Rusty grain beetle
Cryptolestes ferrugineus (Stephens)
Primary pest; grain feeder
- Adults are flat, small, shiny reddish brown beetles, about 2 mm in length and are as thick as 2 Canadian dimes.
- Larvae are 1 to 4 mm in length, are white to yellowish white with a brown head and have a slightly darker last segment with 2 amber projections (urogomphi).
- Wheat, barley, rye, triticale, oats, and occasionally milled products
- Flax that has heated
Signs of infestation
- Damage is not readily identifiable as being caused by this species.
- High population may be associated with heating grain.
- Both larvae and adults feed on germ and endosperm.
- Heavy infestations may cause grain to heat and spoil.
- Beetles may spread fungal spores through grain.
- They are the main insect pest of farm-stored cereals in Western Canada.
How to control
- Is widely distributed throughout the world and across Canada
- Is a common pest in cargo ships, railroad cars, farm stored grain, grain elevators
- Is infrequently found in mills, warehouses and flour mills
- Is one of the most common grain feeding insects found in grain stored on Canadian farms.
- Each female is capable of laying 200 to 500 eggs, depositing them on or among grain kernels and debris.
- Upon hatching, larvae seek out food preferring to feed on the germ of the kernel.
- Reproduction slows considerably when the temperature is below 23°C.
- Adults will not fly below 21°C.
- Grain below 12% moisture content, or relative humidity below 40%, will restrict development.
- Adults are unable to climb glass.
- Rusty grain beetles have one of the highest rates of population growth for stored-product insects.
- Rusty grain beetles are one of the most cold tolerant stored product insects.
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Video of Rusty grain beetle
Adult rusty grain beetles move across and under grains of wheat. On the left of the viewer, one of the beetles enters a hole in one of the grains. Many of the grains have holes that are typical of damage caused by rusty grain beetles.
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