Warehouse Beetles

Warehouse Beetles are a small round beetle which will prosper in pantries, closets and warehouses where wheat grain, cereal and other food is stored. Easily mistaken for other small beetles, this persistent pantry pest was first discovered in the United States sometime around the Second World War.

Though found to infest warehouses and food processing plants, Warehouse beetles can infest any structure which harbors the food they like. Warehouse beetles are small, about 1/8″ long, and they appear to be oval shaped with a dark colored pattern upon their back. These colors can include yellow and brown and many shades thereof which are present on their wings.

Larva will feed on just about anything though they prefer wheat, barley or rice. Other common food includes dried blood, milk, pollen and dead insects. Larvae begin to feed as soon as they find food and will do so for about a month. They will then pupate into adults, which takes another couple of weeks and then spend a week or so as an adult mating and laying eggs. Though this whole cycle can take about two months to run its course, it’s not unusual for it to take 3-4 months. The exact time span seems to be dependent on food supply, humidity and temperature. One thing is for sure, they are very hardy as either larva or adults.

Warehouses or grain processing plants which have activity will have to monitor hot points and identify just where the beetle is most active. Once identified, treatments will have to be regular and become part of their overall active integrated pest management program. Without monitoring, Warehouse Beetles will soon multiply and become wide spread throughout the structure.

Residential homes which have activity are not faced with nearly the amount of treatment needed or potential for large infestations like processing or storage buildings. Most homes have enough food to harbor a small breakout but not nearly enough to allow the beetle to get out of control.

Warehouse Beetles feed on cereals, candy, cocoa, cookies, cornmeal, fish meal, pet foods, flour, nuts, dried peas, beans, pasta, potato chips, spices, dead animals and dead insects. Ingesting infested food that contains the molted skins of the larvae can cause intestinal irritation.