Susceptibility of some cowpea, Vigna unguiculata (L.) walp, cultivars to cowpea seed beetle, Callosobruchus maculatus (Fab.), during storage

This study was undertaken to assess the susceptibility of cowpea cultivars (VITA -1, 84E - 1108, VITA - 4, LOCAL, 82E - 18, 820–699, TVx - 3236, and 82D - 716) to C. maculatus during storage. Results indicate variations among cultivars in mean % damage (8.9±1.9 – 78.8±3.3), mean developmental period (18.8±0.3 – 30.7±0.7 days), mean weight loss (3.1±0.5 – 20.4±1.5g), mean number of emerged adults (107.5±8.9 – 577.5±13.8) and index of susceptibility (6.7 – 14.5). A significant difference (P<0.05) existed among these means. Cultivars 82D - 716 recorded the highest mean developmental period, the least mean % damage, mean weight loss, numbers of emerged adults, and index of susceptibility. VITA - 1, 84E - 1108, and VITA - 4 were the most susceptible while the local cultivar was moderately susceptible by the end of the trials. There was a significant increase (P<0.01) in % moisture and protein content and a significant decrease (P<0.01) in viability in all the cultivars. The possible reasons for difference in susceptibility and the implications of these results in the choice of cultivars are discussed.