Progress 10/01/00 to 09/30/04
Outputs
Convincing evidence was generated documenting that previous feeding by potato leafhopper induces physiological changes in potato foliage that adversely affect the performance and survival of Colorado potato beetle which feeds later in the season on the same plants. As a result, leafhoppers and Colorado potato beetles compete with one another via induced plant resistance. The mechanism underlying the plant-mediated induced resistance likely involves altered plant nutrition or possibly allelochemistry. Moreover, the delayed development of Colorado potato beetle resulting from previous leafhopper feeding enhances the risk of beetle attack from natural enemies such as heteropteran predators. Thus, previous feeding by leafhoppers results in both negative direct effects on beetle performance and indirect effects resulting from increased mortality due to natural enemies. Such interactive effects (induced resistance effects) are not currently used to establish economic
thresholds for potato leafhopper. This research has developed a framework for a more accurate economic threshold for potato leafhopper, one that takes into account both the direct impact of leafhopper feeding on potato yield and the indirect benefit of diminished Colorado potato beetle populations on leafhopper-induced plants. This research ultimately aimed to minimize insecticide use through the intra-seasonal management of a complex of agricultural pests.
Impacts
Data will ultimately be used to modify economic injury levels for PLH and develop more accurate decision-making models for PLH management. More specifically, our resulting research suggests that leafhopper economic thresholds should be raised to account for their adverse effects on Colorado potato beetles, which has more devastating effects on potatoe production than do leafhoppers.
Publications
- Denno, R.F., M.S. Mitter, G.A. Langellotto, C. Gratton, and D.L. Finke. 2004. Interactions between a hunting spider and a web-builder: consequences of intraguild predation and cannibalism for prey suppression. Ecological Entomology 29: 566-577.
- Olson, E. R., G. P. Dively, and J. O. Nelson, 2004, Bioassay determination of the distribution of imidacloprid in potato plants: implications to resistance development. J. Econ. Entomol. 97: 614-620
- Finke, D.L. and R.F. Denno. 2005. Predator diversity and the functioning of ecosystems: the role of intraguild predation in dampening trophic cascades. Ecology Letters 8: 1299-1306.
- Denno, R.F., C. Gratton, H. Doebel, and D.L. Finke. 2003. Predation risk affects relative strength of top-down and bottom-up impacts on insect herbivores. Ecology 84: 1032-1044.
- Gratton, C. and R.F. Denno. 2003. Seasonal shift from top-down to bottom-up impact in phytophagous insect populations. Oecologia 134: 487-495.
- Denno, R.F. and W.F. Fagan. 2003. Might nitrogen limitation promote omnivory among carnivorous arthropods. Ecology 84: 2522-2531 (Invited Special Feature)
- Eubanks, M.D., J.D. Styrsky, and R.F. Denno. 2003. The evolution of omnivory in heteropteran insects. Ecology 84: 2549-2556. (Invited Special Feature)
- Roderick, G.K., L. Garcia de Mendoza, G.P. Dively, and P. A. Follett. 2003. Sperm precedence in Colorado potato beetle (Coleoptera: Chrysomelidae): temporal variation assessed by neutral markers. Annals Entomol. Soc. Amer. 96: 631-636.
- Langellotto, G.A. and R.F. Denno. 2004. Responses of invertebrate natural enemies to complex-structured habitats: A meta-analytical synthesis. Oecologia 139: 1-10.
- Finke, D.L. and R.F. Denno. 2004. Predator diversity dampens trophic cascades. Nature 429: 407-410.
- Fagan, W.F. and R.F. Denno. 2004. Stoichiometry of actual versus potential predator-prey interactions: insights into nitrogen limitation for arthropod predators. Ecology Letters 7: 876-883.
- Matsumura, M., G.M. Trafelet-Smith, C. Gratton, D.L. Finke, D.L. Finke, W.F. Fagan, and R.F. Denno. 2004. Does intraguild predation enhance predator performance? A stoichiometric perspective. Ecology 89: 2601-2615.
- Denno, R.F., D.L. Finke, and G.A. Langellotto. 2005. Direct and indirect effects of vegetation structure and habitat complexity on predator-prey and predator-predator interactions. Pages 211-239 In P. Barbosa and I. Castellanos, eds. Ecology of Predator-Prey Interactions. Oxford University Press, London, UK.
- Prasifka, J. R., R.L. Hellmich, G. P. Dively, and L. C. Lewis. 2005. Assessing the effects of pest management on nontarget arthropods: the influence of plot size and isolation. Environ. Entomol. 34: 1181-1192.
