INSECTS IN STORED CEREALS, AND THEIR ASSOCIATION WITH FARMING PRACTICES IN SOUTHERN MANITOBA

One or more insects were captured during 1 week in probe traps placed in granaries holding wheat, barley, or oats in 51% (n = 116) of grain bulks in the fall of 1986, 88% (n = 111) in the summer of 1987, and 85% (n = 106) in the fall of 1987. Fungivorous insects were the most common and predominant group at all sampling times. Granivorous species were the rusty grain beetle, Cryptolestes ferrugineus (Stephens), and the red flour beetle, Tribolium castaneum (Herbst). Grain in galvanized steel and wooden granaries was usually infested with insects to the same extent; granaries with or without aeration systems usually contained the same number of species; small bulks of grain often were infested less frequently than large bulks; the presence of livestock feed on farms did not result in greater insect incidence; and insecticide use in granaries did not prevent re-infestation of grain and insecticide use increased from 24% in 1986 to 31% in the fall of 1987. The kinds of insects detected in grain stored with various farming practices, and co-occurrence with other arthropods in the grain provides baseline information on potentially changing patterns of infestation.