Foresters are now watching for Myrtle Rust to spread across the length of New Zealand after the pathogen was found for the first time in the South Island last month.
After being found near Nelson, it now appears to be a matter of time before the whole country is infected and that could hit a key forestry species that is a major source of export chip from Southland – Eucalyptus.
The Myrtle Rust fungus poses a serious threat to many myrtle species plants, including Pohutukawa, Manuka, Kanuka and Rata, as well as Australian trees like Eucalyptus.
Following the latest find, the Ministry for Primary Industries (MPI) says it is pulling back from trying to eradicate the fungus to an approach of long-term management.
Since first being found in a Kerikeri nursery last year, the disease has spread to hundreds of sites across the North Island and now to a home in Collingwood in Golden Bay and a commercial property at Pohara. It has also been detected on the southwestern edge of Lake Taupo, a new region for infection.
More than 5000 myrtle plants have been securely removed and destroyed, and more than 95,000 myrtle plants inspected.
"When myrtle rust was first discovered on mainland New Zealand in May last year, we said it would be a challenging disease to contain and eradicate but we would give it a good crack," says MPI's Myrtle Rust response spokesperson Dr Catherine Duthie.
"There has been an enormous operational effort over the last 11 months, but the windborne nature of the disease means that containment has not proved possible.
"We have signalled for a while the likely need to change gear from intensive surveillance and the removal and destruction of host plants, to one where we look to manage the disease over the long term."
Dr Duthie says the focus now is on a science programme designed to lift understanding around the disease such as ways to treat Myrtle Rust, resistance and susceptibility and to improve seed banking collection.
"A second key focus has to be on working with communities across New Zealand to support regional efforts to combat myrtle rust," she adds.
"As we transition to long term management, MPI and DOC will be engaging with iwi and hapu, territorial authorities, the plant and nursery industries, and communities to support the development of regional programmes.
"This could include regional surveillance programmes, identification and protection strategies for taonga plants and special locations, advice to landowners, seed banking and broad community engagement."
"We need to keep tracking the spread of the disease so we can better understand how it might behave in New Zealand and what its long-term impacts might be.
"This will help us to understand resistance of native species and will be vital to our Myrtle Rust science programme."
The Department of Conservation will continue seed-banking work to secure the long-term future of native myrtle plants.
Reports of possible Myrtle Rust infestations can be made to the Biosecurity Hotline 0800 80 99 66.
Posted on Thursday 12th April 2018
MPI throws in towel as Myrtle Rust spreads
Myrtle Rust on a Eucalyptus Olida leaf.
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