Entomotoxic Effect of Five Varieties of Bambara Groundnut (Vigna subterranea) and a Variety of Red Bean (Phaseolus vulgaris) against Old Larvae and Adults of Tribolium castaneum Herbst (Coleoptera, Tenebrionidae)

Abstract

The entomotoxic effect of five varieties of Bambara groundnut (McFoSc, BlRSc, BlRAcV, MnRSc, and BnRaSc) and one variety of common bean flours (GGR) is evaluated on old larvae and adults of Tribolium castaneum (Coleoptera, Tenebrionidae) under laboratory conditions with ambient temperatures ranging from 32°C to 36°C. This study aims to mitigate the damage caused by Tribolium castaneum to stored grains and legumes. The flour from each variety was obtained by grinding and sieving. A total of 150g of each flour sample was infested with either 20 old larvae or 20 newly emerged Tribolium castaneum. The variables observed included mortality rates of old larvae and adults, the number of F1 progeny, and the number of larvae, nymphs, and adults in the first generation. The flour of red millet (MR) which is a cereal was considered as control. After introducing the adults into the flours of different varieties, no mortality was observed for the ML, MCFOSC, MNRSC, BNRASC, and GGR varieties within 24 hours. The mortality rates were 1.25 ± 0.96 and 5 ± 0.72 for the BIRSC and BIRACV varieties, respectively. After four weeks of treatment, the cumulative mortality rates for the larvae were 93.75% for the GGR variety, 66.25% for the BIRACV variety, 56.25% for the MCFOSC variety, 55% for the BIRSC variety, 37.5% for the MNRSC variety, 31.25% for the BNRASC variety, and only 5% for the control (MR). The flours of these leguminous crops have a negative impact on the development of Tribolium castaneum by prolonging the duration of larval development. It suggests that these different leguminous seed varieties can be effective in controlling insects during storage.