Contact toxicity of Canarium schweinfurthii Engl. tissues against Callosobruchus maculatus in stored bambara groundnut

The production of bambara groundnut is in the hands of peasant farmers and its improvement is militated by storage pests, such as Callosobruchus maculatus. Laboratory experiments were conducted on powders, extracts and oils of Canarium schweinfurthii for their insecticidal activity against C. maculatus in bambara groundnut. This was done at ambient conditions (30 – 350C and 70 – 80% r.h) between January 2011 to December 2011. Randomized completely block design in four replications was used. The results showed that contact toxicity of C. schweinfurthii tissues (cotyledon and mesocarp powder) caused 25 - 97% and 42.5 - 95% mortality, rerspectively, commercial prossed mesocarp oil caused 55 - 100% and laboratory processed cotyledon oil caused 62 - 100% mortality to C. maculatus. The highest mortality against C. maculatus were observed in methanol extract and petroleum ether of the mesocarp tissues which caused 80 - 100% and 90 – 100% mortality, respectively at the application rates of 1.25 and 2.5mg/ml/50g grain within 3 days post-treatment. In conclusion, C. schweinfurthii had insecticidal activities against C. maculatus using contact toxicity. The highest activities were observed in mesocarp and cotyledon tissues. These suggest that C. schweinfurthii can serve as alternative botanicals in protecting stored bambara groundnuts against C. maculatus.