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Drugstore Beetles

General Facts

Sometimes called the biscuit beetle, the drugstore beetle (Stegobium paniceum) is a stored-product insect pest found throughout Canada. It can be found in various commercial settings, including flour mills, bakeries, breakfast cereal manufacturing plants, confectionaries, distribution centres, retail stores, and residences. Drugstore beetles thoroughly damage stored and post-harvest grains and seeds, as well as packaged food products. They may also cause distress for home and business owners as they destroy food. The pests live in every Canadian province and commonly find shelter in heated structures to avoid the cold winters.

Appearance / Identification

image of drugstore beetles
Cylindrical in shape, the drugstore beetle is sometimes confused with the closely related and similar-looking cigarette beetle. While both types of beetles appear solid brown or reddish-brown in colour, certain distinguishing characteristics help separate the two species. The drugstore beetle possesses a pair of three-segmented club antennae and deep pits on the wing covers, which give the insect a striated appearance. Drugstore beetles also possess fine hairs running lengthwise along the wing covers. The stored-food pest measures up to 3.5 mm in length. See more pictures of drugstore beetles.


Although they prefer to live in warmer environments outdoors, drugstore beetles can survive just about anywhere heated shelter is available. Various commercial sites provide ideal conditions for the pests, including cereal and pet food manufacturing facilities, storage warehouses, and flour mills. The drugstore beetle is an expert flier and attracted to light, making home invasions both possible and likely.


Drugstore beetles eat a variety of different foods. While they cause the most damage to stored grains, seeds, and flour, the insects maintain a diverse and relatively indiscriminate diet that also includes pet foods, spices, books and manuscripts, leather, wool, hair, and even drugs, hence their common name. Known to even bore through wooden objects, the pests are capable of penetrating through tin, aluminium foil, and lead sheets, making stored foods virtually unprotected.

Life Cycle / Reproduction

Female drugstore beetles lay as many as 100 eggs or more at a time. The eggs are pearl white and difficult to see. They are deposited in a suitable food source and typically hatch after about 10 days. The newly hatched larvae are cream-coloured grubs shaped like the letter “C” and measure around 5 mm in length. After pupating for 12 to 18 days, immature drugstore beetles emerge as adults. The typical lifespan of an adult drugstore beetle ranges from 14 to 65 days.

Problems Caused by Drugstore Beetles

With such a varied diet and a propensity for infesting stored foods, the drugstore beetle causes multiple problems for both home and business owners throughout Canada. The presence of these insects often results in financial losses for food manufacturers and distributors as infested products are not fit for consumption and must be discarded. Because drugstore beetles also feed on inorganic materials, such as books, paper, and animal horns and antlers, they can damage or destroy displayed and stored artifacts and, in extreme instances, priceless museum pieces. Furthermore, the excrement and frass that drugstore beetles produce or leave behind may irritate the mouth, throat, and stomach if ingested.

Detection / Signs of Infestation

Drugstore beetle infestations may become noticeable in a variety of ways. First, the presence of dead adults or excrement remains a sure sign of infestation. The pests also produce pupation holes in stored foodstuffs and entry holes in food storage containers, though these holes may not be obvious. Additionally, visible evidence of larvae and larval cocoons persists as a definite sign of a drugstore beetle infestation.

Prevention Tips

Some of the best prevention methods for thwarting drugstore beetle infestations involve thorough sanitation and the proper storage of foodstuffs. Do not store exposed foods on shelves or in pantries; instead, place the edible items in containers made of a sturdy material, such as glass, and accompanied by tight-fitting lids. Regularly clean and vacuum shelves, bins, and storage areas to eliminate accumulating food particles. Rotating stock, refraining from mixing old and new products, and keeping storage areas dry also generally proves effective in preventing drugstore beetles from infesting.

Control / Removal

When food items show signs of infestation, heating small quantities at a time in an oven may successfully eliminate the insects. However, this method of drugstore beetle removal proves less than sanitary and may still render the infested food inedible. The selective use of appropriately labelled insecticides can be used to manage and control drugstore beetle infestations. For extreme cases of drugstore beetle infestations, contacting a professional pest control specialist is often the best course of action to take.

Get Rid of Drugstore Beetles
Pictures of drugstore beetles