Toxicite de fongicides commerciaux vis‐a‐vis des larves de Drosophila mekmogaster Meigen (Diptera, Drosophi Udae) et incidence sur la sex ratio

Abstract

Bouillie bordelaise^®, Benlate^® , Euparene and Dithane^® M₄₅ had no effects on Drosophila eggs. However, a post‐hatching mortality was observed and, in all cases, a “dose effect” was established. There was a quick effect with Bouillie bordelaise, a slow and continued one with Benlate and Euparene, and the effect was delayed until the pupal stage with Dithane. Bouillie bordelaise, Benlate and Euparene slowed down the larval development and the emergence period was longer, according to the doses. Bouillie bordelaise was always the most toxic fungicide and Dithane the least one. The sex‐ratio was not disturbed with Bouillie bordelaise. With Benlate and Euparène, the females were more sensitive than the males, while Dithane was more toxic towards males. Considering a same fungicide, a difference was exhibited according to the chosen criterion: Benlate caused an effect on larval mortality which was more important than its effect on the developing‐time. Moreover, both carbamates, Benlate and Dithane, acted differently whatever their toxicity level.

Mots clés:

• fongicides
• insecte
• mortalité larvaire et nymphale
• durée du developpement