Flat grain beetle
Scientific name
Cryptolestes pusillus (Schönherr)
Classification
Primary pest; grain feeder
Order: Coleoptera
Family: Laemophloeidae
Acronym: CPU
Description
- Adults are small (1.5 to 2.0 mm), reddish brown and flattened with long bead-like antennae.
- Adults have a ridge (sublateral carina) on the head and prothorax.
- Larvae are elongate and flattened with well-developed legs.
- Larvae are pale, white to yellow in colour with a darkened head capsule and dark urogomphi present.
- Male antennae are longer (almost as long as body) than female antennae (half the length of the body); rusty grain beetle antennae are the same length in both sexes.
Images
Similar species
- Rusty grain beetle (Cryptolestes ferrugineus)
- Flour grain beetle (Cryptolestes turcicus)
- Foreign grain bettle (Ahasverus advena)
Commodities affected
- Mainly damages grain, preferably wheat
- Will also feed on beans, bulbs, cacao, cereal products, citrus pulp, copra, cottonseed, cowpeas, maize, malt barley, filberts, nutmeg, rice, sorghum, soybeans, sunflower
Signs of infestation
- Damage is not readily identifiable as being caused by this species.
Damage
- Damage is usually restricted to grain stored under high moisture conditions.
- Both larvae and adults feed on germ and endosperm.
- Heavy infestations may cause grain to heat and spoil.
- Damage may spread fungal spores through grain.
How to control
Geographic range
- Is distributed worldwide, but is more common in wet-tropical and warm-temperate regions
- Is found in Canada from Quebec west to British Columbia
Where found
- Is found mainly in grain elevators and flour mills, warehouses, farm-stored grain
- Is often confused with the flour mill beetle (Cryptolestes turcicus)
- Is probably the least damaging species of Cryptolestes in Canada
- Can survive Canadian winters only in heated structures
Life history
- Females lay eggs in crevices or loosely amongst the food.
- Larvae move actively amongst the food feeding on the endosperm or germ Adults cannot climb up glass.
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