Antifeedant and contact repellent activity of thyme, tarragon, marigold and lavender crude extracts against Epicauta atomaria (Coleoptera: Meloidae)

Abstract

Antifeedant and contact repellent activity of thyme, tarragon, marigold and lavender crude extracts against the insect pest Epicauta atomaria Germar, 1821 (Coleoptera: Meloidae) was evaluated. The extracts were obtained by sequential maceration with dichloromethane, ethyl acetate and methanol. The antifeedant and contact repellent activity was evaluated by means of the feeding index and repellency percentage respectively. The results obtained indicate that the tarragon dichloromethane, ethyl acetate, and methanol extracts, lavender methanol extract and marigold and thyme ethyl acetate extracts, had a strong antifeedant activity against E. atomaria, both with median AI values of 100%. On the other hand, only the lavender dichloromethane extract had a moderate repellent activity against E. atomaria, at all the exposure times evaluated, with median repellency percentage values of 60%, 80% and 50% at 15, 30 and 60 minutes of exposure, respectively.