- Lynch, M.E., I. Kaplan, G.P. Dively, and R.F. Denno. 2006. Host plant-mediated competition via induced resistance: interactions between pest herbivores on potatoes. Ecological Applications 16: 855-864.
- Finke, D.L. and R.F. Denno. 2006. Spatial refuge from intraguild predation: implications for prey suppression and trophic cascades. Oecologia 149: 265-275.
- Denno, R.F. and I. Kaplan. 2007. Plant-mediated interactions in herbivorous insects: mechanisms, symmetry, and challenging the paradigms of competition past. Pages 19-50 In T. Ohgushi, T.A. Craig, and P.W. Price, eds. Ecological communities: plant mediation in indirect interaction webs. Cambridge University Press, London, UK.
- Langellotto, G.A. and R.F. Denno. 2006. Refuge from cannibalism in complex-structured habitats: implications for the accumulation of invertebrate predators. Ecological Entomology 31: 575-581.
- Denno, R.F. and D.L. Finke. 2006. Multiple predator interactions and food-web connectance: implications for biological control. Pages 45-70 In J. Brodeur and G. Boivin, eds. Trophic and guild interactions in biological control. Springer, Dordrecht, Netherlands.
- Kaplan, I., M.E. Lynch, G.P. Dively, and R.F. Denno. 2007. Leafhopper-induced plant resistance enhances predation risk in a phytophagous beetle. Oecologia(in press)
- Alyokhin, A., G.P. Dively, M. Patterson, D. Rogers, M. Mahoney, and J. Wollam. 2007. Susceptibility of Imidacloprid-Resistant Colorado Potato Beetles to Non-neonicotinoid Insecticides in the Laboratory and Field Trials. American Journal of Potato Research 83:485-49.
- Kaplan, I., R. Halitschke, A. Kessler, S. Sardanelli, and R.F. Denno. 2007. Constitutive and induced defenses to herbivory in above- and belowground plant tissues. Ecology (submitted)
- Kaplan, I, and R.F Denno. 2007. Interspecific interactions in phytophagous insects revisited: a quantitative assessment of competition theory. Ecology Letters (submitted)
|
Progress 01/01/02 to 12/31/02
Outputs
Results to date are as follows: (1) Previous feeding by PLH induces changes in potato that dissuade oviposition by CPB and (2) CPB larvae develop slower and exhibit reduced survival on PLH-induced potato plants. These results demonstrate unequivocally the adverse effects that PLH feeding has on CPB in both laboratory cages and large open plots in the field. Also, other experiments have been completed testing the interactive effects of PLH feeding and predator presence on the survival of CPB via altered risk of predation. Currently, data for this experiment are being analyzed rigorously, but preliminary results suggest that PLH indirectly affects CPB survival by extending exposure to natural enemies.
Impacts
Data will ultimately be used to modify economic injury levels for PLH and develop more accurate decision-making models for PLH management.
Publications
- Denno, R.F., and M.A. Peterson. 2000. Caught between the devil and the deep blue sea, mobile planthoppers elude natural enemies and deteriorating host plants. American Entomologist 46: 95-109.
- Eubanks, M.D. and Robert F. Denno. 2000. Host plants mediate omnivore-herbivore interactions and influence prey suppression. Ecology 81: 936-947.
- Denno, R.F., C. Gratton, H. Dobel, and D.L. Finke. 2003. Predation risk affects relative strength of top-down and bottom-up impacts on insect herbivores. Ecology 84: 1032-1044.
- Finke, D.L. and R.F. Denno. 2003. Intraguild predation relaxes natural enemy impacts on herbivore populations. Ecological Entomology 28: 67-73.
- Gratton, C. and R.F. Denno. 2003. Seasonal shift from top-down to bottom-up impact in phytophagous insect populations. Oecologia 134: 487-495.
- Denno, R.F. and W.F. Fagan. 2003. Might nitrogen limitation promote omnivory among carnivorous arthropods. Ecology (Invited Special Feature)
- Eubanks, M.D., J.D. Styrsky, and R.F. Denno. 2003. The origin of omnivory: historical factors that promote omnivory in heteropteran insects. Ecology (Invited Special Feature) In press
- Gratton, C. and R.F. Denno. 2003. Inter-year carryover effects of a nutrient pulse on Spartina plants, herbivores, and natural enemies. Ecology In press
- Stanley-Horn, D.E., G.P. Dively, R.L. Hellmich, H.R. Mattila, M.K. Sears, R.Rose, L.C.H. Jesse, J.E. Losey, J.J. Obrycki, and L. Lewis. 2001. Assessing the impact of Cry1Ab-expressing corn pollen on monarch butterfly larvae in field studies. Proc. Natl. Acad. Sci. USA, 98: 11931-11936.
