Evaluation of Toxic Properties of Cotyledon Powders and Oils of Sandbox, Hura crepitans L. against Sitophilus zeamais Motschulsky (coleoptera: curculionidae)

Abstract

Hura crepitans cotyledons were extracted in the laboratorywith n-hexane. The powder and oil extracts were assessedat the temperature of 28±2o C and relative humidity of75±5 % for their insecticidal activity against Sitophiluszeamais infesting maize grains, using mortality, ovicidal,and adult emergence effect as indices. The long termprotectant ability of the powder and the oil was alsoinvestigated. Results obtained showed that powder andoil of H. crepitans were toxic on S. zeamais. The powdershowed 100 % mortality with dosage of 0.8 g by day 8 ofexposure, while the oil showed 100 % mortality withconcentration of 1.5 and 2.0 % by day 4 and 8 of exposure.The powder and oil extract drastically reducedoviposition and totally prevented adult emergence athigher powder dosages and oil concentrations. Both thepowder and oil drastically reduced infestation andsubsequent damage in treated grains. No damage wasrecorded in maize grains treated with 1.5 and 2.0 %powder and 1.0, 1.5 and 2.0 % oil of H. crepitans. Theresults obtained from this study showed that cotyledonspowder and extract from H. crepitans are effective incontrolling S. zeamais infesting maize grains in the storeand could serve as alternative to chemical insecticides.