Department of Conservation banking on more seeds to save native trees from myrtle rust fungus

More than two years after the Department of Conservation started collecting native myrtle species seed as a protective defence against the myrtle rust fungal disease, nearly 70 per cent of its wishlist has been gathered.

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Seed banking is vital to make sure trees like pohutukawa and manuka aren't wiped out by the fungus. Source: 1 NEWS

The department is now reviewing how much viable seed has been collected and how it will react to being frozen for the long-term, with the help of the New Zealand Indigenous Flora Seed Bank.

“It will really help guide what we need to focus on so obviously we don’t have all the money in the world so we're going to reprioritise on what are most at risk,” DoC myrtle rust operations advisor Suliana Teasdale told 1 NEWS.

She said at the moment that is the ramarama and rohutu trees.

With little information on myrtle species, those storing the seeds after they’ve been collected are learning as they go.

“Every species respond differently when we do a germination test. We are still learning and seeing how many collections we have complete or not and what species we should prioritise,” NZIFB seed bank officer Cristina Winkworth said.

A lot of the seeds collected by rangers have not contained enough quality seed to be stored so DoC staff will have to collect more.

“It’s our biggest priority at the moment behind monitoring the spread,” Ms Teasdale said.

“There’s just so many things that we didn’t know that we’re slowly learning more and more about.”

Ms Teasdale said New Zealand has reacted quicker to collect seed than in Australia but hopes a proactive decision is made to extend the collection to all natives.

"And we start learning about everything we have before something comes in and impacts it in a harmful way. So we’re not racing.”

Ms Teasdale said building a complete myrtle seed collection could take five to 10 years.

Even then, collections will need to be topped up as viability decreases and as seeds are tested for successful germination.

“Until we get this data on how long-term storage is affecting the seed, we don’t know what those populations will look like as stored seed,” Ms Teasdale said.

The Government has put more than $23 million into research to understand and combat myrtle rust since mid-2017.

“We definitely need more, a New Zealand effort in funding seed banking,” DoC myrtle rust project manager Fiona Thomson said.

Ms Thomson said with most funding going into research, there are renewed calls for the public to report the spread of myrtle rust to DoC.

“There is a definite vibe that myrtle rust is off people’s radar now. And the department is still really concerned about myrtle rust,” she said.

The agency said Biosecurity New Zealand would love people to take a photo of suspected myrtle rust infections and send it through for identification on the iNaturalist app

“We still don’t know which species are being infected the most so that type of information is really valuable when you’re trying to understand how myrtle rust could impact New Zealand in the long term.”

Ms Thomson said myrtle rust infection increases during Spring, Summer and Autumn due to increased temperatures and humidity.