|
Progress 01/01/01 to 12/31/01
Outputs
Colorado potato beetle (CPB) and potato leafhopper (PLH) are both major pests of potatoes. PLH and CPB appear to compete with one another via induced plant resistance. Because induced plant resistance can delay the development of a later-feeding herbivore, its risk of attack from natural enemies may be enhanced as well. Thus, early-season infestation of potato by PLH, although it can have direct negative effects on potato yield, may have delayed benefits measured in terms of decreased beetle density. Notably, such interactive effects are not currently considered in making management decisions for PLH or other pests in most cropping systems. Using a combination of experiments, we address two major objectives. First, we thoroughly investigate the PLH-CPB interaction and take advantage of the ideal opportunity it offers to study both the direct (results presented here) and indirect effects of induced plant resistance (this summers research). Second, we propose to develop
the framework for a contemporary economic injury level and set of management decision rules for PLH which reflect the benefits derived from induced resistance to CPB (this summers research). Results to date show that CPB performs better and prefers to oviposit on plants that do not have high levels of PLH damage. CPB mortality was significantly higher on those plants that were highly damaged by PLH. By contrast, CPB fed plants without leafhopper damage exhibited high survivorship. Results also indicate that CPB development time was extended for beetles fed PLH-damaged potato plants. Lastly, our results show that when given the choice, CPB prefers to oviposit on potato foliage not exposed to previous feeding by leafhoppers. These results provide strong evidence that leafhoppers induce changes in potato physiology that have adverse effects on CPB performance and oviposition preference.
Impacts
Our underlying goal with the incorporation of induced plant resistance into management decisions is to reduce the need for insecticide treatments for both pests (Potato Leafhopper and Colorado Potato Beetle, which simultaneously lowers the risks of resistance development and enhances the potential mortality from natural enemies.
Publications
- Denno, R.F., M.A. Peterson, C. Gratton, J. Cheng, G.A. Langellotto, A.F. Huberty, and D.L. Finke. 2000. Feeding-induced changes in plant quality mediate interspecific competition between sap-feeding herbivores. Ecology 81: 1814-1827.
- Eubanks, M.D. and Robert F. Denno. 2000. Health food versus fast food: the effects of prey quality and mobility on prey selection by a generalist predator and indirect interactions among prey species. Ecological Entomology 25: 140-146.
- Elser, J.J., W.F. Fagan, R.F. Denno, D.R. Dobberfuhl, A. Folarin, A.F. Huberty, S. Interlandi, S.S. Kilham, E. McCauley, K.L. Schultz, E.H. Siemann, and R.W. Sterner. 2000. Nutritional constraints in terrestrial and freshwater food webs. Nature 408: 578-580.
- Langellotto, G.A. and Denno, R.F. 2001. Benefits of dispersal in patchy environments: Mate location by males of a wing-dimorphic insect. Ecology 82:1870-1878.
- Finke, D.L. and R.F. Denno. 2002. Intraguild predation diminished in complex-structured vegetation: Implications for prey suppression. Ecology 83:643-652.
- Denno, R.F., C. Gratton, M.A. Peterson, G.A. Langellotto, D.L. Finke, and A.F. Huberty. 2002 (In press). Bottom-up forces mediate natural-enemy impact in a phytophagous insect community. Ecology
- Fagan, W.F., E. Siemann, C. Mitter, R.F. Denno, A.F. Huberty, H.A. Woods, and J.J. Elser. 2002 (In press). Nitrogen in insects: implications for trophic complexity and species diversification. The American Naturalist
- Denno, R.F. and W.F. Fagan. 2002 (In press). A stoichiometric perspective on omnivory in arthropod-dominated ecosystems: the importance of nitrogen limitation. Ecology (Invited Special Feature)
- Gratton, C. and R.F. Denno. 2002 (In press). Seasonal shift from top-down to bottom-up impact in a phytophagous insect community. Ecology
- Denno, R.F. and M. A. Peterson. 2002 (In press). From ecosystems to molecules: cascading effects of habitat persistence on dispersal strategies and the genetic structure of populations. Pages xxx-xxx In A. Moya and E. Font, eds. Evolution, from molecules to ecosystems. Oxford University Press, London.
- Nault, B.A., J. Speese III, G.G. Kennedy, J. J. Linduska, and G. P. Dively. 2002. Response of potato tuber yield to stem injury by European corn borer (Lepidoptera: Pyralidae) in the mid-Atlantic U.S. J. Econ. Entomol. (Accepted).
- Sears, M.K., R. L. Hellmich, D.E. Stanley, Horn, K.S. Oberhauser, J=M. Pleasants, H.R. Mattila, B.D. Siegfried, and G.P. Dively. 2001. Impact of Bt corn pollen on monarch butterfly populations: A risk assessment. Proc. Natl. Acad. Sci. USA, 98:11937?11942.
- D.E. Stanley?Horn, G.P. Dively, R.L. Hellmich, H.R. Mattila, M.K. Sears, R.Rose, L.C.H. Jesse, J.E. Losey, J.J. Obrycki, and L. Lewis. 2001. Assessing the impact of Cry1Ab expressing corn pollen on monarch butterfly larvae in field studies. Proc. Natl. Acad. Sci. USA, 98: 11931-11936. J.M. Pleasants, R.L. Hellmich, G.P. Dively, M.K. Sears, D.E. Stanley, Horn, H.R. Attila, J.E. Foster, P.Clark, and G.D. Jones. 2001. Corn pollen deposition on milkweeds in and near cornfields. Proc. Natl. Acad. Sci. USA, 98:11919-11924.
- K.S. Oberhauser, M.D. Prysby, H.R. Mattila, D.E. Stanley, Horn, M.K. Sears, G.P. Dively, E. Olson, J. M. Pleasants, W.F. Lam, and R.L. Hellmich. 2001. Temporal and spatial overlap between monarch larvae and corn pollen. Proc. Natl. Acad. Sci. USA, 98: 11913-11918.
- Riddick, E. W., G. P. Dively, and P. Barbosa. 2000. Season-long abundance of generalist predators in transgenic versus nontransgenic potato fields. J. Entomol. Sci. 35:349-359.
- Semtner, P.J., T.D. Reed, D. Conrad, and G.P. Dively. 2002. Insect control in Tobacco. In: 2000 Pest Management Recommendations for Field Crops. MD Coop. Ext. Ser. Bull. 237, section 4, pp 41-51 (revised annually).
- Dively, G.P. and G.F. Chappell II. 2002. Insect pest management guidelines for stored grain. In: 2002 Pest Management Recommendations for Field Crops. MD Coop. Ext. Ser. Bull. 237, section 4, pp 52-57 (revised annually).
- McClurg, C.A., C.E. Beste, R.J. Rouse, J.J. Linduska, J.G. Kantzes, A.E. Brown, and G.P. Dively. 2002. Commercial Vegetable Production Recommendations. MD Coop. Ext. Ser. Bull. 236. 119 pp. (Joint publication with New Jersey, Delaware, and Virginia; revised annually.
- Dively, G.P. and T. Patton. 2001. Resurgence of the Hessian fly, pp 5. In: 2000 Integrated Pest Management Progress Report. MD Coop. Ext. Special Report. 37 pp.
- Olson, E. R., G. P. Dively, and J. O. Nelson. 2000. Baseline susceptibility to imidacloprid and cross resistance patterns in Colorado potato beetle (Coleoptera: Chrysomelidae) populations. J. Econ. Entomol. 93: 447-458.
- Roderick, G.K., L. Garcia de Mendoza, P.A. Follett, and G.P. Dively. 2002. Sperm precedence in Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae): temporal variation assessed by neutral markers. Ann. Entomol. Soc. Am. (in press).
- Dively, G.P., J.M. Whalen, A.D. Herbert, and R. Youngman. 2002. Insect pest management for field crops. In: 2002 Pest Management Recommendations for Field Crops. MD Coop. Ext. Ser. Bull. 237, section 4, pp 1-40.
- Beste, C.E., D. Caron, G.P. Dively, K. Everts, E. Kee, S.D. Walker, J. Whalen, J. Windsor, and T. Wootten. 2000. Watermelon Production Guide for Delaware and Maryland. DE Ext. Ser. Bull. (on-line) 57 pp. (Joint publication with Delaware). http://www.rec.udel.edu/veggie/watermelon/watermelonproductionguide.p df
- Dively, G.P. and T. Patton. 2001. The cereal rust mite?a major constraint on timothy hay production, pp 6. In: 2000 Integrated Pest Management Progress Report. MD Coop. Ext. Special Report. 37 pp.
- Dively, G.P. 2001. Implementing successful management practices on potatoes, pp 7. In: 2000 Integrated Pest Management Progress Report. MD Coop. Ext. Special Report. 37 pp.
- Everts, K.L., B. Gallagher, R.J. Kratochvil, S. Sardanelli, and G.P. Dively. 2001. Exploring alternative nematode management tactics, pp 9. In: 2000 Integrated Pest Management Progress Report. MD Coop. Ext. Special Report. 37 pp.
|