Farm Forestry New Zealand
PESTS AND DISEASES OF FORESTRY IN NEW ZEALAND
The Australian dampwood termite, Porotermes adamsoni, in New Zealand
From MAFBNZ Forest Biosecurity Consultative Committee, Thursday 6 March 2008.
New Zealand has experienced termite incursions for many years, but in light of recent new finds, Bruce Philip presented an update on MAFBNZ’s activity in this area.
P. adamsoni is a ‘cool climate’ termite native of south eastern Australia. They are known to attack eucalypts, radiata pine and other trees, and are a pest of forest trees in Australia. In New Zealand they present a threat to commercial and native forests, and to some wooden structures. New Zealand houses, unlike those in Australia, are not built to ward off termites. Incursions have been associated with historically-imported Australian hardwood timber (e.g. railway sleepers, telegraph poles etc), although there have been 2 detections in local timber – one in a eucalypt tree and the other in a silver birch tree. The silver birch tree was noted to be close to railway sleepers that showed evidence of termite damage. Dampwood termites could adapt to New Zealand conditions, and will eat radiata. They prefer decaying or damaged wood for establishing a colony; this includes dead wood on a living tree. Simon Cook noted that the silver birch referred to above was alive, but subsequently died as a result of the termite damage.
Colonies are difficult to detect visually, as the termites do not forage away from the colony. Alates (flying reproductive adults) are sometimes found – they are attracted to light and have been found inside houses. Thermal or microwave imaging is one way of detecting colonies.
Eradication of colonies typically involves host destruction, but where this is not possible, treatments can be applied. These include injecting insecticide or wrapping and fumigating with methyl bromide – it will depend what is most practical given the location. MAFBNZ is running three P. Adamsoni responses, at Lyttleton, Kaipara and Auckland. The Lyttleton port response dates back to 1963, and although eradication is not possible because the termites are deep inside the timber construction of the wharf, the incursion is considered contained. A pest removal company is called in whenever termite activity is exposed, and no termites have ever been detected outside the confines of the port area.
The Kaipara incursion arose from the detection of alates in February 2007. The location of the colony is unknown and surveillance is underway to locate it. This will be done by trapping during the flying season. The find is close to historically-imported Australian hardwood timber.
The Auckland incursion was detected in February of this year, and again the location of the colony is unknown and surveillance is underway to locate it. The location is close to a railway line, so again there is a probable link to historically-imported Australian hardwood timber.
Paul Bradbury noted that there were a lot of termite incursions recorded in the 1960’s and 70’s, and asked if those sites were still being followed up. Bruce replied that a major study had been done of hundreds of sites, and showed that all the colonies were eradicated bar the Lyttleton port site. John Bain of Scion had joined the meeting for a short time, and commented that since those finds were confirmed as eradicated, not so much follow-up is done now compared to previous years.
Should there be more detections in the future. MAFBNZ will assess each one and respond appropriately.
Bruce Philip, Adviser Plant Response, MAF Biosecurity NZ
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