MORTALITY OF ADULT GRAIN BEETLES IN SAMPLE DELIVERY SYSTEMS USED IN TERMINAL GRAIN ELEVATORS

Abstract

AbstractThe detection of insect infestation by the Canadian Grain Commission is decreased in efficiency by the mortality of adult beetles in the pneumatic sample delivery systems used in terminal elevators in the Vancouver, B.C., area. Dead insects are difficult to see while grading the grain and cannot be extracted by Berlese funnels.The level of mortality varied with the species of beetle and the system tested, but not with the type of grain. In one system the following mortalities were found: Cryptolestes ferrugineus (Stephens), 73%; Oryzaephilus surinamensis (L.), 65%; Tribolium castaneum (Herbst), 65%; and Sitophilus granarius (L.), 22%. C. ferrugineus, the most important insect infesting Canadian grain, sustained an average mortality of 55% in the five systems tested. No consistent mortality pattern was found among the systems with respect to delivery tube length, number of turns, or approximate grain speed. Berlese funnel extraction was found to be inefficient for O. surinamensis and inconsistent for S. granarius.