Indianmeal moth

Indianmeal moth (Plodia interpunctella). Adults have a 14–20 mm wingspan and a 6–7 mm body length. Forewings are distinctly bicolored: the basal third (near the body) is cream to yellow, while the apical two thirds are coppery red to dark gray, creating a sharp transverse contrast; forewing length up to 10 mm. Larvae (caterpillars) are whitish, sometimes with a greenish or pinkish hue depending on diet, and bear a brown head capsule; they reach 8–10 mm at maturity, occasionally up to 17 mm. They are distinguished from Ephestia larvae by the absence of black pinacula at the bases of the setae.

This pest is a classic secondary pest of stored cereals. Damage is caused solely by the larval stages, which are external feeders on cracked kernels, broken grain, and milled fractions; sound, intact kernels are not penetrated. As larvae feed they spin abundant silk, producing dense webbing that binds particles into clumps, blankets the commodity surface, and contaminates lots with frass. These silk mats impede product flow and can obstruct milling equipment, clogging systems and disrupting operations. Beyond cereals, infestations also involve dried fruits, nuts, cocoa products, chocolate, herbal goods, and seeds, increasing the risk of cross-contamination. The result is caking and downgraded quality, with added cleaning and downtime costs.

Indianmeal moth, Plodia interpunctella (Hübner), is recognized in stored grain by the following infestation signs: - Silken webbing: larval silk forming sheets and feeding galleries that bind kernels and can mat the grain surface. - Larval frass: fecal pellets and fine debris intermixed with kernels and webbing. - Cast exuviae: shed larval skins and empty pupal cases (nymphal exuviae) left within the commodity or on nearby surfaces. - Adult remains: fragmented moth bodies, detached wing scales, legs, or antennae among the product. These indicators, especially conspicuous silk webbing with frass and cast skins, reliably signal the presence of P. interpunctella in stored grain.

Indianmeal moth (Plodia interpunctella) breeds on stored goods. Females oviposit directly on the commodity; the adhesive eggs stick to kernels. One female lays up to 300 eggs. Neonate larvae feed and spin abundant silk webbing. At the end of larval development, larvae leave the infested product and climb walls or equipment to pupate in a protective silken cocoon on the surface or very near the food. Adults emerge, mate, and resume oviposition. Development is temperature-dependent, taking roughly 2–6 months. Larvae overwinter in unheated sites; in heated buildings, generations continue year-round.

Plodia interpunctella is a synanthropic stored-product pest that thrives in granaries, stores, silos, warehouses, food-processing and distribution plants, and household pantries, in dry, food-rich microhabitats where larvae infest stored cereals and packaged foods.

Almond moth (Cadra cautella) Mediterranean flour moth (Ephestia kuehniella)