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USEPA Resistance Management Model development
Citation:
GLASER, J. A. AND M. Caprio. USEPA Resistance Management Model development. Presented at ORD/OPPTS Seminar USEPA Resistance Model Development, Washington , DC, January 17, 2008.
Impact/Purpose:
To inform the public
Description:
The US EPA requires registrants of plant incorporated protectant (PIP) crops to provide information relating to the time frame for pest resistance development related to the control traits of the crop. Simulation models are used to evaluate the future conditions for resistance development. These models can be useful to anticipated efforts of enforcement related to stewardship requirement such as refuge. This research effort was designed to develop a model for EPA’s use in the regulatory and research communities. This tool is anticipated to be the first of several related to the needs of regulatory, enforcement and research efforts connected to pest management for PIP crops. EPA-Popgen, a population genetics simulation, is a flexible, spatially complex, individually based simulation model. It can simulate any number of different habitats in a growing area. The model has the capability of examining selection in complex mixtures of habitats, each patch connected to the others in the system through dispersal. The major processes within the model are mating, reproduction, ageing (including pesticide induced mortality), and dispersal. Each of these processes is stochastic and the result of a binomial draw. The model is individual-based to the degree that counts of individual insects are maintained (though grouped by age and genotype within a patch), and there are no fractional individuals or alleles. The latter provision has significance in that rare alleles frequently go extinct when population sizes are reduced due to intense selection, though this is less likely to occur in larger systems (and probably in nature). The flexibility of the model is also increased because relatively few parameters are compiled into the program (number of fields and overwintering time are some of those). Most parameters are entered in through a separate java-based user interface which has been developed as part of this research collaboration. These parameters include the biological descriptions of the various habitats and the number and placement of the patches. This design minimizes the need for frequent recompilation once the model has been adapted for a particular insect. This model can be deployed on an EPA server to provide access to parties interested in its utility to a variety of agency issues. A logical extension to include model capabilities to address the more complex trait structure of new PIP crops is anticipated to be undertaken this year.