGV) of Texas where the boll weevil eradication program has now just been implemented and the use of Bt cotton continues to increase rapidly. In addition, lepidopterans are a continuing concern in the conventional cotton refuges mandated by EPA where Bt cotton is grown. This project contributes to the Crop Protection and Quarantine National Program (NP 304), and specifically addresses the Biology of Pests and Natural Enemies; Plant, Pest, and Natural Enemy Interactions and Ecology; Pest Control Technologies; and Integrated Pest Management Systems and Areawide Suppression Programs components of NP 304 by developing new technology and management systems for more effective and environmentally friendly control of the boll weevil. The project, either directly or indirectly, benefits all components of the U.S. cotton production and processing industries. The U.S. consumer benefits as the result of stability in cotton supplies and prices. 2. List by year the currently approved milestones (indicators of research progress) Year 1 (FY 2006) 1. Establish feeding and oviposition of overwintering boll weevil. 2. Complete dispersal and habitat field studies. 3. Complete lab assays on boll weevil longevity and fecundity after feeding on different parts of cotton fruiting bodies. 4. Develop methodology for sublethal effects of malathion on reproduction. 5. Complete field experiment and pheromone volatile analysis. 6. Complete field experiment on proaction and hull split. 7. Complete lab assays for guayule resin. Year 2 (FY 2007) 1. Establish effects of temperature and photoperiod on boll weevil development and reproductive potential. 2. Evaluate statistical models for mortality and lethal dose. 3. Develop gas chromatograph analysis of grandlure and eugenol and establish standard curves for detection. 4. Field test eugenol formulations combined with grandlure for release and residual of pheromone. 5. Develop Cooperative Agreement with Hercon. 6. Finish data analysis on proaction and hull split experiment. 7. Evaluate large field performance of (1) preharvest applications of insecticides and conventional cotton defoliants; (2) chemical cotton stalk destruction, and (3) quality of defoliation and regrowth control using remote sensing. 8. Evaluate Bt-cotton technology for Lepidopteran pests in cotton. Year 3 (FY 2008) 1. Establish circadian rhythms of boll weevil oviposition and emergence. 2. Complete cesium dosage assays. 3. Complete nutritional/chemical analyses of different parts of cotton fruiting bodies. 4. Develop lipid content process to determine fat body content and susceptibility to malathion. 5. Complete field testing of eugenol dosages combined with grandlure. 6. Complete field testing of standard and extended formulations of grandlure for release and residual of pheromones. 7. Complete assays on citrus extract. 8. Establish effects of different tillage systems on population dynamics of boll weevil and secondary pests in irrigated cotton. 9. Complete lab assays on sesame and secondary pests. 10. Determine the efficacy of Bt-cotton of differing maturity and Lepidopteran pests in different instars, and evaluate effects of Bt- cultivars on larval mortality. Year 4 (FY 2009) 1. Identify pollen spectra as foraging resources of overwintering boll weevil. 2. Complete cesium delivery through host plants. 3. Determine susceptibility to malathion of boll weevils in diapause versus weevils actively feeding and reproductive. 4. Evaluate trap modifications and combinations of grandlure and insecticide for improved trapping efficiency. 5. Complete field experiments on kaolin. 6. Establish effects of biopesticides and other organic products as defoliants in organic cotton using remote sensing. 7. Establish management of secondary pests with biopesticides and organic products. 8. Estimate effects of Bt-cotton on non-target pests and beneficial insects. Year 5 (FY 2010) 1. Finish neutron activation of samples. Milestone deleted due to re- direction of scientist. 2. Establish effects of feeding overwintering boll weevil various pollen on their survival, development and reproduction. 3. Finish lab assays on nutritional value of vegetative foods to boll weevil. Milestone deleted due to re-direction of scientist. 4. Summarize boll weevil mortality probablities for specific age, sex, reproductive condition and physiological state. 5. Complete lab assays for other bioactive compounds. Milestone deleted due to re-direction of scientist. 6. Evaluation efficacy of biopesticides and organic products on boll weevil survival, development, and reproduction. 7. Establish effects of mechanical and chemical (biopesticides and other organic products) tactics on cotton stalk destruction in organic cotton using remote sensing. 