Evaluation of Ethyl Acetate Extract of Some Botanicals against Rice Weevil Sitophilus oryzae L. (Coleoptera: Curculionidae) in Stored Maize

Abstract

In the present study, botanicals (11 nos.) were extracted using ethyl acetate solvent (mid-polar) and evaluated for their fumigant toxicity and repellent activity at 5% concentration against rice weevil, Sitophilus oryzae L. in comparison with Acorus calamus.The results revealed that all the botanicals were effective against Sitophilus oryzae compared to untreated control. Mentha spicata 5% ethyl acetate extract exhibited 83.33% fumigant toxicity after 72 hours of treatment with maximum repellency rate of 76.11%. Ocimum sanctum displayed 80.00% fumigant toxicity with the repellency rate of 76.11% and grouped under Class IV. Vitex negundo 5% treatment caused 83.33% fumigant toxicity, and it was statistically on par with the M. spicata and the repellency rate was 72.78 against S. oryzae. Curcuma longa caused effective repellency rate of 75.56% and was grouped under Class IV. Hence, it is concluded that 5% ethyl acetate extract of M. spicata, V. negundo and O.sanctum were toxic against S. oryzae in stored maize.