Adult confused flour beetles reach about 1/8 inch long.
These beetles have an elongated body with parallel sides. They are reddish in color and flattened top to bottom. Larvae are elongate, shiny, and wormlike in appearance.
The confused flour beetle cannot fly despite its fully developed wings. These beetles commonly infest flour mills, warehouses, and grocery stores and are the most abundant and injurious insect pest of flour mills in the United States.
The confused flour beetle is a scavenger that feeds on a variety of food products including grain, beans, dried fruits, nuts, chocolate, and other foods. They are unable to feed on whole, undamaged grains. They are often found along with weevils because weevils bore into grains and the confused flour beetle can then feed on the opened grain. When these beetles are present in great numbers they cause flour products to turn gray and quickly develop mold. Flour and meal products are especially prone to infestation.
Females lay an average of about 450 small, clear white eggs, which are loosely laid on fine materials and broken kernels. The eggs are covered with a sticky secretion, which the fine material adheres to. The mature larva is brownish-white and has six legs. The life cycle takes about one to four months.
The adult beetles are very active and move about rapidly when disturbed. The beetles do cause damage by feeding but cause more problems by contaminating grain. Large numbers of dead bodies, cast skins, and fecal pellets, as well as liquids can produce extremely pungent odors which can result in poor feed consumption by livestock and rejection by grain buyers.
With any stored food pest, the source must be eliminated before control can be obtained.