Residual effectiveness of certain insecticides for controlling whitefly on cucumber plants

Document Type : Original Article

Author

Pesticide Chemistry Department, Faculty of Agriculture, El-Shatby, Alexandria University

10.21608/jpces.2000.460499

Abstract

The residual effectiveness of insecticides (pirimiphos-methyl, chlorpyrifos, cypermethrin and fenvalerate) was compared for control whitefly Bemisia spp on cucumber plants grown outdoor. Three sprays were applied of 15 days intervals. Reduction of whitefly population was estimated after each spray. The highest reduction of Bemisia spp population was 83.2, 83.0, 73.9 and 56.6 at pirimiphos-methyl, chlorpyrifos, cypermethrin and fenvalerate treatments, respectively after one day post the first spray. The reduction percentage declined afterwards and reached approximately 8-10 % after 15 days post treatments. The same trend was observed after the second and the third spray in which the highest reduction was achieved at the first day after insecticide applications. In the meantime inadequate reduction was observed after three days from treatment. The remaining residues of cypermethrin on the cucumber leaves were more than that of pirimiphos-methyl. However, the rate of decay of cypermethrin on cucumber leaves was slightly higher than that of pirimiphos-methyl. Moreover, the t½ was 2.1 and 3.15 day for cypermethrin and pirimiphos-methyl, respectively, under the field conditions.

Keywords

Journal of Pest Control and Environmental Sciences
Volume 8, Issue 2
August 2000
Pages 29-44

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