2009 Annual Report
1a.Objectives (from AD-416)
Develop and refine boll weevil monitoring tactics to enhance suppression or eradication efforts. Develop improved and novel methods for elucidating the biology and ecology of southern green stink bugs. Improve current management strategies for cotton fleahopper through development of ecologically interpretable monitoring methods, elucidation of dispersal strategies in relation to the environment, and improved understanding of cotton fleahopper/cotton plant interactions. Identify and characterize neuropeptide hormones of arthropod pests and develop biostable, bioavailable mimics that can disrupt critical life processes to provide effective and environmentally sensitive pest control.
1b.Approach (from AD-416)
Studies will be conducted to investigate effects of diet on pheromone production by boll weevils, effects of the trap environment on boll weevil colonization patterns and captures in traps, and methods to locate and manage sources of weevil re-infestations. New methods will be developed to determine the reproductive/physiological development of southern green stink bugs and their utilization of wild host plants and crops. Dissections to identify reproductive/physiological characteristics and neuropeptide chemistry/biostable mimic technology will combine to reveal basic southern green stink bug biology and mechanisms for their behavior and ecology. This information will help determine the timing and approaches to manage southern green stink bug populations. Various pest sampling technologies and techniques will be evaluated relative to a reference sampling method in cotton to determine an efficient and effective sampling technology. Cotton fleahopper dispersal from uncultivated plants and colonization of early-season cotton fields will be determined relative to weather and physiological characteristics of the host plants. Plant stage-dependent feeding and oviposition activity, and consequent instar- or stage-dependent plant injury will be defined. Completion of the research will result in new sampling technologies and cotton fleahopper management guidelines. Knowledge of the role of neuropeptides will be developed which will lead to the development of neuropeptide mimics that resist degradation by enzymes in the digestive tract, hemolymph, and tissues. Research will be conducted to identify neuropeptides, and to develop and evaluate neuropeptide mimics that can regulate diuresis, ecdysis, diapause, and reproduction as tools to study the biology of sucking bugs and as pest insect management agents.
Work under this project during FY 2009 resulted in significant progress in identifying diverse plant habitats of cotton insect pests, and exploiting this information to define ecological processes, including dispersal. Significant progress was made in identification of insecticides that are effective against the cotton fleahopper, but not detrimental to populations of beneficial insects. Longevity and survival of cotton fleahopper adults on various diets were examined to identify an adequate diet(s) for maintaining laboratory colonies of fleahoppers. Analyses of three independent sets of data (weather conditions, pheromone lure release rates, and pheromone composition of field- and trap-collected boll weevils) were interpreted to identify factors that may be contributing to the poor performance of pheromone traps in portions of the South Texas/Winter Garden zone of Texas. A hand-held device, similar to the "electronic nose" used by the military to detect explosives, was tested for detection of boll weevil pheromone. This device may provide a low-cost, highly portable, and effective method for detecting the presence of boll weevils in cotton fields. Spectral signatures of cotton plants and other row crops were obtained with ground- and air-based sensors. This information brings us one step closer to developing a remote-sensing system for detecting regrowth and volunteer cotton plants. Food diets were correlated with reproduction in southern green stink bugs and characterized by reproductive morphology of the bugs. Progress has been made in quantifying the relative dimensions and suppleness of several taxa of pollen grains, and preliminary results suggest that pollen grains that have a smooth outside layer (exine) are more pliable that those with an ornate exine. This information is important because pollen grains found inside pest insects can be used to identify the dispersal of these insects from their previous habitats.
Blocking pheromone production in moths: The immature stages of many species of insects in the Order Lepidoptera (which includes moths) are destructive crop pests, and new technology is needed to successfully manage these insects in U.S. crop production. Male and female lepidopteran insects recognize and are attracted to each other for reproductive purposes through release/reception of trace levels of very highly volatile chemicals called pheromones. Disruption of pheromone signaling between the sexes offers a promising approach to control; it is well known that pheromone synthesis and recognition in insects are controlled by internal hormones known as neuropeptides. In collaboration with scientists in Israel, we chemically synthesized neuropeptide "mimics" that effectively blocked pheromone production in the species of pest moth studied. Importantly, the synthetic version of the neuropeptide, when applied to the outside of the living insect, effectively penetrated to the internal organs where it exhibited its pheromone-inhibiting effects. This accomplishment is important because it brings us one step closer to the development of practical neuropeptide-like substances that will disrupt normal reproduction and thus provide effective control of lepidopteran pest insects in an environmentally friendly fashion.
Highly active neuropeptide mimics in mosquitoes and ticks: Neuropeptides are short chains of amino acids that regulate critical life functions in insects and other arthropods including ticks. Manipulation of neuropeptide action offers promise as new pest arthropod control technology; however, more biostable versions of neuropeptides that can resist degradation by enzymes in pest arthropods will be required in order for neuropeptide technology to be developed for effective pest control. In collaboration with scientists at Texas A&M University and at the University of London, we have for the first time created new chemical versions of an arthropod neuropeptide that is even more active than the natural neuropeptide in increasing water loss in the mosquito (Aedes aegypti) and tick (Boophilus microplus). This work is important because it brings us closer to the development of practical neuropeptide-like substances that will dessicate pest arthropods and provide effective control in an environmentally sensitive fashion.
