Grain Beetle

Oryzaephilus surinamensis

The Saw-Toothed Grain Beetle is almost identical in appearance to the Merchants Grain Beetle (Oryzaephilus Mercator). Both pests are scavenger feeders. They do not attach sound grains. They are cosmopolitan pests of broken stored grains, cereal products, dried fruit, oilseeds and other processed foods including oatmeal, flour, macaroni, nuts, sugar, chocolate, dried meats and many other products. Their physical design makes these pests notorious for entering packaged materials on the store shelves. Their extremely flat body design allows them to enter most seems in packaged foods.

Saw Tooth Grain Beetle

Saw-Tooth Grain Beetle

*Courtesy Insects Limited, Inc.
How Does it Work?

As insects contact and lay eggs on the surface of the ProvisionGard treated packaging, they absorb the insect growth inhibitor and cease evolving to their next stage of the growth cycle and die without contributing to insect population growth. ProvisionGard is a non toxic technology and will not kill a live adult insect but will control the eggs and offspring of adults to systemically and safely protect food stuffs.

Download the ProvisionGard PDF to learn more.


What is the Sawtoothed Grain Beetle?

The sawtoothed grain beetle, Oryzaephilus surinamensis (L.), is a widely distributed species commonly found in stored grain. It is often confused with a closely related species, the less common merchant grain beetle, Oryzaephilus mercator (Fauvel). In Pennsylvania, the sawtoothed grain beetle is not a major problem in stored grains, but can be found coexisting with other insects in contaminated grains. Both the larval and adult stages of the merchant grain beetle attack all foods of vegetable origin; their preferred foods are oilseed products such as nuts and sunflower seeds.

What is the Sawtoothed Grain Beetle life cycle?

The habits and development of the two species are similar. The merchant grain beetle, however, is less cold tolerant and lays only about one-half to two-thirds as many eggs as does the sawtoothed grain beetle. The adult merchant grain beetles are strong fliers and may originate from other areas; they also are introduced into new grain from contaminated grain. The adults of the sawtoothed grain beetle, on the other hand, cannot fly and must be introduced from contaminated grain.

Adults live an average of six to ten months, but can live as long as three years. The females lay between 43 and 285 eggs during their lifetime. Eggs are dropped loosely among grain kernels or tucked into a crevice in a kernel. The tiny eggs are slender and white, and hatch in three to five days when environmental conditions are optimal (80° to 85°F).

The larvae emerge and crawl freely about the grain to feed on broken kernels. Larger larvae may tunnel into kernels to feed. Larvae mature in about two weeks, and construct cocoon-like coverings by joining together small grains or pieces of grain. Within these structures the larvae pupate. the pupal stage lasts about a week. Total development from egg to adult requires about three to four weeks.

Why are Sawtoothed Grain Beetles pests?

Although broken kernels are the preferred food of both species, sound kernels will sometimes be penetrated and fed on. The dry weight of grain may be reduced, but total weight may increase because of water absorption caused by the metabolic processes of insect populations. Molds may begin to grow on the gain, further reducing grain quality and value. The presence of live insects and/or insect parts can also result in reduction of grain value. In some cases, grain can be rejected at the terminal.