What is the western drywood termite?
The western drywood termite (Incisitermes minor) is a wood boring insect. It's classed as an unwanted pest in New Zealand. They are not known to be present here but have been found in vessels in the past which have come to New Zealand from North America. This termite is found in parts of the USA, Mexico, and Japan. While it is adapted to a hot, arid environment, it has successfully expanded its range into temperate and subtropical climates.
The western drywood termite is found within wooden materials. It gets all its required nutrients from wood fibres. This termite requires very little moisture for survival. Multiple colonies can infest a single piece of suitable wood.
Risk to New Zealand
Termites can attack a wide range of timber types, both hard and softwood. They may even attack treated timbers, and plywoods and timbers considered termite resistant.
They can attack dry wood in trees and plants, but the main concern is this species’ destructive ability within man-made wooden structures like boats, furniture, and other items.
Finding termites is difficult, as they usually don’t damage the outer surface of the wood they live in. Colony growth is slow and, because their colonies are well hidden, these termites may exist undetected for years.
The species has been seen overseas to cause extensive damage to private dwellings, culturally significant carvings, and timber industries. It is a major pest throughout the USA. Colonies will infest both dry and less often, treated wood.
Focus on marine vessels
The movement of infested vessels represents a major risk of spreading this pest termite between and within countries. There is also a risk of spread through movement of infested wooden material from the vessel – for example, during repairs and renovations.
Signs of a termite colony
Small piles of their droppings (known as frass) are the most obvious signs of a colony inside a wooden object. These pellets are about 1mm long and appear in mounds directly below small holes in wooden materials. They vary in colour from cream to red to black.
Drywood termite produce swarms of winged termites at certain times of the year, usually during summer. The 8mm to 12mm long adults are attracted to the light and can be found at windows at night, or in light fittings and spider webs.
Termites discard their wings after landing in a new location. If there has been a swarm of winged termites in your surroundings, you may find their wings.
What to do if you suspect a termite colony
Any potential finds of the western drywood termites should be photographed and reported to the Biosecurity New Zealand Exotic Pest and Disease Hotline on 0800 80 99 66.
You can also report sightings using our online form.
What we are doing
Biosecurity New Zealand is monitoring the immediate area surrounding the single Tauranga find. We're providing advice to marina users and vessel owners on detecting termite colonies.
Biosecurity New Zealand has responded to 5 responses for the same species since 2005, all in imported vessels with clear entry pathways. As with this detection, in all cases the colonies were eradicated. There have been no reports to date of any incursion for this species without a clear entry pathway.