The problems with insects in commercial and farm-stored corn, small grains, dry beans, and soybeans are reduced to a minimum by Michigan's cool climate and usually short period of storage (Ruppel, 1976). Yet insects still infest scattered bins of grain in the state. The incidence of stored grain problems has increased over the past few years. This increase is attributed to an increase in farm storage, often under poor conditions. Poor ventilation of the grains that causes an increase in moisture content at the surface of the grains has been the most common problem. The result has been a flush of problems with what are considered secondary pests; that is, those species that usually can increase only in grains that are in poor condition.
Ruppel, Robert F.
"An Inventory of Stored Grain Insects in Michigan,"
The Great Lakes Entomologist: Vol. 10
, Article 13.
Available at: http://scholar.valpo.edu/tgle/vol10/iss4/13