THE MERCHANT GRAIN BEETLE, ORYZAEPHILUS MERCATOR (SILVANIDAE: COLEOPTERA), AS A HOUSEHOLD PEST IN CANADA

Abstract
A 34-question interview relating to the occurrence, distribution, and economic importance of the merchant grain beetle was administered to a random sample of 2341 dwellings in Winnipeg in 1971 and 1152 dwellings in 1980. The results showed that a higher percentage of apartments and other multiple dwellings were infested by this insect than were houses. Using the Winnipeg survey figure, we estimate that the total cost of infestation in Canadian residences was $2.9 million in 1971 and $6 million in 1980. These figures do not include the costs of commercial pest control services. Oatmeal and flour were infested most frequently in 1971 with mixed cereal most frequent in 1980. After food, the next most frequent sources of beetles in kitchens were cupboard shelves and breadboards. Most people who found beetles in a food product discarded the infested product and adjacent foods whether or not they were infested. The results of the surveys suggest that the merchant grain beetle is a widespread and economically important household pest in Canada, particularly in apartments where is it a chronic problem.