8. Estimate population dynamics of secondary pests in cotton and their associated predators and parasites during and after boll weevil eradication. 9. Develop a system for insect and disease control in organic cotton. 4a List the single most significant research accomplishment during FY 2006. Chemical destruction of cotton stalks in the Lower Rio Grande Valley (LRGV) of Texas for overwintering boll weevil control. In the LRGV of Texas, cotton regrowth and produce fruit from undestroyed stalks through the winter, and in spring weevils from such locations become a serious threat. The success of the Boll Weevil Eradication Program, which was reintroduced in the LRGV in 2005, will be dependent on thorough stalk destruction following harvest. However, adverse weather conditions and conservation tillage often impede immediate and complete stalk destruction using typical tool implements, and alternative stalk control methods are needed. Our studies provide an examination of efficacy of different herbicides, rates, spray volumes, and application timings on shredded or standing cotton stalks after stripper or picker harvest. The herbicide 2,4-D Amine applied twice (immediately and 14 days after cotton was harvested) at one pound of formulated product in 10.0 gallons of water per acre was 100% effective in killing stalks, regardless of whether they were shredded or standing, or whether harvest was by stripper or picker. These findings showed that 2,4-D Amine cotton stalk destruction eliminated food and reproductive opportunities for managing overwintering boll weevils. This project directly supports ARS National Program 304, Crop Protection and Quarantine. The evaulation of the extended or "superlure" had much interest from industry (i.e., pheromone manufacturing companies) and Boll weevil eradication personnel. The interest was evident in the number of phone calls received and requests for result of the data. Several key Boll weevil eradication personnel from the Southeast BWE, Louisiana BWE, and Texas BWE requested this information and the results were presented at a national meeting and published in a Beltwide and peer reviewed journal. 4c List significant activities that support special target populations. The Texas boll weevil eradication Field Director asked us to determine the susceptibility of boll weevils in the Uvalde area to malathion. This was done in conjunction with Dr. Patricia Patrientanio, insect toxicologist from Texas A&M. Dr Petrientanio used the vial assay while we employed the direct topical application method. The results of the two different assays showed similar results in that the boll weevils collected from Uvalde were several times (10-13x) harder to kill. The special target population supported is the Texas Boll Weevil Eradication Program. 5. Describe the major accomplishments to date and their predicted or actual impact. Effects of different tillage systems on population dynamics of boll weevil in dryland cotton. We studied the effects of conservation and conventional tillage systems in dryland cotton on soil surface temperature, soil moisture, plant canopy structure, light interception, timing of fruit set, and how these factors affect boll weevil populations throughout the growing season. Dryland cotton plants in conventional tillage systems allocated more resources into vegetative growth because of the lack of soil moisture, while a conservation tillage system promoted fruiting at a higher rate. Plants grown in a conventional tillage system significantly increased light interception and shading of the soil surface, and significantly decreased soil surface temperature between the rows than plants grown in a conservation tillage system. High temperature in conservation tillage fields significantly increased boll weevil mortality in infested squares shed from plants. Also high surface soil temperature was the major factor responsible for the mortality of boll weevils in fallen fruit in post-harvest conservation tillage fields in the Lower Rio Grande Valley. When the infested fruit were buried in conventional tillage fields, boll weevil mortality was reduced by protection of the larvae from lethally hot temperatures by the 25-cm layer of soil. Burial of infested fruit resulted in a significantly greater weevil mortality in wet sand or clay than in dry or clumpy soil conditions. These studies showed that among important alternatives to insecticides are cultural control techniques. Conservation tillage in dryland cotton production contributes to lower boll weevil numbers by adversely affecting the life cycle of the insect through habitat modification and will reduce the number of treatments necessary to control boll weevils which would constitute a great savings to the farmers. Results from this research showed additional benefits of conservation tillage, other than wind erosion control and water conservation. An improved understanding of the consequences of conservation tillage at the level of insect population dynamics will permit more knowledgeable appraisals of the tradeoffs entailed in adopting this practice. Studies showed also the feasibility of cultural management of overwintered boll weevils. This research applies to NP 304, Protection and Quarantine. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Greenberg, S.M. 2005. Evaluating Effectiveness of Some Agricultural Operations on Cotton by Using Remote Sensing Technology. 20th Workshop of Remote Sensing Technology, Otober 15, 2005, Weslaco, Texas. Greenberg, S.M. 2005. Chemical Destruction of Cotton Stalks in the Lower Rio Grande Valley of Texas for Overwintering Boll Weevil Control. Entomological Science Day, October 26-28, 2005, College Station, Texas. Greenberg, S.M. 2005. Circadian Rhythms of Oviposition and Emergence of the Boll Weevil. 53rd Annual Meeting of the ESA, December 15-18, 2005, Fort Lauderdale, Florida. Greenberg, S.M. 2005. Food Choice, Food Consumption, Survival and Development of Cabbage Looper Larvae Exposed to Bollgard II and Conventional Cotton Leaves. 53rd Annual Meeting of the ESA, December 15- 18, 2005, Fort Lauderdale, Florida. Greenberg, S.M. 2006. Comparative Efficacy of Bt and non-Bt Cottons on the Bollworm-Tobacco Budworm Complex, Cabbage Looper, and Beet Armyworm in the Lower Rio Grande Valley of Texas. 2006 Beltwide Cotton Conference, January 3-6, 2006, San Antonio, Texas. Greenberg, S.M. 2006. Temperature Effects of Boll Weevil (Coleoptera: Curculionidae) Development Survival, and Reproduction. 54th Annual Meeting of the Southwestern Branch of the ESA and Society of Southwestern Entomologists, February 27-March 2, 2006, Austin, Texas. Greenberg, S.M. 2006. Food Choice and Survival of Different Instars Trichoplusia ni Exposed to Bollgard II and Conventional Cotton Leaves. 54th Annual Meeting of the Southwestern Branch of the ESA and Society of Southwestern Entomologists, February 27-March 2, 2006, Austin, Texas. Moran, P. J., Greenberg, S.M. 2006. Winter cover crops and vinegar as weed control techniques in sustainable cotton production. In: Proceedings of the Beltwide Cotton Conferences, January 3-6, 2006, San Antonio, Texas. 2006 CDROM. p. 2188-2195.

Impacts
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Publications

Greenberg, S.M., Armstrong, J.S., Coleman, R.J., Bradford, J.M., Liu, T., Adamczyk Jr., J.J. 2006. Comparative efficacy of Bollgard II and non-bt cotton on the Noctuid Complex in the Lower Rio Grande Valley of Texas. In: Proceedings of the Beltwide Cotton Conferences, January 3-6, 2006, San Antonio, Texas. 2006 CDROM.
Armstrong, J.S., Spurgeon, D.W., Suh, C.P. 2006. Comparisons of standard and extended-life boll weevil pheromone lures. Journal of Economic Entomology. 99:323-330.
Armstrong, J.S., Richman, D.B. 2006. Identifying the predators that interfere with boll weevil trapping and evaluating lure/insecticide combinations. In: Proceedings of the Beltwide Cotton Conferences, January 3-6, 2006, San Antonio, Texas. 2006 CDROM.
Lehman, R.M., Osborne, S.L., Rosentrater, K.A. 2005. Field decomposition of genetically-modified corn residue. ASA-CSSA-SSSA International Annual Meetings in Salt Lake City, Utah, November 6-10, 2005.
Showler, A., James, W.D., Armstrong, J.S., Westbrook, J.K. 2006. An experiment using neutron activation analysis and a rare earth element to mark cotton plants and two insects that feed on them. Applied Radiation and Isotopes. 64:875-880.
Li, Y.X., Greenberg, S.M., Liu, T.X. 2006. Effects of Bt cotton expressing Cry1ac and Cry2ab and non-Bt cotton on behavior, survival and development of Trichoplusia ni (Lepidoptera: Noctuidae). Crop Protection Journal. 25:940-948.
Armstrong, J.S., Setamou, M., Showler, A., Greenberg, S.M. 2006. Sublethal effects of malathion on boll weevil (Coleoptera: Curculionidae) fecundity when maintained on cotton squares and artificial diet. Insect Science and Its Application. 13:287-292.
Greenberg, S.M., Setamou, M., Sappington, T.W., Coleman, R.J., Armstrong, J.S., Liu, T. 2005. Temperature-dependent development and reproduction of the boll weevil (Coleoptera: Curculionidae). Journal of Insect Science. 12:231-240.
Yang, C., Greenberg, S.M., Everitt, J.H., Norman, J.W. 2006. Assessing cotton stalk destruction with herbicides using remote sensing technology. Journal of Cotton Science. 10(2):136-145.