HEADS UP:: Myrtle Rust has arrived in NZ!

Myrtle rust (Austropuccinia psidii) is also known as guava rust and eucalyptus rust. It is a serious fungal disease that attacks various species of plants in the Myrtaceae family, also known as the myrtle family, that includes Pohutakawa and Manuka. It is found in many parts of the world including New Caledonia and all along Australia's eastern seaboard.

Myrtle rust spores are microscopic and can easily spread across large distances by wind, or via insects, birds, people, or machinery.

A biosecurity response is underway after the detection of myrtle rust on mainland New Zealand for the first time in May 2017. MPI has 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.

 

THE RISK:

Myrtle rust could affect iconic New Zealand plants including pōhutukawa, mānuka, rātā, kānuka, swamp maire and ramarama, as well as commercially-grown species such as eucalyptus, feijoa and guava.

Severe infestations can kill affected plants and have long-term impacts on the regeneration of young plants and seedlings.

It is not known how this disease will affect New Zealand species. Overseas its impacts have varied widely from country to country and plant species to species.

 

IDENTIFYING 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 to do if you see myrtle rust

·         Don't touch it.

·         Don't collect samples as this might spread the disease.

·         If you can, take a photo of the rust and the plant it's on.

·         Phone MPI's exotic pest and disease hotline 0800 80 99 66.

·         If you accidently come into contact with the affected plant or the rust, bag your clothing and wash clothes, bags and shoes/boots when you get home.

 

Image credit: Forest and Kim Starr, Creative Commons.

Twyla MacDonald