Rusty grain beetle
Cryptolestes ferrugineus (Stephens)

Classification

Primary pest; grain feeder
Order: Coleoptera
Family: Laemophloeidae
Acronym: CFE

Description

  • 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).

Similar species

Commodities affected

  • 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.

Damage

  • 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

Geographic range

  • Is widely distributed throughout the world and across Canada

Where found

  • 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.

Life history

  • 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.

Images

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Video of Rusty grain beetle

Transcript

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.