Published online by Cambridge University Press: 31 May 2012
Over 5,000 cargoes of grain, grain products, oilseeds, oilseed products and pulses from Canada were examined between 1953 and 1959. Only a few cargoes were found to be infested and there was a general decline in infestation over this period. Many of the insects recorded were acquired from the structure of the ships but mites were more frequently introduced with the grain. The miles which occurred most frequently were Acarus sira, Glycyphagus spp. and Cheyletus spp.; the commonest insects were Psoeopreri and Cryptolestes spp. Including those species derived from residues in ships, the total of species and species groups recorded was 77. Cases where insects have been derived from infested residues in the ships are described. A greater variety of species is to be found on Western Canadian, than on Eastern Canadian grain. This appears to foe due to the damp conditions brought about by overstowage of the grain with lumber and the consequent high proportion of mycetophagous species. The incidence of most grain-infesting insects and mites declined steadily during the examination period