Canada has a reputation around the world for high quality grain. To maintain this high standard of quality, Canada sells its grain with an assurance that it is free of grain-feeding insects. Given the correct conditions, insect populations can increase rapidly, decreasing the quantity of grain, reducing the quality and in extreme cases causing "hot spots", moist pockets of heating grain (White, 2001).
There are four types of insects that you can find in stored grain.
Download the PDF file for the full paper from the Agronomy Update 2008 conference proceedings