2009 Annual Report
1a.Objectives (from AD-416)
Investigate, develop and evaluate the use of predators, parasitoids, entomopathogens, feeding stimulants or deterrents, cultural controls, host resistance, and other environmentally -friendly tactics in IPM programs for Colorado potato beetle, corn rootworm and other chrysomelid pests.
Develop methods for improved management of gypsy moths in non-forest and newly infested forested areas of the United States, particularly mating disruption techniques.
1b.Approach (from AD-416)
Characterize and develop new tactics to manage chrysomelid leaf beetles, particularly Colorado potato beetle and corn rootworms, and in laboratory, semi-field and field experiments, evaluate various methods of deployment, such as primary toxicants or pathogens, habitat augmentation, conservation biocontrol, baits or other attracticidal formulations, or incorporation in crop or trap plants. Studies will encompass biology, host specificity, behavior, non-target effects and environmental impact of biological control agents and other tactics. Studies will be conducted in cooperation with U.S. Forest Service "slow the spread" national Gypsy Moth Project and partners to disrupt gypsy moth mating.
During fiscal year 2009, research progress was made towards developing effective, environmentally sound biological controls, through natural and biotechnological methods, for use against agricultural pests.
To address our goal of characterizing natural enemies which function as biological controls of pests, we have: (1) demonstrated how laboratory studies on predator digestive rate can be used to correctly determine the relative role of different predators in controlling a pest based on analysis of prey molecular marker remains in their stomachs; (2) documented pest and natural enemy response to cover crop treatments, as well as intraguild predation (consumption of predators by other predators), and (3) used discoveries of plant defense mechanisms to devise methods of transforming plants with inducible plant defenses, which are activated only when attacked by pests. Scientists determined important factors affecting measurement of predation by quantitative PCR for the key predator Coleomegilla maculata, and are expanding this work to include other foods such as pollen, aphids, and yeast, to gain insight into omnivory, which is often important for generalist predators. Molecular methods for identifying predators and quantifying predation have been improved greatly by IIBBL contributions. Regarding crop hosts and resistance, researchers at IIBBL have cloned the regulatory region of an infestation-induced gene from poplar and transformed Arabidopsis with this transgene, with the result that the marker gene was expressed upon infestation.
Identifying the defense genes induced in potatoes to Colorado potato beetle (CPB) feeding. In order to find potato genes affected by CPB feeding, IIBBL scientists and collaborators from TIGR (The Institute of Genomic Research) and from the University of Alberta, in Edmonton Alberta, Canada conducted and analyzed 11,421 genes of potato and identified 320 genes in potato leaves affected by CPB feeding. Many of the genes found have been implicated in a general defense response, while two genes encode proteins that produce volatiles known to attract CPB predators. Comparing continuous attack versus recovery from CPB attack indicates that fewer genes are induced by continuous feeding, suggesting that the defense response is enhanced under light versus heavy attack. This work will allow the future cloning of regulatory regions from these induced genes. Ultimately this will allow the production of a transgene with inducible resistance to CPB, which will lower the amount of insecticidal toxin in the environment.
Predation detection by PCR, and correction of raw gut analysis data to account for differences in DNA digestion rate. IIBBL scientists, in collaboration with other ARS and university scientists, determined that rates of Colorado potato beetle DNA digestion differ by more than a factor of ten in the adults and larvae of the four key predator species of this pest. Using this information to correct raw data on predation rates by predators collected in the field, they were able to correctly rank the predator species by their importance in controlling the pest.
Harwood, J.D., Desneux, N., Yoo, H.S., Rowley, D.L., Greenstone, M.H., Obrycki, J.J., O'Neil, R.J. 2007. Tracking the role of alternative prey in soybean aphid predation by prius insidiosus: a molecular approach. Molecular Ecology. 16:4390-4400.
Harwood, J.D., Yoo, H., Greenstone, M.H., Rowley, D.L., O'Neil, R.J. 2008. Differential impact of adults and nymphs of a generalist predator on an exotic invasive pest demonstrated by molecular gut-content analysis. Biological Invasions. http://dx.doi.org/10.1007/s10530-008-9302-6.
Lawrence, S.D., Novak, N.G., Ju, C., Cooke, J. 2008. Examining the molecular interaction between potato (solanum tuberosum) and colorado potato beetle
leptinotarsa decemlineata. Botany. 86:1080-1091. http://dx.doi.org/10.1139/B08-074.
Lawrence, S., Novak, N., Ju, C., Cooke, J. 2008. Potato, Solanum Tuberosum, defense against Colorado potato beetle, Leptinotarsa decemlineata (Say): Microarray gene expression profiling of potato by Colorado potato beetle regurgitant treatment of wounded leaves. Journal of Chemical Ecology. 34(8)1013-1025.
Weber, D.C., Chaboo, C.S., Saska, P. 2008. Carabid beetles as parasitoids. Encyclopedia of Entomology. 2:35-37.
Weber, D.C. 2008. Colorado potato beetle. Encyclopedia of Entomology. 2:324-328.
Chauhan, K.R., Weber, D.C. 2008. Lady beetle (coleoptera: coccinellidae) tracks deter oviposition by the goldeneyed lacewing, chrysopa oculata. Biocontrol Science and Technology. 18(7):727-731
Toepfer, S., Haye, T., Erlandson, M., Goettel, M., Lundgren, J.G., Kleespis, R.G., Weber, D.C., Cabrera-Walsh, G., Jackson, J.J., Peters, A., Vidal, S., Strasser, H., Ehlers, R.V., Moore, D., Keller, S., Kuhlmann, V. 2009. A Review of the Natural Enemies of Beetles in the Subtribe Diabroticina (Coleoptera: Chrysomelidae): Implications for Sustainable Pest Management. Biocontrol Science and Technology. 19(1): 1-65.
Szendrei, Z., Weber, D. 2009. Response of predators to habitat manipulation in potato fields. Biological Control. 50(2):123-128. Available www.sciencedirect.com/science?.
Weber, D., and Lundgren, J. 2009. Assessing the trophic ecology of the
coccinellidae: their roles as predators and as prey. Biological Control. 51: 199-214. http://dx.doi.org/10.1016/j.biocontrol.2009.05.013.
Biddinger, D.J., Weber, D.C. Weber, and Hull, L.A. 2009. Coccinellidae as predators of mites: Stethorini in biological control. Biological Control. 51: 268-283. http://dx.doi.org/10.1016/j.biocontrol.2009.05.014.
Harwood, J.D., Greenstone, M.H. 2008. Molecular diagnosis of natural enemy-host interactions. In: Lie, I.N., editor. Recent Advances in Insect Physiology, Toxicology and Molecular Biology. Kerala, India. Research Signpost. p. 41-57.
Weber,D.C., and Lundgren, J.G., 2009. Detection of predation using qPCR: effect of prey quantity, elapsed time, chaser diet, and sample preservation on detectable quantity of prey DNA. Journal of Insect Science. 9(41). Available http://www.insectscience.org/9.41.