Myrtle rust is a fungal disease affecting New Zealand’s native Myrtaceae family. More than 60 million Myrtaceae seeds have been collected for long term storage to future proof these plants from the disease. Technical Threats Advisor Jacqui Bond has been working on the collection of seed from populations of 37 threatened species around the country.
Myrtle rust threatens the Myrtaceae plant family, including some of our most iconic native plants. These include pohutukawa, rātā, mānuka, kānuka, and ramarama. Once a plant is infected with myrtle rust, the only cure is the removal of the infected part of the plant, otherwise it may result in its death.
Myrtle rust spores.
In March 2017, the fungal disease myrtle rust was discovered on Raoul Island. Inevitably, two months later it was found on mainland New Zealand. On discovery, panic buttons were hit, and a specialist team was put together to come up with a plan to save the precious Myrtaceae family.
A seed collection plan
A plan was devised to preserve our native Myrtaceae by collecting seed from populations of the 37 threatened species around the country.
If possible, each collection would contain 10,000 seeds from 50 or more plants, and would include three dried and pressed plant specimens. Seed would then be saved in the New Zealand Indigenous Flora Seed Bank (NZIFSB), with the plant specimens which vouch for the seed stored in the Dame Ella Campbell Herbarium at Massey University and the Allan Herbarium in Christchurch.
The NZIFSB is a truly unique set-up. It is a partnership between ourselves, Massey University, AgResearch, NZ Plant Conservation Network and Landcare Research. It is coordinated by Massey University. Our collection of Myrtaceae for seed banking is the largest targeted native seed collection ever undertaken in New Zealand.
Surveying northern rata for myrtle rust.
The early days
In May 2017, our staff were given the urgent task of collecting disease-free seed from 37 native Myrtaceae species in the North and upper South Island. The task required staff not just to find and identify the plants but find plants with seed ripe for collection. In collaboration with the NZIFSB, we created best practice methods for staff to collect and store seed in the short term.
Meanwhile, the national myrtle rust team appointed regional co-ordinators around the country to help feed surveillance and seed collection information back to the operations teams on a daily basis.
Work began immediately in May 2017. During a five-month window (May-September), the first two rounds of seed collecting took place, where 350 separate seed collections were completed. 27 of the 37 different myrtle species were collected by over 100 of our staff and numerous volunteers.
After this amazing effort by our staff, volunteers, iwi and hapu and the NZIFSB, the collecting season came to an end. Over winter 2017 there was time to improve what had been started.
Lessons learnt
Jacqui with a pole pruner collecting seed. 📷: Paul Cashmore
The first round of collection was a success, although we knew we could improve.
Training was severely lacking, not just in seed collecting but in plant and myrtle rust identification. We also noticed that data capture needed improving to reduce the huge load on staff as well as the seed bank.
We needed a more scientific approach to where we collected seed from in order to capture all our plant variation, and so our own Shannel Courtney created a framework that was then implemented for seed collection.
The framework is based around 49 sub-regions, where it is assumed that the genetic diversity within Myrtaceae species in a sub-region is relatively homogeneous.
41 staff were also trained in the summer of 2017/18 on all the processes around seed collection, including how to collect and send seed to the seed bank to ensure maximum long-term storage. Training courses were held in Rotorua, Wellington and Nelson.
On the way to a seed collection site.
We set a new and slightly optimistic target of 396 collections, from the 37 different Myrtaceae species spread nationwide. We were no longer focusing on just the North and upper South Island. Our seed collecting now ranged from Raoul Island in the Kermadecs down to Auckland Island in the Antipodes.
Our work this year
Going into the third round of seed collecting at the start of this year, we knew we now had the staff and the skills needed to streamline the process of collection, which was now a necessity considering the extreme nature of collecting certain seed. Take northern rata. It’s one species where you can’t collect seed from the ground. You need a trusted helicopter pilot, a person on a sling, a spotter/recorder and a plant specialist to confirm the tree species and check for myrtle rust. Round 3, which ended in August 2018, was another success.
With all the hard work of over 70 collectors including staff, volunteers, iwi and private land owners, out of our optimistic target of 396 collections, we are well over half way (57%) – with only 166 collections to go.
We’ve completed the collections of 7 species already. So far more than 60 million Myrtaceae seeds have been collected for long term storage. This has been a fantastic effort from everyone involved. When we first started collecting in May 2017 it was all a bit manic. We had never collected seed from these species before. We had very little knowledge about when Myrtaceae fruit are ripe, and most staff were not trained in seed collecting. Staff also had to fit scoping, permissions and collecting into their busy schedule.
We set ourselves an ambitious target, and despite the early challenges, we have made huge inroads in reaching it already. A special thanks must be given for all of those who have contributed their time to make this happen. There’s still more work to do to reach our target, and planning and training for the next round is already underway. Our seed collection work will begin in January and run to June next year.
One would hope that effort is being made to collect seed from species that may have evolved resistance to the disease.