2007 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.
Minimal Boll Weevil Survival on Non-Fruiting Regrowth Cotton:
Regrowth of cotton following harvest is a concern of boll weevil eradication programs because such plants may extend the opportunity for weevils to reproduce or acquire the necessary fat reserves to overwinter. Most of the concern is directed toward fruiting regrowth cotton because non-fruiting plants cannot support weevil reproduction; however, questions remain regarding the potential contribution of non-fruiting regrowth to weevil host-free survival. Scientists in the Areawide Pest Management Research Unit at the Southern Plains Agricultural Research Center, College Station, TX, demonstrated that only a very small proportion of boll weevils have the ability to feed on non-fruiting regrowth plants and accumulate the necessary fat reserves to extend host-free survival. These findings are important because they will facilitate development of more effective strategies for use by boll weevil eradication programs in managing the weevil, particularly in areas that have experienced unsatisfactory progress in eradication, or that have experienced resurgence of weevil populations. (NP 304, Component 2, Problem Statement 2A)
Non-Cotton Hosts for the Tarnished Plant Bug:
The tarnished plant bug has reached pest status in cotton in those areas where insecticide applications have been reduced because of.
1)the success of boll weevil eradication efforts,.
2)the implementation of Bt crops, and/or.
3)the use of selective insecticides for lepidopteran pests. It is important that host plants for the tarnished plant bug be identified so that areawide management programs can be developed for control of the bug on non-cotton host plants before the insect can infest fruiting cotton. Scientists in the Areawide Pest Management Research Unit at the Southern Plains Agricultural Research Center, College Station, TX, demonstrated that the tarnished plant bug was the only species of the Lygus genus that occurs in Central Texas, and identified its non-cotton host plants at different seasons of the year. Because of the recent elevation of the tarnished plant bug to cotton pest status, this accomplishment is important because it clearly defines those host plants sought out by the bug, and identifies targets for control emphasis prior to the bug infesting and causing major damage to cotton. (NP 304, Component 3, Problem Statement 3B)
Microscopic Techniques for Pollen Analysis of Stink Bugs:
The southern green stink bug can be an important pest of cotton, particularly in areas where the boll weevil has been eradicated and insecticide applications have been reduced. Better methods to assess the habitat preferences and food sources for the bug are needed to more completely understand its biology and to aid in development of effective control procedures. Instrumentation including the scanning electron microscope (SEM) and the environmental scanning electron microscope (ESEM) have been effectively used to identify pollen found on numerous insect pests, and which implicates host plants of the insects. However, the secretion of oils by stink bugs damages SEM and ESEM, which prevents viewing of the insects for the presence/identification of pollen grains adhering to them. Scientists in the Areawide Pest Management Research Unit at the Southern Plains Agricultural Research Center, College Station, TX, developed an effective technique that removes pollen from southern green stink bugs so that it can be accurately identified (to the plant species level) using SEM and/or ESEM. This accomplishment is important because it will greatly facilitate identification of preferred host plants used at different seasons by stink bugs, and it will help in development of effective strategies for management of this emerging crop pest. (NP 304, Component 3, Problem Statement 3B)
Biostable Versions of Water Regulating Insect Neuropeptides:
Neuropeptides are short chains of amino acids that regulate critical life functions in insects. However, biostable versions of neuropeptides, which can resist degradation by enzymes in insects, will be required in order for neuropeptide technology to be developed for effective pest insect control. Scientists in the Areawide Pest Management Research Unit at the Southern Plains Agricultural Research Center, College Station, TX, in collaboration with scientists at the University of London, England, used a novel strategy that involves use of non-natural variants of amino acids known as 'beta' amino acids to create the biostable versions. Two of the synthesized neuropeptide versions were shown to be as potent as natural neuropeptides in regulating water balance in a variety of insects. Further, they were found to be stable to internal insect factors that inactivate the natural neuropeptides. The accomplishment is important because it brings us one step closer to the development of practical neuropeptide-like substances that will disrupt normal water balance and effectively control pest insects in an environmentally friendly fashion. (NP 304, Component 2, Problem Statement 2A)
Dynamics of Boll Weevil Pheromone Production:
It is universally accepted that boll weevils require access to food to produce pheromones (volatile attractants) that are used by the insects to aggregate populations. However, more information is needed about the timing and intensity of pheromone release. Scientists in the Areawide Pest Management Research Unit at the Southern Plains Agricultural Research Center, College Station, TX, demonstrated a daily pattern of pheromone production by the boll weevil, and illustrated the need to carefully control the feeding schedule and diet in pheromone production studies. This work provides important new knowledge and insight on the chemical ecology of boll weevils, it will lead to improved trapping methods, and it will ultimately facilitate development of more effective procedures/protocols for eradication of the boll weevil from the U.S. (NP 304, Component 2, Problem Statement 2A)
|Number of U.S. patents granted||1|
|Number of web sites managed||1|
|Number of non-peer reviewed presentations and proceedings||17|
|Number of newspaper articles and other presentations for non-science audiences||8|
Predel, R., Russell, W.K., Neupert, S., Russell, D.H., Esquivel, J.F., Nachman, R.J. 2006. Identification of the first neuropeptides from the CNS of Hemiptera: CAPA peptides of the southern green stinkbug Nezara viridula (L.). Peptides. 27:2670-2677.
