Études toxicocinétiques et synergiques de l'azadirachtine dihydrogénée chez la pyrale du maïs, Ostrinia nubilalis.

Abstract

Toxicokinetic and synergistic studies were conducted with dihydro-azadirachtin (H$\sb2$-AZA) and a tritiated tracer on the European corn borer (ECB), Ostrinia nubilalis Huber. Azadirachtin, a triterpenoid extracted from the Neem Tree Azadirachta indica A. Juss, has been recognized for years for its antifeedant and growth regulation properties on different insect species. The results have shown that: (1) H$\sb2$-AZA reduces the growth and affects the development of the ECB; (2) the elimination of the tracer within the feces takes between 12 to 24 hours following an oral or topical treatment; (3) the gut, the carcass and the fat bodies are subject to the highest accumulation of tracer for an oral treatment; the gut and the carcass present the highest accumulation of tracer for a topical treatment; (4) the penetration of tracer in the cuticle takes place rapidly, within the first 12 hours after topical treatment; and (5) dillapiol and piperonyl butoxyde, two polysubstrate monooxygenase (PSMO) inhibitors, increase the toxicity of H$\sb2$-AZA for the ECB. This study contributes to the understanding of how O. nubilalis reacts to the introduction of a substance like azadirachtin within its body and of how this molecule acts on the insect.