CONTROL OF INSECTS IN BAGGED GRAIN BY INJECTION OF DICHLORVOS

Dichlorvos has been distributed through the intergranular spaces of bagged wheat and barley to control Oryzaephilus surinamensis (L.) and Sitophilus granarius (L.). The insecticide was dissolved in carbon tetrachloride and sprayed into the air stream passing from a motorized knapsack sprayer to a perforated lance which was pushed into the grain. Good distribution of insecticide and a high control of breeding insects was obtained. Dichlorvos residues were higher on wheat than on barley and greatest in places where dust and frass had accumulated. When dichlorvos was injected at the rate of 20 ppm the highest residue found after 1 day was 30 ppm on a dusty pocket of wheat and this had fallen to 5·3 ppm after 6 days. © 1968.