INFLUENCE OF GRANARY TYPE AND FARM PRACTICES ON THE RELATIVE ABUNDANCE OF INSECTS IN GRANARY RESIDUES

The abundance of nine stored-product species found in crop residues in farm granaries in the Prairie Provinces was influenced by farm practices, kinds of crops stored in the granaries, and the materials used in the construction of the granaries. Some species were found more frequently than expected on farms where there had been previous infestations (Pyralis farinalis L.), or where there was livestock (Cryptolestes ferrugineus [Stephens]). Fewer samples than expected were found infested with Cryptophagus varus (W. & C.), where insecticidal sprays were used, but more C. ferrugineus than expected were found where fumigants or insecticidal sprays were used. Fewer samples of canola residues than expected contained insects, but barley residues contained more insects than expected. Wooden granaries contained more insects than expected, except for C. ferrugineus. Cole's coefficient of association showed that some species were often associated but other pairs of species such as Tribolium audax Halstead and Lathridius minutus L. were negatively associated. These relationships between species and their environments can be used to reduce the abundance of stored-products insects in farm granaries. © 1990, Entomological Society of Canada. All rights reserved.