Scientists examine a soil sample in the Waipoua Forest as the operation to stop the spread of the disease ramps up

Multi-agency fights kauri dieback

by Andy Bryenton

At a pair of public meetings on July 1 and 2, in Dargaville and Kaihu respectively, the team from Te Roroa Manawhenua Trust and the Department of Conservation fronted up to the public with the current status of the fight against kauri dieback.

A team of experienced scientists and forest conservation management experts has been assembled under the auspices of DOC, the Ministry for Primary Industries, Northland Regional Council and Te Roroa to gather data on the spread of Phytophthora agathidicida, the sporing organism responsible for the dieback disease. A large crowd attended the meeting in Dargaville, where a panel of six speakers gave evidence that extensive work is being undertaken to stop this ‘clear and present threat’.

The good news is the spread of Phytophthora, and its function in infecting the roots of kauri is now well understood. The prime vector for its spread is the movement of infected soil. As in the Waitakere area, a massive proportion of infected tree sites are near hiking trails, with dirt spread via boots and equipment. Another means of transmission are wild pigs, leading to a programme of wild pig elimination, which has recently brought local hunters on board. Te Roroa were recipients of a 2019 NRC environment award for their work in the Waipoua Forest on this topic.

More grim is the news that iconic stand the Four Sisters has tested positive for kauri dieback, and that an infected soil sample has been confirmed only 25 metres from Tane Mahuta himself. New measures to track and thus block the spread of the disease include the adoption of drone-mounted infrared spectrum cameras, while lab work and some field tests are underway exploring various possible cures.