Myrtle rust is in NZ to stay - DoC

The MPI and DOC have given up all hope of ridding the country of myrtle rust.

The Ministry for Primary Industries and the Department of Conservation say the fight against myrtle rust is changing gear, given the prevalence of the disease across "susceptible" parts of the country.

Myrtle rust has now been confirmed in Tasman, at the top of the South Island, which means it has reached almost all regions identified as most vulnerable based on habitat suitability and wind patterns.

"When myrtle rust was first discovered on mainland New Zealand (Kerikeri) in May last year, we said it would be a challenging disease to contain and eradicate, but we would give it a good crack," MPI spokesperson Dr Catherine Duthie said.

"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."

The ministry has also confirmed infections on five properties on the south-western edge of Lake Taupo, another new region.

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"We now have well over 540 infected sites across the North Island, and now the top of the South," Dr Duthie said. "Because of the windborne, pernicious nature of the disease, we have to anticipate that there are likely to be many more infected sites beyond these."

The focus now had to go on to developing a science programme to increase understanding the disease, treatment, resistance and susceptibility, and improve seed banking efforts.

"A second key focus has to be on working with communities across New Zealand to support regional efforts to combat myrtle rust," shesaid. "As we transition to long-term management, MPI and DOC will be engaging with iwi and hapu, territorial authorities, plant and nursery industries and communities to support development of regional programmes.

This could include regional surveillance programmes, identification and protection strategies for taonga plants and special locations, advice to land owners, seed banking and broad community engagement."

As part of involving and informing communities, MPI and DOC would organise hui with iwi and councils in affected regionssoon.

"We think this regional and community effort is really important," Dr Duthie said. "One of the most critical things is for people to continue to report suspected infections. 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."

More than 540 properties were known to have been infected since the disease was first detected in a nursery in Kerikeri 11 months ago. Since then, more than 5000 myrtle plants had been destroyed, and more than 95,000 inspected.

The public were encouraged to continue to report any possible cases to the Biosecurity Hotline (0800 809-966).

DOC would focus on seed collection to secure the long-term future of native myrtle plants — such as pohutukawa and rata — and monitoring biodiversity effects to inform science and management actions. It would also continue to protect sites of high ecological and cultural significance.