Seasonal Activity of Stored-Product Insects in and Around Farm-Stored Wheat

This study was conducted to examine the activity of stored-product insect pests outside farm storage facilities during the first 2 mo of storage and to relate that activity to colonization of the grain by insects. Environmental parameters describing the grain storage environment also were analyzed to help in explaining the relationship between insect densities inside and outside grain bins. The most abundant species collected were Ahasverus advena (Waltl), Tyhaea stercorea (L.), Rhyzopertha dominica (F.), and Cryptolestes spp. Farms with high numbers of stored-product insects outside of storage facilities had high numbers of insects in 25-bu experimental bins, and farms on which few insects were detected outside also had fewer insects in 25-bu bins. However, this relationship was not true for commercial farm bins, possibly because of the use of insecticide on the grain or residual pest populations in farm bins. Grain moisture and test weight and the presence of livestock tended to affect insect numbers in the untreated experimental bins, but the effects were not always consistent among species. In farm bins, the use of protectants on the grain tended to obscure expected relationships to environmental parameters.