Varietal effects of cowpea, Vigna unguiculata, on tolerance to malathion in Callosobruchus maculatus (Coleoptera: Bruchidae)

► The varietal effect of cowpea on the response of C. maculatus to malathion was evaluated considering temperature and geographical strains of C. maculatus. ► Cowpea variety had profound impact on insecticide tolerance in C. maculatus. ► Interaction of cowpea variety-by-insecticide concentration had no significant effect on malathion tolerance in this bruchid. ► The predictability of changing C. maculatus susceptibility to malathion by altering one of the factors studied is very low.