Physical Characteristics

The adult merchant grain beetle looks so close to the sawtoothed grain beetle that they were once considered one species. The merchant grain beetle’s eyes, however, are set farther back on its head, much closer to the leading edge of its prothorax. This beetle looks like a tractor-trailer from above, with its prothorax containing six saw-like teeth on each side. Adults are about 1/8 inch long and dark brown, with a flattened body. Wings are well developed. Its larva is less than 1/8 long, yellowish-white in color and is elongated, with no cerci-like protrusions on its tail, and three-segmented antennae on its head.


Merchant Grain Beetle


The merchant grain beetle is a scavenger; it cannot attack whole, unbroken kernels, but its flattened body allows it access through small cracks and into packages that aren’t well sealed. It can fly, and is attracted to light. This beetle is not as attracted to grains as it is to oilseed products – cereals and nuts. It likes cake mixes, cookies, macaroni, rice flour and rolled oats, and also will attack candy bars made with peanuts and puffed rice, along with coconut.



Inspect the above-mentioned items for merchant grain beetles or other pests, keep your kitchen and other areas clean, store items in Tupperware-type containers or sealed glass jars in a dry place, and rotate products, using your older goods first. If you think your merchant grain beetle problem is escalating, call Clark Pest Control. Our highly trained technicians have the expert knowledge to solve your pest problem quickly.

Latin name: Oryzaephilus mercator