Toxicity of three plant leaf extracts against larvae and pupae of melon fruit fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae)

Methanol extractives of leaves of three selected plants Azadirachta indica A. Juss., Persicaria hydropiper (Linn.) Spach and Vitex negundo Linn. were subjected to larvicidal and pupicidal test against the melon fruit fly, Bactrocera cucurbitae (Coq.) (Diptera: Tephritidae). In larvicidal test, offered the highest and lowest mortality has been calculated as 1.161 and 0.758 mgcm^-2 for A. indica; 0.853 and 0.275 mgcm^-2 for P. hydropiper; 2.213 and 0.732 mgcm^-2 for V. negundo after 6 hours and 24 hours of exposure respectively. In case of pupicidal test against melon fly, the highest and lowest activity has been observed for the extract of A. indica by LD50 0.26 mgcm^-2 and the extracts of P. hydropiper by LD₅₀ 8.70 mgcm^-2 respectively. Against B. cucurbitae, the pupicidal potentiality of leaf extractives of these three plants can be sequenced in a descending order as A. indica > V. negundo > P. hydropiper.