Sixty Years of Defence: Biological Style

22 December 2008

Protecting New Zealand’s borders and pristine environment is a tireless business, no more so than for those dedicated men and women who spend their days in the company of bugs, moths and diseases.

If it weren’t for the commitment of this small team of entomologists and pathologists, some of New Zealand’s valuable forest resources could already have been lost.

More than 60 years ago in 1947 a team of three scientists were brought together as the pathology group, part of the newly-formed New Zealand Forest Research Institute, in recognition of the threat of new forest pests entering the country.

Back then, the blackberry was a nasty weed and notebooks were made of paper, but over the years some things haven’t changed.

Now an integral part of Crown Research Institute Scion, the group operates out of the organisation’s Rotorua and Christchurch campuses. They are charged with the responsibility of protecting New Zealand’s plantation, native and urban forests from overseas invaders, and dealing with those resident populations that the nation wants to see ejected.

Group Manager, New Forests and Forest Science, Dr Brian Richardson, says that whether it’s rearing hundreds of foreign moths in quarantine for research into their susceptibility to pesticides, or providing diagnostic testing on imported trees, the defence of New Zealand’s plantation forestry is no small task.

"Scion’s Forest Protection team is responsible for managing risks to the forest environment including preventing pests and diseases from entering the New Zealand plantation forest industry, and eliminating or managing those that are already here.

"In addition, we are continually building our understanding of the forest ecosystem, and its resistance and resilience to pests.

"As a result, there are times when we have introduced a new biological control agent into New Zealand such as in 2006, when a Chinese weevil Cleopus japonica was released to help control buddleia, a serious forest weed found across the country.

A focus for the group back in the 1950s and 1960s was a wood wasp that laid eggs inside the stems of pine trees. In response, parasitic wasps were released to prey on the wasp. This remains the largest ever biological control programme directed against a forest pest in New Zealand.

Dr Richardson says the past sixty years have seen a range of threats to the New Zealand forest industry, some of which have been successfully eradicated, others of which provide ongoing focus for more research and improvement to management practices.

Scion scientists were critical players in the downfall of both the white-spotted tussock moth in 1996, which threatened the country’s fruit trees and ornamental trees, and the painted apple moth, successfully eradicated after a sustained campaign ten years later.

Researchers at Scion provided technical advice on the insects and their ecology, and helping to design the aerial spray operations that combated the pests.

The work of the Forest Protection team is not entirely focused on insect pests as pathogens and diseases also have the potential to devastate New Zealand’s forest resources.

Dothistroma is one of the most serious diseases affecting radiata pine, costing the industry about $23 million per year in treatment and lost growth. This damage would be much higher if it weren’t for the research undertaken by Scion into the use of copper sprays as a cost-effective means of disease control.

Dr Richardson is confident there will be no let up from invaders in the coming years, with the impact of a changing climate making New Zealand even more attractive to certain pests and diseases that will be looking to migrate.

"We might not be armed with sky hawks or frigates, but our defence team is poised for another sixty odd years of forest protection, both for the forestry industry and for anyone who enjoys the natural environment New Zealand has to offer," he concludes.

The importance of forest biosecurity as an international issue is being recognised with the gathering of national and international specialists in Rotorua, in March 2009.

The IUFRO International Forest Biosecurity Conference will run March 16-20 and attendees will discuss issues relating to the exclusion, eradication or effective management of pests to protect the diverse benefits offered by forests worldwide.