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United States Department of Agriculture

Agricultural Research Service

Title: Area-Wide Models Comparing Synchronous Versus Asynchronous Treatments for Control of Dispersing Insect Pests

Authors
item Byers, John
item Castle, Steven

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 15, 2005
Publication Date: December 1, 2005
Citation: Byers, J.A., Castle, S.J. 2005. Area-wide models comparing synchronous versus asynchronous treatments for control of dispersing insect pests. Journal of Economic Entomology 98(6): 1763:1773.

Interpretive Summary: Integrated pest management (IPM) has the goal of combining several methods that reduce populations of pest insects and their damage to tolerable levels and thereby limit the use of costly pesticides that may harm the environment. Insect populations can be monitored during the season to determine when the densities exceed an economic threshold that requires treatment, often as an insecticide application. We developed a simulation model where insect populations can vary in exponential growth in plots of a grid where varying dispersal is possible to adjacent plots each day of a season. We tested the efficacy of two models for monitoring and treatment of the plot populations, the first model monitored populations of individual plots and treated them with insecticide if they exceeded a threshold population, while the second model treated the entire grid of plots with insecticide when the average population of all plots exceeded the same threshold. We found that the second model (areawide) at all growth rates and most dispersal rates had average plot populations during a season that were significantly lower than the traditional IPM method (model 1). Also, the number of insecticide treatments was significantly less in the areawide model than the traditional method. The simulations indicate that cooperation among growers in monitoring areawide plots to obtain an average population estimate for use in treatment thresholds would result in significantly lower insect damage and insecticide treatments. The areawide cooperation is more efficient since population refugia are precluded from which dispersal could reintroduce insects.

Technical Abstract: Integrated pest management (IPM) has the goal of combining several methods that reduce populations of pest insects and their damage to tolerable levels and thereby limit the use of costly pesticides that may harm the environment. Insect populations can be monitored during the season to determine when the densities exceed an economic threshold that requires treatment, often as an insecticide application. We developed a simulation model where insect populations can vary in exponential growth in plots of a grid where varying dispersal is possible to adjacent plots each day of a season. We tested the efficacy of two models for monitoring and treatment of the plot populations, the first model monitored populations of individual plots and treated them with insecticide if they exceeded a threshold population, while the second model treated the entire grid of plots with insecticide when the average population of all plots exceeded the same threshold. We found that the second model (areawide) at all growth rates and most dispersal rates had average plot populations during a season that were significantly lower than the traditional IPM method (model 1). Also, the number of insecticide treatments was significantly less in the areawide model than the traditional method. The simulations indicate that cooperation among growers in monitoring areawide plots to obtain an average population estimate for use in treatment thresholds would result in significantly lower insect damage and insecticide treatments. The areawide cooperation is more efficient since population refugia are precluded from which dispersal could reintroduce insects.

Last Modified: 12/17/2014
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