An investigation of the extent of infestation of stored maize by insect pests in Rungwe District, Tanzania

Two hundred and sixty randomly selected subsistence farm households in Katumba ward, Rungwe District, Tanzania, were interviewed regarding methods that they use to prevent or control insect pests in stored maize. Maize samples were randomly collected from 130 out of 260 farm households and studied for infestation by insect pests, using incubation and inspection methods. About 93 % of the maize samples were found to be infested, either by weevils only (specifically Sitophilus zeamais and S. oryzae), by moths only (specifically Sitotroga cerealella), or by both weevils and moths. Both indigenous and improved varieties of maize were infested by the insect pests. The insect population density ranged from 0 to 210 per 120 maize kernels (or 51 g of maize), with an average of 80 insects per 120 maize kernels and a standard deviation of 51.44, amounting to 1,555 insects per kg of maize. Methods that farm households used to control the infestation of stored maize by insect pests were found to be inadequate. It was concluded that, with such high levels of infestation by insect pests, vulnerability of the subsistence farm households to food insecurity was inevitable. It was recommended that the government of Tanzania should make efforts to improve the resistance of maize grown in Rungwe district to Sitophilus and Sitotroga cerealella species, and that the affected farm households be encouraged to embrace new technologies, including genetic improvement of the resistance of maize to pests.