18 November 2016

A disease which is devastating trees in the Western United States and Europe is a major threat to New Zealand plantations and ornamental trees, should it ever arrive here.

The forest industry is concerned that even the suspicion that Phytophthora ramorum was present in New Zealand could have a major effect on log exports and employment in forest regions.

P. ramorum is causing the now widespread disease, sudden oak death, in California and Oregon.   It has also spread to most European countries in the past decade.

Forest Owners Association Biosecurity Manager, Bill Dyck, says the disease is just one of many pests and diseases threatening the industry.

“Just this year, we’ve had two species of beetles, which feed on eucalypts, arrive in our forests.  One, near Waikanae, we thought had been eradicated, and the other, in Hawkes Bay, we haven’t ever seen here before,” Bill Dyck says.

Rotorua based Scion plant pathologist, Lindsay Bulman, says one of the concerns is the ramorum pathogen is infecting an increasing range of tree species.

“We don’t know if ramorum would infect our main plantation tree, Pinus radiata, but it has now been seen on Douglas-fir and Japanese larch overseas, and previously plant pathologists thought it wouldn’t infect any conifer species,” Lindsay Bulman says.

Ornamental trees which are particularly susceptible are rhododendron, camellia and viburnum.

“I have to emphasise as well, that implications of any arrival of this pathogen in New Zealand may not be confined to potential effect on the trees themselves.  Log exports from the West Coast of the United States to East Asia have had a major hit from importing countries not wanting to introduce the pathogen there.”

Lindsay Bulman says the threat of importing P. ramorum and many other plant pests and pathogens is behind next week’s Biosecurity Week at the Port of Tauranga. 

“Trees and vines are the Bay of Plenty’s biggest businesses and the forest and kiwifruit industries share a concern that it would be so easy for insects or pathogens to slip through the border if tight vigilance is not maintained.”

“There are various eradication or control options, so long as new incursions are detected early.  Surveillance by specialists and biosecurity awareness from the public are crucial for early detection.”

Lindsay Bulman says Biosecurity Week aims to heighten awareness of the risk and what the public can do to help.

“A third of New Zealand’s five-billion-dollar a year forest product export trade goes through the Port of Tauranga.  If those exports were disrupted, there would be a lot of people who work at, and service, that Port, who might find themselves out of work for a long time.”