MPI lifts ban on plant movement in Taranaki as myrtle rust spreads

Wednesday, 28 February 2018

Myrtle rust is a fungal disease that is found on plants such as pohutukawa and manuka. It has been found in six regions in New Zealand.

A ban on moving plants in Taranaki to prevent the spread of myrtle rust has been lifted because it was not stopping the wind-borne plant disease.

Six regions are now infected and on Tuesday the Ministry for Primary Industries lifted restrictions in Taranaki that have been in place for eight months.

Inspectors looking for myrtle rust wander through Pukekura Park in New Plymouth fully dressed in hazard suits.

Myrtle rust has affected 313 properties in New Zealand, including four properties in Northland, 43 in Auckland, 80 in Bay of Plenty, 29 in Waikato, 149 in Taranaki and eight in Wellington.

The ban - called a Controlled Area Notice - made it illegal to move myrtle plant material from a 20 kilometre area around Waitara.

Myrtle rust has spread to hundreds of properties across the North Island.

Despite the movement restrictions myrtle rust had continued to spread outside Taranaki, myrtle rust incident controller Dr Catherine Duthie said in a statement.

'Recent weather experienced across much of the country – warm, wet and windy – has been optimal for myrtle rust sporulation. The reasons for having a Controlled Area focused on Waitara no longer remain.'

Last June, most myrtle rust infections had been detected in plant nurseries on young plants that would be sold and moved elsewhere. The Controlled Area Notice aimed to restrict movement of susceptible plants to help reduce the spread of the disease to unaffected areas.

Since July, most detections have being found on mature trees in residential properties. This increased the likelihood that myrtle rust spores had been spreading naturally on the wind.

'Unfortunately, restricting movement of myrtle plant matter from one area could not contain the spread of the disease,' she said.

The controls would remain on individual properties that had been placed under a Restricted Place Notice.

Duthie said the local community had been very supportive to the myrtle rust response.

'We have received outstanding co-operation from iwi, garden centres and commercial nurseries, and the Department of Conservation. People have pulled together and have committed to doing all they can to protect our trees from this challenging fungus. None of us are giving up.'

Staff were continuing to investigate and remove infected plants where this would slow the disease spread and the ministry was collecting a lot of information to build a good picture of myrtle rust's impacts and spread.

'There is research under way to better understand how the fungus behaves in New Zealand conditions and to identity risk factors, resistant species and potential treatment and management tools. Communities are working together to initiate ongoing surveillance and seed banking programmes.'

She urged people to keep checking their myrtle plants and to immediately contact the Biosecurity Hotline (0800 80 99 66) if they spot any signs of myrtle rust.

Myrtle rust affects plants including pōhutukawa, ramarama, lilly pilly, rātā, mānuka, guava and eucalyptus.

New Plymouth garden consultant Adrian McLeod said he was hopeful most of the affected species would develop an immunity to the disease over time.

'As far as home gardeners go, it's just another bug we get to deal with, there are all sorts of rusts and mites out there.'

He suggested gardeners use preventative copper sulphate sprays on susceptible plants in the same way as they did with roses to prevent rose rust.

A list of plants in the myrtle family and the symptoms to look out for are available on MPI's website.