Diet affects boll weevil pheromone production: Improved knowledge of boll weevil chemical ecology is critical for improving pheromone trapping methods that are key monitoring tools in ongoing efforts to eradicate the weevil from the U.S. The boll weevil pheromone is a mixture of highly volatile chemicals that are released by the weevils in trace amounts and allow male and female weevils to recognize and be attracted to each other for reproduction. We established that the nature of the diet consumed by adult boll weevils greatly affects the timing of pheromone release by the weevils, indicating that dietary factors have significant implications for efficiency in boll weevil reproduction. This knowledge will lead to improved interpretation of weevil pheromone trap captures relative to seasonal changes in natural pheromone production by weevils in nearby cotton fields.
Improved sampling of cotton fleahoppers: The cotton fleahopper is an important pest insect in cotton. The standard technique for assessing fleahopper abundance in cotton involves direct counts of adults and immature stages (nymphs) on cotton plants. However, many producers do not sample for fleahoppers because this procedure is laborious and time-consuming. In collaboration with Texas AgriLife scientists in Corpus Christi, Texas, we conducted extensive studies on the distribution of fleahopper adults and nymphs on cotton plants, at different times of the day, to establish if there was a time when fleahoppers could be easily collected from only the upper growth tips (terminals) of the plant. The work showed clearly that most fleahoppers stay on the cotton terminals, regardless of time of day. This finding is very important because sampling cotton terminals can be easily and quickly accomplished, it gives good information on the numbers of fleahoppers present, and the method will encourage producers and crop consultants to more effectively monitor their crops for this insect so that more intelligent fleahopper management decisions can be made.
Reproductive development of the southern green stink bug: The southern green stink bug (SGSB) and related species have reached elevated pest status in the U.S. following success of boll weevil eradication efforts. Accurate assessments of reproductive development and potential of the SGSB are required to understand the biology and ecology of the insect, and to make appropriate decisions concerning effective control of this pest. We developed a definitive system for accurately rating and assessing the different reproductive stages of the SGSB. This accomplishment provides sound information, including quality photographic references, that will greatly facilitate work by researchers who are seeking to develop a better understanding of this insect's biology, physiology, and reproductive parameters. Better decisions related to effective management of this important crop pest will result.
Non-cotton hosts of the cotton fleahopper: The cotton fleahopper is an early-season pest of cotton that can drastically reduce fruit set, thereby reducing yield. Fleahopper infestations typically originate from uncultivated plant hosts in or near cotton fields; increased knowledge of the non-cotton host plants utilized by fleahoppers is required to better understand the dynamics of this insect's survival, reproduction, and sources of cotton field infestations. We identified numerous seasonal hosts utilized by the cotton fleahopper, and developed a comprehensive and user-friendly compendium of non-cotton hosts throughout the U.S. Cotton Belt. This work, and particularly the plant host compendium, provides cotton researchers in the U.S. with a valuable resource for identifying host plants and assessing the significance of their contribution to fleahopper infestations in cotton.
Pollen longevity in the boll weevil gut: Dispersal of boll weevils in and around cotton fields hinders pest management because the weevils may not be in the cotton field when pesticides are applied. Monitoring pollen grains from various plants that are found on and in boll weevils can be important in defining the movement of weevils into and out of fields. In collaboration with ARS scientists at Weslaco, Texas, we measured pollen retention in the boll weevil gut. Complete pollen grains of cotton were found in the weevil gut as long as 24 hours after the insects had fed on the plant. This work is important because it shows that monitoring pollen grains in the boll weevil digestive tract can give solid evidence of the time line of weevil feeding and definitive evidence of the specific plants being fed upon. Increased knowledge on boll weevil dispersal between cotton and native plants will lead to more timely and effective insecticide applications and will significantly support ongoing efforts to eradicate the weevil from the U.S.
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Paluzzi, J., Russell, W.K., Nachman, R.J., Orchard, I. 2008. Isolation, cloning and expression mapping of a gene encoding an anti-diuretic hormone and other CAPA-related peptides in the disease vector, Rhodnius prolixus. Endocrinology. 149:4638-4646.
Esquivel, J.F. 2007. Evaluation of puncture types as indicators of boll weevil (Coleoptera: Curculionidae) oviposition in cotton squares. Environmental Entomology. 36:183-187.
Mertens, I., Clinckspoor, I., Janssen, T., Nachman, R.J., Schoofs, L. 2005. Fmrfamide related peptide ligands activate the Caenorhabditis elegans orphan GPCR Y59H11AL.1. Peptides. 27:1291-1296.
Bryant, V.M., Jones, G.D. 2006. Forensic palynology: Current status of a rarely used technique in the United States of America. Forensic Science. 163:183-197.
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.
Jones, G.D., Bryant, V.M. 2004. The use of ETOH for the dilution of honey. Grana. 43:174-182.
