Tribolium confusum and Tribolium castaneum are two beetle species that are known to infest stored food within grocery stores, kitchen cabinets and pantry shelves. These two species are more commonly known as “confused flour beetles,” and “red flour beetles,” respectively, and are both nearly identical in appearance. Along with “sawtoothed grain beetles,” and “indian meal moths,” confused and red flour beetles are the most economically significant insect pests of stored food products within homes. Some insect pests of stored food products mainly infest warehouses and factories, but many species are problematic within residential homes. This latter group of pests are known as “pantry pests,” and they often contaminate the food items they infest.

Red and confused flour beetles often co-occur in homes because they inhabit the same environments where they compete for the same resources. Adults of both of these species are small, possess antennae, are reddish-brown, and around 3 ½ mm in body length. The red flour beetle has a three-segmented antennae, with the last bulbous segment being noticeably larger than the three leading back to the head. The confused flour beetle, on the other hand, has a four segmented antennae, with each bulbous segment becoming slightly larger as they progress away from the head. Both of these species mainly feed on grains but they will infest peas, beans, shelled nuts, dried fruits, spices, chocolate, and peppers.

Adult flour beetle females deposit five to eight eggs per day on food products within infested homes, and while this may not seem like many, females lay eggs every day for their relatively long two year lifespan. The larvae, or “grubs” are worm-like, legless, white to light brown in color, and between 4 to 7 mm in length. Larvae are difficult to notice within infested foods because they climb into the center of grain kernels where they cannot be readily seen, but infested products normally smell foul with a grey discoloration. The first step in eliminating flour beetle infestations is to throw out all infested food items, followed by a deep cleaning of the area where the infested items were stored. Larvae and adults sometimes migrate to tiny bits of food that fall between cracks and crevices, so thorough vacuuming and disinfecting is essential to any pantry pest control program. Infestations often become extensive enough to warrant professional pest control intervention. According to a recent nationwide survey of pest control professionals, red flour beetles were the fourth most commonly controlled pantry pests within homes, followed by confused flour beetles at number seven.

Have you ever struggled to rid your pantry of pantry pests?

Leave a Reply