Evaluation of Combretum imberbe wood ash for control of Oryzaephilus surinamensis (Linn) on stored food commodities in Botswana

Abstract

The effectiveness of C. imberbe wood ash against O. surinamensis on crushed or ground food commodities was investigated in the Entomology laboratory, University of Botswana. The treatments were applied at three dosages (1, 3 and 5 g/50g). Probit analysis was used to determine the LD50 values for the treatments. The results showed that C. imberbe wood ash was relatively more effective on broken than on ground maize; better on ground than on broken sorghum; and on broken than on ground rice. The type of food commodity, whether broken or ground, did not have a significant effect on the effectiveness of C. imberbe wood ash when applied to cereal commodities. When applied to pulses, C. imberbe wood ash performed better on broken than on ground Bambara groundnut; on broken than on ground cowpeas; and on broken than on ground beans. The type of food product had a significant effect on the effectiveness of C. imberbe when applied to pulses. The study shows that C. imberbe can be a valuable component of integrated O. surinamensis management programme for farmers in Botswana. The results are discussed in the context of sustainable harvesting of the plant by resource poor farmers.