Every summer, I get calls from folks wondering why there are nearly microscopic bugs covering the walls and floors of their feed storage areas and their feed buckets. Looking for a cause, many easily trace it back to their bags of grain. The dust on the exterior of the affected bags appears as if it's moving in a gentle breeze, and there may be a thick layer of dust coating the inside of the feed bags. On closer inspection, it's apparent that the dust is actually hundreds of thousands of nearly microscopic grey-brown looking mites. These are grain mites.