Merchant grain beetle

Oryzaephilus mercator (Fauvel)


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


  • Adults are small brown slender beetles, about 3 mm in length.
  • Adults are very similar morphologically to sawtoothed grain beetle. May be separated from sawtoothed grain beetles based on the width of the temple (wider in sawtoothed grain beetle).
  • Larvae are white to pale yellow and flattened.


Similar species

Commodities affected

  • Prefers foods with high oil content such oatmeal, bran, rolled oats, brown rice
  • Will also feed on processed cereals, dried fruit, seeds
  • Feeds on flour, cake mixes, pasta, cookies, nuts, coconut, puffed rice, pet food

Signs of infestation

  • Damage is not readily identifiable as being caused by this species


  • Damage is generalized and not necessarily identifiable as coming from this particular species.
  • Both adults and larvae feed readily causing damage.
  • In dwellings, they are normally carried into the house with food.
  • In apartment buildings, they sometimes migrate, spreading from unit to unit and become a chronic pest.

How to control

Geographic range

  • Is distributed throughout Canada

Where found

  • Is primarily a problem in homes
  • May be an issue where grains with high oil content are going out of condition

Life history

  • Females lay up to 200 to 300 eggs over a 3-month period.
  • Pupation occurs either freely or within a cocoon consisting of particles of grain.
  • This species requires high temperatures and can tolerate low relative humidities.
  • This species is not particularly cold tolerant.
  • It does not survive Canadian winters in unheated structures.

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