DOC Expert tree climber Tertia Thurley climbs an old growth Kahikatea tree to collect seed from the rātā growing in the tree

Image: Wendy Holland | DOC

Introduction

Whangārei DOC staff are dangling from cliff edges and climbing trees to safeguard the threatened rātā vine species, carmine rātā, from myrtle rust.

Date:  14 May 2018

“Although this work sounds like fun, it’s crucial for the future of native myrtle species,” DOC Operations Manager Louisa Gritt says.

DOC is leading a national program of seed collection of myrtle species in response to the threat from myrtle rust. As part of this, carmine rātā (Metrosideros carmineaseeds were collected from Bream Head and Mount Manaia and then sent to a national seedbank where they will be securely stored.

DOC ranger Laurence Sullivan describes his experience collecting the seeds: “It was very tricky and time-consuming setting the ropes up on a cliff edge, and we didn’t even know if there would be any seed! But it was worth it to retain the whakapapa of this tiny taonga from Te Whara (Bream Head).”

Since its first discovery on mainland New Zealand in May 2017, myrtle rust has been confirmed in over 600 mainland sites.

The first infected plants found on New Zealand’s mainland were discovered in Kerikeri in May 2017. These were destroyed, and the disease eradicated locally. Unfortunately, myrtle rust has recently reappeared in Northland with an infected tree in Kaipara and numerous urban properties in Kerikeri now infected.

Myrtle rust is a fungal plant disease that threatens the myrtle plant family, including some of our most iconic indigenous plants. These include pōhutukawa, rātā, mānuka, kānuka, and ramarama.

Background information

What is myrtle rust?

The fungal plant disease myrtle rust (Austropuccinia psidii) was discovered on Raoul Island in the Kermadec group of islands in March 2017. It was later confirmed on mainland New Zealand, at a Kerikeri plant nursery on 3 May 2017 and at Waitara, Taranaki, on 17 May 2017. 

Spores are thought to have crossed the Tasman Sea from Australia to New Zealand on wind currents associated with recent weather events.

What to look for?

Myrtle rust generally attacks soft, new growth, including:

  • leaf surfaces
  • shoots and buds
  • flowers, and fruit.

Symptoms to look for 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.
  • grey, 'fuzzy' spore growth on undersides of leaves.
  • leaves may become buckled or twisted and die off.

What should you do if you find myrtle rust?

  • Don't touch!
  • Don't collect samples as this might spread the disease.
  • If you can, take photos of the rust and the plant it's on.
  • Call Ministry for Primary Industry’s exotic pest and disease hotline 0800 80 99 66.
  • If you accidently come in contact with the affected plant or the rust, bag your clothing and wash clothes, bags and shoes/boots when you get home.

Contact

Ayla Wiles, Ranger, Community & Biodiversity
Mobile: +64 7412 0969
Email: awiles@doc.govt.nz

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