Insecticidal activity of selected botanicals on Sitophillus zeamays L. in stored maize grains

Abstract

Laboratory studies were conducted to study the effect of five leaf powders (10%) of Lantana camera, Azadiracta indica (Neem), Annona squamosa (Annona), Justicia adhatota (Adathodai) and Ocimum tenuiflorum (Tulsi) against maize weevil, Sitophilus zeamays L. (Colepotera: Curculionidae) infesting maize grains in storage. Among them, O. tenuiflorum was found to be significantly the best treatment. O. tenuiflorum and A. squamosa killed 86% of adult weevils by about sixth week. Significant differences were found between the numbers of emerged weevils in different treatments. The new births were not observed in the grains treated with chemical pesticide Actalic, O. tenuiflorum and A. squamosal. But the appearance of new insects was detected in L. camera, A. indica and J. adhatota from sixth week and it was higher in L. camera compared to the A. indica and J. adhatota from 6th week onwards. The effectiveness of O. tenuiflorum and A. squamosa in the control of maize storage weevil was apparently as efficient as the chemical pesticide Actalic. Use of these botanicals may prevent environmental pollution and replace chemical pesticides currently being used by most farmers and also in agro industries where grains are usually stored in bulk several months to manufacture feeds for human and livestock.