Monday, December 11, 2006 - 9:47 AM

Effect of operational factors on the evolution of resistance to an insect growth regulator by the sweetpotato whitefly

David W. Crowder,, Yves Carrière,, Bruce E. Tabashnik,, Timothy J. Dennehy,, and Peter C. Ellsworth, University of Arizona, 410 Forbes Bldg, University of Arizona Dept of Entomology, Tucson, AZ

We used computer simulations to examine the effect of action thresholds and landscape diversity on the evolution of resistance to the insect growth regulator pyriproxyfen by the sweetpotato whitefly, Bemisia tabaci (Gennadius), biotype B (=Bemisia argentifolii [Bellows & Perring]). Lower action thresholds for using pyriproxyfen slowed the evolution of resistance, as population densities in treated fields decreased compared to densities in refuges when action thresholds were decreased. However, lower action thresholds for using pyriproxyfen resulted in more insecticide applications per year. Resistance evolved slowest in regions in which multiple crops were grown throughout the year, followed by regions with spring crops and then cotton. Resistance evolved fastest in cotton-intensive regions. These results show that non-biological factors may contribute to evolution of resistance to pyriproxyfen.

Species 1: Hemiptera aleyrodidae bemisia tabaci (sweet potato whitefly)

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