EVALUATION OF THE EFFICACY OF DELTAMETHRIN SPRAYING OR DUSTING ON RICE HUSKS AGAINST STORED PRODUCT PESTS IN THE GUANGDONG PROVINCE, CHINA

In South China where climate is hot and humid paddy stocks are infested by pests if they are not treated. No significant difference was observed in the efficacy of spraying and dusting on husk meal or whole rice husks. Deltamethrin applied at 0.5 ppm plus piperonyl butoxide at 5 ppm or at least 1 ppm when not synergised was found to be effective in protecting paddy. Fumigants and pirimiphos methyl provided protection only for 2 to 4 months because fumigants had no residual action and pirimiphos methyl at 10 and 15 ppm was not effective against Rhizopertha dominica (F.). The use of a plastic gas proof sheet delayed stored grain insect infestation for some months; Rhizopertha dominica (F.) were the first to reinfest paddy stocks. Deltamethrin and pirimiphos-methyl have complementary activity spectra, which leads to envisage associations in proportions which are to be defined.