A Comparative Study on the Efficacy of Two Lamiaceae Plants on Egg - Laying Performance by the Pulse Beetle Callosobruchus Chinensis Linn. (Coleoptera : Bruchidae)

Abstract

The pulse beetle Callosobruchus chinensis Linn. (Coleoptera:Bruchidae) is one of the major pests of pulses in storage. During the present study an attempt was made to screen and compare the efficacy of Ocimum sanctum and Ocimum basilicum (Lamiaceae) on egg-laying performance of the bruchid on grains of Vigna radiata (mung). The leaves of the select two plants were employed in the form of crude extract, powder suspension, aqueous extract, ethanol extract and diethyl ether extract at dose concentrations of 10, 25 and 50%. Significant reduction (P< 0.05) in oviposition was documented in sets treated with the formulations of both the plants as compared to control and normal. The formulations of O. basilicum were observed to be superior to O. sanctum in reducing egg-laying. Moreover, ethanol extract, crude extract and powder suspension were also noted to significantly bring down the number of eggs laid by the pulse beetle. Dose concentration was found to be inversely proportional to the number of eggs laid by the bruchid and formulations of 50% concentration resulted in minimum oviposition. The results suggest that formulations of both the species of Ocimum have a potential to act as ovipositional deterrent and can beemployed against C.chinensis for its control.