Figure 7. An infestation of Indianmeal moth, Plodia interpunctella (Hübner), in a jar of pistachio nuts. It was later determined by the senior author that the nuts were purchased from a commercial supermarket that had an infestation in a bin of bulk foods. One or more infested nuts was brought home. The lid of the jar was slightly loose allowing several generations of Indianmeal moths to reproduce, and eventually allowing larvae and adults to escape to pupate and spread the infestation. If the jar had been tightly closed the infestation would have died, either from lack of air or from a buildup of moisture that would have allowed the development of fungus to destroy the larvae and adults . Observe the frass, insect fecal waste, on the outside of the nuts, as well as the webbed pupal cases in the center of the photograph. A few adults are also visible.
Credit: Lyle Buss, University of Florida