30 May 2017

Christchurch and Banks Peninsula residents are being urged to keep their eyes open for any sign of the myrtle rust plant disease recently discovered in New Zealand.

Myrtle rust is an invasive fungus that attacks members of the myrtle family of plants. It could seriously damage or kill mānuka, rātā, kānuka and pōhutukawa, as well as feijoa and eucalyptus.

A plant infected with myrtle rust.

Bright yellow powdery eruptions are one of the signs of myrtle rust.

While myrtle rust is found all along Australia’s eastern seaboard, it has only just been detected in New Zealand.

As of Monday the number of properties infected with myrtle rust nationally stood at 25 – 20 properties in Taranaki, three in Northland and two in Waikato.

“Myrtle rust spores are microscopic and can easily spread across large distances by wind so unfortunately it is likely at some point that myrtle rust will reach Christchurch and Banks Peninsula,’’ said Christchurch City Council Head of Parks Andrew Rutledge.

“The Ministry for Primary Industries(external link) is doing all it can to stop the spread of the disease and has stepped up its surveillance but we all need to be on the look-out for this disease because if we can detect it early, we will have the best chance of containing its spread,’’ Mr Rutledge said.

How to identify myrtle rust

Myrtle rust only affects plants in the myrtle family. It generally attacks soft, new growth, including leaf surfaces, shoots, buds, flowers, and fruit. Symptoms to look out for on myrtle plants are:

  • Bright yellow powdery eruptions appearing on the underside of the leaf (young infection)
  • Bright yellow powdery eruptions on both sides of the leaf (mature infection)
  • Brown/grey rust pustules (older spores) on older lesions.

Some leaves may become buckled or twisted and die off.

What you can do

If you think you've seen the symptoms of myrtle rust, do not touch it.

  • Call the MPI Exotic Pest and Disease Hotline immediately on 0800 80 99 66.
  • If you have a camera or phone camera, take clear photos, including the whole plant, the whole affected leaf, and a close-up of the spores/affected area of the plant.
  • Don't touch it or try to collect samples as this may increase the spread of the disease.

Find out more about myrtle rust on the MPI website(external link).