Evaluation of Botanical Extracts Against Termites Infesting Tasar Food Plants

Abstract

Termites are gaining major pest status in tasar ecosystem in recent years and being observed in all the major tasar growing regions. Odontoterme sparvidens, Odontotermes obesus, Odontotermes proformosanus, Microtermes obesi (Hols), Coptotermes heimi (Wasm), Odontotermes latiguloides, Odontotermes ganpati, Odontotermes redemanni are the common species of termites damaging the tasar food plants. Therefore, an urgent need to develop certain ecofriendly management practices which are safe to silkworm. Hence, efforts have been made to evaluate the anti-termite activity of botanical extracts. In this study we have evaluated the toxicity of 6 different botanicals extracts against termites infesting tasar host plants. Bioassay results revealed that all botanicals extracted using n-hexane found effective including the solvent alone. Effectiveness of all the extracts might be due to toxic effect of n-hexane since it has been observed 100% mortality when n-Hexane used alone, whereas mortality in control was only 10%. Further extracts isolated using methanols were tested and in that also toxicity of methanol was evident (90%). Due to the toxic effects of n-hexane and methanol we have further isolated the selected botanicals using distilled water and conducted bioassay of these extracts against termites. Results indicated that among the tested botanicals lemongrass (93.00%), Vitex negundo (87.00%) and Eucalyptus (73.00%) found superior. Whereas other botanicals found less effective by recording lower per cent mortality. Hence outcome of the experiment suggests that these botanicals are having antitermite activity further they can be utilized for field application for effective and eco-friendly management of termites in tasar sericulture.