MPI initiating immediate response to myrtle rust

Myrtle rust (Supplied)
Myrtle rust (Supplied)

The Ministry for Primary Industries (MPI) has initiated an immediate response after finding fungal disease myrtle rust on mainland New Zealand for the first time.

Primary Industries Minister Nathan Guy is urging people who have bought plants from Kerikeri nurseries to check them for myrtle rust, but not to touch it.

The fungal disease can cause serious damage to numerous species of both native and introduced plants in the myrtle family, including pohutukawa, rātā, mānuka, gum, bottlebrush, guava and feijoa. It's also known as guava rust and eucalyptus rust.

The disease can travel vast distances on the wind. Officials believe it’s likely that wind carried spores to mainland New Zealand from Australia.

Eradication of the disease is particularly challenging because once it is visible to the naked eye, the spores are already dispersing. 

MPI says "there is no known method of controlling the disease in the wild, apart from application of fungicide in very small areas as a last resort. Even if eradication is achieved, there is an ongoing risk of reinfection from Australia. "

The disease was found on five pohutukawa seedlings at a nursery in Kerikeri. It was spotted on Tuesday night, and Mr Guy says laboratory testing has now confirmed it is the deadly fungus.

"MPI has moved quickly and initiated a Restricted Place notice to restrict the movement of any plants and people at the site, and is treating nursery stock with fungicide spray as a precaution.

"Work is also underway to trace any stock that has left the nursery and all other nurseries in Kerikeri are being inspected today," Mr Guy said in a press release.

Conservation Minister Maggie Barry says the Government has been working on measures to manage and adapt long-term, if necessary, to the expected arrival of the fungus in New Zealand. 

 "This includes accelerating work already underway to collect and store germplasm from affected species, searching for signs of resistant myrtle strains which could be incorporated into a breeding programme and monitoring at 800 locations across the country," Ms Barry said.

"DOC will also be conducting inspections of our myrtle species on public conservation land in Northland for any early signs of the fungus."

New Zealand has a complete ban on imports of flowers and foliage from all myrtle species from New South Wales, Queensland and Victoria.

Information about myrtle rust via the Department of Conservation

  •  Individual myrtle rust spores cannot be seen with the naked eye; however large amounts of spores grouped together are visible as yellow rust bodies.
  • The identifying signs of myrtle rust are purple/black splotches or patches (lesions) with yellow dots on leaves and stems. These can appear as bright yellow powdery eruptions on leaves. Leaves and stems especially when young can become buckled or twist and die off.
  • Severe infections can kill infected plants.
  • By the time lesions are visible, spores are already dispersing. This makes eradication difficult as the disease is already spreading by the time it can be seen.

Touching the plant's infection willl help spread the disease. Do not touch it. Wash any tools and clothing that may have come into contact with the infection, and report the infection to MPI on 0800 809 966.