Comparative study on insecticidal activity of Jatropha curcas oil, seed cake and seed cake extracts against Anoplolepis gracilipes

The invasive yellow crazy ant, Anoplolepis gracilipes is commonly found in gardens and forests of tropical and subtropical locations. These ants are a problematic pest in both urban and rural environment because of their extreme foraging behavior. The control of these insect pests is by using synthetic pesticides. The use of plant derived compounds is now gaining importance, as they are found to be safe to the environment. The use of non-edible oil seeds of Jatropha curcas containing phorbol esters has been considered as a potential source of biopesticide. The present study evaluates the potential insecticidal activity of Jatropha seed oil and extracts from seed cake on A. gracilipes. The Jatropha seed oil (25, 50 and 100%), Jatropha seed cake (2, 4 and 6 g), Jatropha seed cake cold water extract and hot water extract (5, 10 and 20%) were evaluated for insecticidal activity by studying the mortality rates of the adult workers of A. gracilipes. The bioassay studies indicated that, 100% mortality was observed using Jatropha seed oil at 50 and 100% concentrations. The hot water and cold water extracts of Jatropha seed cake at 5, 10 and 20% levels exhibited increase in mortality with increasing concentrations and exposures. However, the ants were susceptible to the hot water extract than the cold water seed cake extract after 9 h exposure.