Comparison of efficacy of insecticides against cabbage aphids Brevicoryne brassicae

摘要

In five control experiments during 1987 and 1999 in the canton of Vaud and Valais (Switzerland), several insecticides were tested against cabbage aphids Brevicoryne brassicae on cabbage and cauliflower. Twenty active ingredients of different insecticide groups (organophosphates, carbamates, pyrethoids, fatty acids, triazinoids, thiocarbamates, cyanoamine and carbaryl-triazol) were applied when action thresholds were reached and efficacies were compared. When applied early in the season, the majorityof the insecticides had good efficacy. One or two treatments, timed by means of visual controls and corresponding action thresholds, were sufficient to protect the crop in most cases. Diaretiella rapae was the most common parasitoid of the cabbage aphid. Some insecticides protected the crop until harvest and spared beneficials. Syrphid larvae were efficient aphid predators. Due to lack of prey, they were less common in plots treated with selective aphicides than in untreated check plots.