Warehouse beetle

Page last updated: Tuesday, 23 July 2019 - 1:24pm

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The warehouse beetle (Trogoderma variable), is a relatively recent discovery in Western Australia. It is a pest of grain and seed industries, a public health concern and is notorious for attacking foodstuffs in stores and in homes.

This article explains how to identify it and what to do if you suspect its presence.

This beetle was first found in Western Australia in 1989 and that infestation was eradicated. It has spread to about a dozen locations but has never established to damaging populations.

The warehouse beetle larva stage does the damage, attacking a wide range of products. All sorts of cereals, vegetable and flour seeds, notably sunflower seed, paddy rice remnants, carrot and tomato seed, and fish food may be infested. The insect thrives on cereal products such as processed animal feeds or rolled barley and oats, and recently proved to be especially fond of stored canola.

Warehouse beetle can infest a great variety of grocery commodities and seeds. Packaging materials such as second-hand grain sacks and corrugated cardboard can also harbour the pest. The larva can chew through plastic wrappers, aluminium foil, airtight plastic containers and the like.

Warehouse beetle


The larvae of the warehouse beetle are 5-8mm long and covered with thick reddish-brown setae, which gives them a hairy appearance.

Warehouse beetle larvae

The adult beetle is about 3-5mm long, with three indistinct, whitish bands across the wing covers. Dead insects may be greyer in colour. The adult does little damage and will not be as obvious as the larvae because of its short life span of 7 to 10 days.

Larvae and adults of common insects of the same family appear similar to warehouse beetle. Identification requires microscopic examination, so specimens should be sent to the Department of Agriculture and Food for positive identification.

Insects that might be confused with warehouse beetle include carpet and hide beetles, the harmless native Trogoderma or khapra beetle, the world's worst pest of stored grain. Khapra beetle currently does not occur anywhere in Australia and would have a severe impact on international trade if it became established.


Rob Emery
David Cousins