This insect, which is one of the most common stored product pests in Kentucky kitchens, occurs throughout the world. It is a secondary pest that can infest all kinds of flours, meals, processed foods, dried fruits, and worst of all, chocholate. The larvae (caterpillars) produce a tremendous amount of silk webbing that masses the infested product together. They have done that in the grain mass in the picture.
The female moth lays up to 400 eggs singly or in small batches on food products. The small larvae disperse and begin to feed and spin tubes in crevices within the commodity. The larval stage can take as little as 13 days to over 280 days, depending upon the temperature. Full grown caterpillars, which are a pale pink to white, crawl away from the infestation site and pupate in a silken cocoon.
The adults are distivelt marked moths that can be seen flying around or crawling over the grain surface. The base of the front wing is light tan, the rest is a red to coppery brown. This is a good character for recognizing the adult. A diamond-shaped commercial pheromone can be used to monitor for males and to detect infestations in storage areas.