The response of farmers' varieties and maize hybrids commonly grown in Lesotho was evaluated in field trials under natural infestations ofBusseola fusca(Fuller). Plant response of varieties and hybrids was evaluated in relation to a susceptible and resistant maize hybrid. The incidence of infested plants, number of damaged inter- nodes and number ofB. fuscaindividuals that successfully colonised plants of different varieties as well as yield loss was determined. All the local varieties and commercial hybrids were susceptible to damage byB. fuscaand sustained yield losses higher than that of the experimental resistant check hybrid. Maize varieties generally suffered lower yield losses than hybrids. Differences in yield losses between hybrids and farmers' varieties were ascribed to differences in length of growing season requirements (days to 50% flowering) and the incidence of damage to maize ears. Results indicate that Lesotho farmers can benefit from a stem borer resistance breeding programme and that adaptation of planting date can lead to escape of damage and reduced yield losses.