The efficacy of insecticides against Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (Fab.) (Coleoptera: Bostrichidae) exposed to treated stored rice (Oryza sativa) was tested. The insecticides were applied using a propelling air atomizer (5 ml of mixture/kg of rice); for the control only water was used. For each treatment 1.2 kg of stored rice, were treated in plastic bags and stored in raffia bags in a climatized room (25 ± 2ºC). Fifteen days after treatment, 200 g of the treated rice, from each treatment, were infested with 40 adults of each species. This procedure was repeated every 30 days. The number of dead insects was recorded 15 days after infestations, at 30, 60, 90, 120, 150 and 180 days after the insecticide application. Sumigran plus (15 and 20 ml/t) was effective against S. oryzae until 180 days after treatment. Sumigran plus (15 and 20 ml/t), Sumigran ® + Sumidan ® (15 + 15 and 20 + 20 ml/t), Sumigran ® + K-Obiol ® (15 + 15 ml/t), were effective against R. dominica up to 180 days after treatment.
Insecta; chemical control; stored-product pests