Esquivel, J.F., Mowery, S.V. 2007. Host plants of the tarnished plant bug (Heteroptera: Miridae) in Central Texas. Environmental Entomology. 36:725-730.
Nachman, R.J., Coast, G.M. 2007. Structure-activity relationships for in vitro diuretic activity of CAP2b in the housefly. Peptides. 28:57-61.
Nachman, R.J., Fehrentz, J., Martinez, J., Kaczmarek, K., Zabrocki, J., Coast, G.M. 2007. A C-terminal aldehyde analog of the insect kinins inhibits diuresis in the housefly. Peptides. 28:146-152.
Downer, K.E., Haselton, A.T., Nachman, R.J., Stoffolano, J.G. 2006. Insect satiety: Sulfakinin localization and the effect of drosulfakinin on protein and carbohydrate ingestion in the blow fly, Phormia regina (Diptera: Calliphoridae). Journal of Insect Physiology. 53:106-112.
Predel, R., Neupert, S., Russell, W.K., Schreibner, O., Nachman, R.J. 2007. Corazonin in insects. Peptides. 28:3-10.
Kaczmarek, K., Williams, H.J., Coast, G.M., Scott, A.I., Zabrocki, J., Nachman, R.J. 2007. Comparison of insect kinin analogs with cis-peptide bond motif 4-aminopyroglutamate identifies optimal stereochemistry for diuretic activity. Biopolymers. 88:1-7.
Poels, J., Verlinden, H., Fichna, J., Loy, T.V., Franssens, V., Studzian, K., Janecka, A., Nachman, R.J., Broeck, J.V. 2007. Functional comparison of two evolutionary conserved insect neurokinin-like receptors. Peptides. 28:103-108.
Suh, C.P. 2007. Head capsule widths of nymphal instars of the cotton fleahopper. Southwestern Entomologist. 32:127-130.
Spurgeon, D.W., Suh, C.P. 2007. Diel patterns of pheromone production in the boll weevil (Coleoptera: Curculionidae). Journal of Entomological Science. 42:250-260.
Spurgeon, D.W., Raulston, J.R. 2006. Boll weevil (Coleoptera: Curculionidae) adult diapause responses to selected environmental and dietary conditions. Annals of the Entomological Society of America. 99:1085-1100.
Suh, C.P., Spurgeon, D.W. 2006. Host-free survival of boll weevils (Coleoptera: Curculionidae) previously fed vegetative-stage regrowth cotton. Journal of Entomological Science. 41:277-284.
Spurgeon, D.W. 2007. Ecologically-based IPM in cotton. In: Koul, O., Cuperus, G.W., editors. Ecologically-Based Integrated Pest Management. Wallingford, UK: CABI Publishing. p. 367-405.
Zubrzak, P., Williams, H., Coast, G.M., Isaac, R.E., Reyes-Rangel, G., Juaristi, E., Zabrocki, J., Nachman, R.J. 2007. Beta-amino acid analogs of an insect neuropeptide feature potent bioactivity and resistance to peptidase hydrolysis. Biopolymers. 88:76-82.
Jones, G.D., Bryant, V.M. 2007. A comparison of pollen counts: Light versus scanning electron microscope. Grana. 46:20-33.
Predel, R., Nachman, R.J. 2006. The fxprlamide (pyrokinin/pban) peptide family. In: Kastin, A., editor. Handbook of Biologically Active Peptides. New York, NY: Elsevier. p. 207-213.
Schoofs, L., Nachman, R.J. 2006. Sulfakinins. In: Kastin, A., editor. Handbook of Biologically Active Peptides. New York, NY: Elsevier. p. 183-189.
Medrano, E.G., Esquivel, J.F., Bell, A.A. 2007. Transmission of cotton seed and boll rotting bacteria by the southern green stink bug (Nezara viridula L.). Journal of Applied Microbiology. 103:436-444.