Merchant grain beetle
Oryzaephilus mercator (Fauvel)
Primary pest; grain feeder
- 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.
- 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
- Is distributed throughout Canada
- Is primarily a problem in homes
- May be an issue where grains with high oil content are going out of condition
- 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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