Nachman, R.J., Coast, G.M., Fehrentz, J., Kaczmarek, K., Zabrocki, J., Pryor, N.W., Martinez, J. 2003. A C-terminal insect kinin analog enhances inhibition of weight gain and induces significant mortality in Helicoverpa zea. Peptides. 24:1615-1621.
Nachman, R.J. 2006. Invertebrate neuropeptides VI. Peptides. 27:482.
Nachman, R.J., Zubrzak, P., Williams, H., Strey, A.A., Zdarek, J. 2007. A beta-amino acid pyrokinin analog induces irregular pupariation behavior in larvae of the flesh fly Sarcophaga bullata. Pestycydy/Pesticides. 210:3979-3989.
Nachman, R.J., Pietrantonio, P., Coast, G.M. 2009. Towards the development of novel pest management agents based upon insect kinin neuropeptide analogs. Annals of the New York Academy of Sciences. 1163:251-261.
Nachman, R.J., Teal, P.E., Ben-Aziz, O., Davidovitch, M., Zubrzak, P., Alstein, M. 2009. An amphiphilic, PK-PBAN analog is a selective pheromonotropic antagonist that penetrates the cuticle of a heliothine insect. Peptides. 30:616-621.
Nachman, R.J., Ben-Aziz, O., Davidovitch, M., Zubrzak, P., Isaac, R.E., Strey, A.A., Reyes-Rangel, G., Juaristi, E., Williams, H.J., Alstein, M. 2009. Biostable beta-amino acid PK/PBAN analogs: Agonist and antagonist properties. Peptides. 30:608-615.
Nachman, R.J., Kim, Y., Wang, X.J., Etzkorn, F.A., Kaczmarek, K., Zabrocki, J., Adams, M.E. 2009. Potent activity of a PK/PBAN analog with an (E)-alkene, trans-Pro mimic identifies the Pro orientation and core conformation during interaction with HevPBANR-C receptor. Bioorganic and Medicinal Chemistry. 17:4216-4220.
Nachman, R.J., Wang, X.J., Etzkorn, F.A., Ben-Aziz, O., Davidovitch, M., Kaczmarek, K., Zabrocki, J., Strey, A.A., Pryor, N.W., Alstein, M. 2009. Evaluation of a PK/PBAN analog with an (E)-alkene, trans-Pro isostere identifies the Pro orientation for activity in four diverse pyrokinin bioassays. Peptides. 30:1254-1259.
Downer, K., Nachman, R.J., Stoffolano, J. 2007. Factors affecting engorgement behavior in the salt marsh horse fly, Tabanus nigrovittatus Macquart (Diptera: Tabanidae). Journal of Insect Behavior. 20:403-412.
Janssen, T., Meelkop, E., Nachman, R.J., Schoofs, L. 2009. Evolutionary conservation of the cholecystokinin/gastrin signaling system in nematodes. Annals of the New York Academy of Sciences. 1163:428-432.
Suh, C.P., Spurgeon, D.W. 2007. Supercooling in the adult boll weevil (Coleoptera: Curculionidae) relative to physiological condition and diet. Journal of Entomological Science. 42:320-328.
James, W.D., Showler, A.T., Westbrook, J.K., Armstrong, J.S. 2006. Stable isotope tracer marking of individual boll weevils. Journal of Radioanalytical and Nuclear Chemistry. 269(2):267-270.
Neupert, S., Russell, W.K., Russell, D.H., Strey, O., Teal, P., Strey, A.A., Nachman, R.J. 2008. Identification of a CAPA-PVK (Ixori-PVK/CAP2b) from single cells of the Gulf Coast tick, Amblyomma maculatum. Pestycydy/Pesticides. 1-2:67-73.
Suh, C.P. 2008. Relative collection efficiency of the Keep-It-Simple-Sampler for cotton fleahoppers (Hemiptera: Miridae) in cotton. Journal of Entomological Science. 43:431-433.
Taneja-Bageshwar, S., Strey, A.A., Isaac, R.E., Coast, G.M., Zubrzak, P., Pietrantonio, P.V., Nachman, R.J. 2009. Biostable agonists that match or exceed activity of native insect kinins on recombinant arthropod GPCRs. General and Comparative Endocrinology. 162:122-128.
Janssen, T., Meelkop, E., Lindemans, M., Verstraelen, K., Husson, S.J., Temmerman, L., Nachman, R.J., Schoofs, L. 2008. Discovery of a cholecystokinin-gastrin like signaling system in nematodes. Endocrinology. 144:2826-2839.
Crippen, T.L., Sheffield, C.L., Esquivel, S.V., Droleskey, R.E., Esquivel, J.F. 2009. The acquisition and internal carriage of Salmonella by lesser mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae). Vector-Borne Zoonotic Diseases. 9:65-72.
Medrano, E.G., Esquivel, J.F., Nichols, R.L., Bell, A.A. 2009. Temporal analysis of cotton boll symptoms resulting from southern green stink bug (Nezara viridula L.) feeding and transmission of a bacterial pathogen. Journal of Economic Entomology. 102:36-42.
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.