Comparative use of botanical oil extracts in pest management

The efficacy of three botanicals, Cymbopogon citrates, Hyptis suaveolens and Eucalyptus globulus were tested on Callosobruchus maculatus (F), a pest of cowpea under ambient laboratory conditions. Oil extracts were obtained using soxhlet apparatus and petroleum ether as solvent. Efficacies of the extracted oils were determined on counted Callosobruchus maculatus and cowpea seeds in petri dishes. Insect mortality was observed at the different concentration levels for a few minutes and repeated three times for three weeks. In a screen house experiment, 1.0% concentration was observed to be the average and most effective concentration and subsequently selected as a basis for comparison in all the selected botanicals. The application of Hyptis suaveolens at 1.0 % was observed to be the most effective and significantly different from other botanicals while Eucalyptus globulus was the least effective.