Myrtle rust outbreak in the Western Bay of Plenty - hundreds of sightings reported

Myrtle rust has been discovered in hundreds of locations in the Western Bay of Plenty. Photo / NZME

Clusters of myrtle rust have been found throughout the Western Bay of Plenty, with Ōmokoroa, Te Puke, Bethlehem and Mauao appearing to be the worst-hit areas.

The infectious, airborne fungus has the potential to damage many ecologically, economically and culturally significant tree species including pōhutukawa, rata and mānuka, which are members of the myrtle family.

Ministry of Primary Industries surveillance shows hundreds of sites through the Western Bay region, including Welcome Bay, Pāpāmoa, Mount Maunganui, Greerton, Pyes Pa, Waipuna and Katikati where myrtle rust has been found.

But the most prevalent sightings of myrtle rust were in Te Puke, Ōmokoroa and Bethlehem.

Council environment team leader Paul Greenshields told the Bay of Plenty Times the council was also aware of a “small-scale infection” in the Waikareao West Reserve by Goods Rd “and much larger scale of infection in several areas on Mauao”.

“There’re currently no reserves, tracks or walkways closures due to myrtle rust. If we do need to activate closures, we’ll ensure the community is aware beforehand.”

Earlier this month, Tauranga City Council confirmed myrtle rust had been found on a large scale on Mauao. Myrtle rust was first discovered on Mauao on February 2022 but on a smaller scale.

Greenshields said its monitoring of the disease on council land and reserves was reactive “with the exception of Mauao”.

“Essentially when we find myrtle rust on council land/reserves, we report it to the Ministry of Primary Industries who is the lead agency on the management of myrtle rust,” he said.

“Once identified, we follow MPI’s guidance for monitoring and control of the diseased trees. One of the ways we manage the spread is planting trees that are less susceptible to the disease.”

Greenshields said the council could not do this on its own and called on people who may find myrtle rust on council and or reserves to follow the guidelines set out by the ministry - don’t touch it, take a photo and submit the photo online.

Western Bay of Plenty District Council reserves and facilities manager Peter Watson said it was only actively monitoring Waitui Reserve at this stage “but we know there are numerous sites in Katikati that are showing signs of myrtle rust on pōhutukawa and other affected species”.

Watson said the council has not yet had to close any reserves or removed any plants because of myrtle rust.

“Because wind is such a big factor in spreading myrtle rust, it is very difficult to control its spread.”

Watson also asked people who find myrtle rust to follow the guidelines and report it.

Myrtle rust spores are microscopic and travel large distances by wind, or by insects, birds, and people. It is believed that wind carried spores here from Australia, after it was first found there in 2010.

The fungus has spread rapidly since the first case in New Zealand was identified in 2017.

If people suspect they have found the disease, they should not touch it, take a clear photograph and submit it to the iNaturalist website, via the Ministry of Primary Industries, with details about the plant it was found on. This can help experts confirm if it is myrtle rust.