Sawtoothed Grain Beetle

Common Name: Sawtoothed grain beetle
Scientific Name: Oryzaephilus surinamensis

Inroduction. The Sawtoothed grain beetle gets its common name from the 6 teeth located on each side of the prothorax (front portion of the thorax). It is one of the most important pests of stored products found in the home and grocery stores and is worldwide in distribution.

Recognition. Adult Sawtoothed grain beetles are about 1/8 inch long, brown, and have a narrow, flattened body. There are 6 saw-like teeth on each side of the prothorax. The wings are well-developed but this beetle has not been observed in flight. The mature larva is yellowish-white, elongate, and less than 1/8 inch long.
Similar Beetles. Other small dark flat beetles (e.g., lyctid powderpost beetles) lack the 6 saw-like teeth on each side of the thorax.
Biology. The female sawtoothed grain beetle lays 45 to 285 white, shiny eggs singly or in small clusters in crevices in the food material during a 2 to 5 month period. The eggs hatch in 3 to 17 days depending on the temperature. The larva molts 3 times (range 2 to 4) and usually constructs a pupal cell or cocoon from food particles held together with sticky oral secretions. The life cycle (egg to egg) typically requires 30 to 50 days (range 27 to 375). Warmth and humidity provide optimal developmental conditions . There may be as many as 6 to 7 generations per year but the number is greatly dependent on temperature. On the average, adults live 6 to 10 months but may live longer than 3 years.

Habits. The sawtoothed grain beetle does considerable damage to grains but it cannot attack sound kernels. Its flat body form permits access through very small cracks and into imperfectly sealed packages.
Adults are not known to fly and are not attracted to light. Sawtoothed grain beetles attack an extremely wide variety of foodstuffs which include cereals, bread, breakfast foods, macaroni, dried fruits, nuts, sugar, chocolate, dried meats, candy bars, drugs, tobacco, and many other products

Cultural Control & Preventative Measures. The first step towards stopping an infestation of sawtoothed grain beetles is locating and, if possible, removing the food source(s) or excluding the breeding site(s). Beetles, larvae and pupae can be removed using a vacuum cleaner fitted with a hose attachment. Dried grain, seed, vegetable, fruit, snack foods and other vulnerable items should be stored in airtight, thick-walled containers until needed. Rodent bait that has been stashed away in structural voids by invasive mice, may be infested by beetle larvae and can be difficult to locate and treat.

Professional Control. A Rottler pest management professional will assist in locating sawtoothed grain beetle breeding sources and making recommendations for preventing re-infestation. A spot treatment of an infested structural void using a residual insecticide dust, or a crack and crevice treatment into cabinet corner seams and shelf junctures using non-residual or residual insecticide aerosol formulations may be applied by the technician to stop additional pest breeding.
Larvae that form pupae in crevices may not give rise to new adult beetles for weeks. Therefore, good sanitation and food-storage practices must be maintained perpetually, once a sawtoothed grain beetle infestation of has been detected and treated.