Many different kinds of insects, mostly small beetles and moths, infest food and nonfood products of plant and animal origin commonly found in urban environments. Collectively, this group of insects is called stored product pests. For homeowners, often the first sign of a stored product pest infestation is the sudden, unexplained and then persistent presence of numerous insects in a particular area of the home. If food is not limited, populations of stored product pests can multiply rapidly and become widespread and sustained. This lesson discusses the identification and control of several of the most common species of stored product pests.
The life cycle of stored product beetle and moth pests includes an egg stage, several larval stages, a pupal stage and finally an adult stage. Adults often mate soon after emergence and then immediately begin searching for a food source. During their lifetime, females lay approximately 100 to 1,000 eggs, depending upon the species. After deposition, eggs incubate for days to weeks. Following egg hatch, larvae develop through a series of life stages called instars while infesting and consuming their food resource (discussed below), where they remain mostly unseen. Each successive instar is larger in size and consumes greater amounts of food than the previous instar. Larval development requires weeks to a month or more to complete. The last larval instar pupates, and an adult emerges a short time later. Under optimum conditions, such as warm temperatures and high humidity, most stored product pests can complete a life cycle in just four to five weeks.
For most species of stored product pests, there are multiple generations per year. In some species of stored product pests, only the larval stages consume food. In these cases, the sole purpose of the adult insect is to mate, discover a food resource, and deposit its eggs within the few days or weeks the insect remains alive. Insect species in which the adults also feed can be long-lived, survive and continue to infest and feed on susceptible foods for several months to a year.