| Abstract: | The solvent extracts of four plants, viz. Polyalthia longifolia (Sonn.) Thw. (PL), Paederia foetida (PF), Limonia acidissima L. (LA) and Balanites aegyptiaca (L.) Del. (BA), from different families, were screened for their antifeedant, insecticidal and insect growth regulatory potential against important crop pests. The solvent extracts, namely methanol, petroleum ether, chloroform and water, of all four plants were tested for their bio-activity against lepidopteran insect pest, Spodoptera litura; and sucking insect pest, L. erysimi (mustard aphid). It was observed that Polyalthia longifolia (methanol extract) exhibited maximum potency with least concentration of 0.1 % (~1080 ppm) to give 50 % antifeedancy, followed by P. longifolia (petroleum ether) with a value of 0.2 % (~2360 ppm) and Limonia acidissima (methanol) and L. acidissima (petroleum ether). The least active compound for antifeedancy was found in the aqueous extract of Balanites aegyptica. Out of 16 plant extracts bio-assayed, methanol showed potential antifeedancy when compared with chloroform, water and petroleum ether extracts. But chloroform and petroleum ether extracts of all four plants gave very promising insecticidal activity against aphids, in comparison to other two extracts. L. acidissima (water), B. aegyptica (methanol), P. longifolia (methanol) and P. foetida (water) did not give any insecticidal activity with 50 % lethal concentration (LC50) up to 0.1 % as maximum concentration. |
