Grain infested by the angoumois grain moth larvae has an unpleasant smell, and is less attractive for consumption. Most problems with the angoumois grain moth in corn occur in crib-stored ears, although the infestation may have begun in the field. Corn infested in the field may harbor larvae feeding within corn kernels. When the newly harvested, infested corn is cribbed, the larvae continue to develop, pupate, and emerge as adults, which in turn deposit eggs on uninfested kernels. Several generations of the insect can be completed during prolonged warm falls, resulting in a large portion of the grain being damaged.
Female moths deposit eggs on grain kernels throughout the crib.
Under normal conditions, a female will lay forty eggs. The eggs are glued to the kernel. Larvae emerging from the eggs eat through the kernel and begin feeding on the endosperm or germ. To assist in penetrating the kernel, larvae sometimes spin a cocoon that they use for leverage. Once inside the kernel, larvae continue to feed until mature, enlarging a cavity within the kernel.