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Evaluation of insecticide rotations and mixtures as resistance management strategies for Bemisia argentifolii (Homoptera: aleyrodidae)

Prabhake, N., Toscano, N.C., Henneberry, T.J.
Journal of economic entomology 1998 v.91 no.4 pp. 820-826
Bemisia argentifolii, bifenthrin, endosulfan, chlorpyrifos, pesticide mixtures, insecticide resistance, resistance management, insect control, application timing
A field population of Bemisia argentifolii Bellows & Perring was subjected to selective pressure with 5 insecticide regimens: continuous applications of bifenthrin, endosulfan, chlorpyrifos; bifenthrin-endosulfan-chlorpyrifos rotation and a 1:2 bifenthrin + endosulfan mixture. Insecticide resistance developed at variable rates in all whitefly populations under selection during this study. Selection with bifenthrin resulted in early resistance development that steadily increased under continuous selection to 752-fold by generation F27. With chlorpyrifos and endosulfan selection treatments, low levels of resistance developed in generations F7, and F15 respectively (resistance ratios of 8-fold). Resistance development in the rotation and mixture regimens was delayed for an additional 10 generations. The magnitude of resistance ranged from a high of 752-fold for the single continuous use of bifenthrin to a low of 16-fold resistance for the bifenthrin-endosulfan-chlorpyrifos rotation. The level of resistance was also low under selection by the bifenthrin + endosulfan mixture after 23 generations (resistance ratio = 17-fold). Compared with single, continuous insecticide selections in the greenhouse, the rate of resistance development was significantly reduced by rotations and mixtures of insecticides. For all insecticide-selection regimens, slopes of regression lines increased over many generations. The whitefly populations treated with the bifenthrin + endosulfan mixture generated the steepest lines.