Flour beetle is a very common commercial pest infesting a variety of grains and food material. The rust-red or flour beetle is frequently found in stored products in the USA Extremely important pest of flour but can infest a variety of food-stuffs. In large numbers can cause flour to turn grayish in color and mould more quickly. It can leave a disagreeable taste and odor in flour because of secretions from scent glands. The rust red flour beetle is worldwide and most destructive pest of stored products and is cosmopolitan in distribution. It is the most common pest of wheat flour. It also causes serious damage upon dried fruits, pulses and prepared cereal foods, such as cornflake, pasta, biscuit, beans, nuts, etc. It is an often the most common species in the pest complex attacking stored wheat although its pest status is considered to be secondary, requiring prior infestation by an internal feeder.
Flour beetle are more common in cool, temperate regions. The flour beetle is 3-4 mm in length the larvae are about 6 mm long. The adult is red-brown in color and the larvae are a light honey color and about. It resembles the rust-red flour beetle, except for the antennae which is four segmented and gradually thickens towards the tip - another slight difference is in the shape of the thorax. The sides of the rust-red flour beetle are curved, whereas the thorax of the confused flour beetle is straighter. It has well developed wings but seldom flies.
Female lay between 400 - 500 eggs, with peak oviposition occurring during the first week. Adults may live longer than 3 years, and females may lay eggs for more than a year. Eggs are deposited directly in flour, other food material, or attached to the surface of the container. They are white or colorless and covered by a sticky material to which flour can adhere. Eggs hatch in 3 - 5 days at 90-95°F. Larvae burrow into kernels of grain but may leave their burrows in search of a more favorable food.
They have been reported in grain, flour, and other cereal products, beans, cacao, cottonseed, shelled nuts, dried fruit, dried vegetables, drugs, spices, chocolate, dried milk and animal hides. They cannot feed on whole grain, but can feed on broken kernels that are usually present. Beetles move quickly and are strong flyers. Preferred habit is around storage areas with poor hygiene, broken grain, gradings or bulk cottonseed In general, fungi may play a significant role in the nutrition of rust-red flour beetles.