The efficacy of pirimiphos methyl in crib storage of maize in South Western Nigeria

Pirimiphos methyl when sprayed at dosages of 10 and 15 p.p.m., effectively protects dehusked maize in cribs for 3 months against incipient or cross infestation by stored product insects. Longer storage would however require a reapplication of the insecticide. At 5 p.p.m., pirimiphos methyl is not a protectant against insect infestation of maize stored beyond 1 month. As insect numbers and grain damage increased, viability of infested maize decreased. Only when grain embryo is damaged or endosperm destroyed can insect infestation prevent grain germination.