Warehouse beetle (Trogoderma variabile)

The warehouse beetle is an invasive pest in New Zealand.

Widely distributed in Europe, North America and other temperature areas of the world.

Although there have been a couple of interceptions in New Zealand, it is not believed to have established in New Zealand.

Larvae:

Larvae can be 5-8 mm long and are covered with reddish brown hairs. They have a very similar appearance to carpet beetle larvae – “woolly bears”.

Adults:

Adults are an oval beetle, 3-5 mm long, with 3 light bands across the wing covers.

Can be confused with carpet beetles, especially the larvae and the adults can be confused with the variegated carpet beetle. Can also be confused with the khapra beetle which is often considered as the “world’s worst stored grain pest”. However, the khapra beetle is not currently in Australia.

Female beetles can lay up to 90 eggs in her lifetime.

The life-cycle takes 2-4 months to complete, with the larvae going through several moults before becoming an adult.

Under sub-optimal conditions, they can slow their life-cycle moulting numerous times before pupating. When food is scarce the larvae can enter diapause (an extended period of inactivity).

Adults only live for 7-10 days.

Only the larvae cause damage.

Warehouse larvae will eat seeds and grains but also dry packaged foods. They will also a range of animal material including bee and wasp nests, rodent and insect carcases and droppings.

The larvae are able to chew through packaging and even plastic containers.

Adult warehouse beetles are excellent flyers and can disperse quite easily.

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