Toxicity of Avermectin B1 to Drosophila melanogaster (Diptera: Drosophilidae) and Lobesia botrana (Lepidoptera: Tortricidae)

Grape bunches dipped in avermectin solutions of 2 × 10-4, 1 × 10-3, and 5 × 103% (AI) resulted in 19, 59, and 87% adult mortality, respectively, of the vinegar fly Drosophila melanogaster (Meigen) held on treated grapes. In assays using an artificial diet to evaluate the effects on oviposition and adult development of D. melanogaster , avermectin B1 was much more potent than cypermethrin. A reduction of 95% adults was obtained at a concentration of 0.24 ng/cm2 avermectin compared with 60 ng/cm2 cypermethrin. A strong inhibition of oviposition and hatch was observed in the avermectin treatments. Developing stages of D. melanogaster were 5,000-fold more susceptible to avermectin B1 than adults. Assays with Lobesia botrana Schiffermuller, resulted in 98% mortality of larvae kept on grape bunches that had been dipped in a solution of 1030% (AI), and 56%mortality with 8 × 106% (AI) avermectin B1. This potency was higher than that obtained with cypermethrin. E. viteana adults were less susceptible to avermectin B1 than larvae.