Flour Beetles (Tribolium spp.)

Red-rust flour beetle

The confused flour beetle (Tribolium confusum) and red-rust flour beetle (Tribolium castaneum) are two of the most common flour beetles.

Red-rust flour beetle, possibly native – Indo-Australian origin.

Confused flour beetle, invasive – African origin.

Found across Australia and worldwide

Larvae:

Larvae are a white, “straight”, elongated and worm-like with a dark head. Up to 6.0 mm long.

Adults:

The adults of both species are a slim beetle, 3.0-4.0 mm long. Both are a reddish brown colour.

The red-rust flour beetle antennae end in a 3-segmented club whereas the confused flour beetle has an antennae that thickens gradually towards the tip.

Female beetles can a couple of eggs a day and can live for a year or more.

The life-cycle is normally completed in 4-8 weeks. Larvae go through between 5-11 instar stages before pupating.

They are very long lived 1-3 years.

Flour beetles do not feed on whole grains but are considered a secondary pest in stored grains as they will eat grain damaged by other pests. The do however attack a range of processed grains, flour and dry food.

Both the adult and larvae feed and cause damage.

The red-rust flour beetle are strong flyers, whereas the confused flour beetle cannot fly.

The larvae move away from light and hide within the food. Whereas the adults are attracted to light, although will hide when disturbed.

They are attracted to food with high moisture content which encourages mould growth, which is part of their diet.

  • Check all incoming food materials
  • Place all opened food stuffs in sealed plastic containers
  • Clear up any food spills

Monitoring and treatment notes:

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