Sawtoothed grain beetle

Oryzaephilus surinamensis (L.)


Primary pest; grain feeder
Order: Coleoptera
Family: Silvanidae
Acronym: OSU


  • Adults are small, brown, slender beetles, about 3 mm in length with serrated sides on pronotum.
  • Adults are very similar morphologically to merchant grain beetle; may be separated from merchant grain beetles based on the width of the temple (narrower in merchant grain beetle).
  • Larvae are white to pale yellow and flattened.


Similar species

Commodities affected

  • Affects oats (beetle is most often found here), wheat, barley, animal feed, flax, sunflower
  • Affects milled and processed products, dried fruit, packaged foods
  • May attack a wide variety of foods found in homes, but this may be misidentification of O. Mercator (merchant grain beetle)

Signs of infestation

  • Severe infestations can cause grain to become overheated contributing to further damage.
  • Beetles are capable of rapid population buildup in large bulks of grain in heated buildings.


  • Damage is generalized and not necessarily identifiable as coming from this particular species.
  • Both adults and larvae may feed on grain dust and larvae preferentially feed on the germ.

How to control

Geographic range

  • Is found worldwide and across Canada.

Where found

  • Is found in granaries, warehouses, elevators and food mills
  • Is not able to feed on sound kernels, but is able to attack even slightly damaged grain
  • Is one of the most common grain feeding insects found in grain stored on Canadian farms.

Life history

  • Pupation occurs either freely or within a cocoon consisting of particles of grain.
  • This species requires high temperatures, but it can tolerate low relative humidity.
  • Sawtoothed grain beetle is more cold-hardy than the merchant grain beetle.
  • Species is able to survive Canadian winters in unheated structures.


Not what you're looking for?

Start over again from the insect identification keys page.

Date modified: