Esfenvalerate Residues on Pepper and Pumpkin Following Application for Control of Cucumber Beetles (Coleoptera: Chrysomelidae)

Esfenvalerate was sprayed on green pepper and pumpkin plants at 7.0 g (AI)/ha to control adult striped cucumber beetle, Acalymma vittatum (Fabricius), and spotted cucumber beetle, Diabrotica undecimpunctata howardi (Barber). Following spraying, residues of esfenvalerate on the two crops were determined and adult insects were swept and counted. Esfenvalerate was extracted using n-hexane from representative plant samples collected at different time intervals following spaying for residue analysis. Determination of residues using gas chromatography (GC-ECD) indicated initial deposits of 3.34 and 1.18 ppm on pumpkin and pepper leaves, respectively. Only trace levels were detected on pepper fruits on day 21 (0.0001 ppm). Half-life values were 1.11 and 2.79 d on pumpkin and pepper fruits, respectively, whereas the values were 1.92 and 3.38 d on pumpkin and pepper leaves, respectively. Periodic sweep-net collections from treated and untreated plots revealed mean beetle reductions of nearly 100% 1 h post-treatment and > 60% 2 wk after treatment on both crops. Results obtained may be useful for developing IPM strategies to reduce pesticide residues on produce.