Mrytle rust on the flower
Staff and students are being asked to help fight an outbreak of myrtle rust tree disease on the Mt Albert campus and in their wider communities.
Myrtle rust is a serious fungal disease that attacks plants in the myrtle family, which includes New Zealand’s native pōhutukawa, mānuka, rātā, and common ornamental garden plants like bottlebrush and lilly pilly. The disease spreads by spores that become windborne or are carried by honeybees.
It was first detected in Aotearoa/New Zealand in May 2017 and is now widely distributed across the country. As a precautionary measure, Associate Professor Dr Peter de Lange from the School of Environmental & Animal Sciences started monthly monitoring of myrtles on campus, including two maire tawake (an indigenous myrtle) growing on the margins of Te Wai Unuroa for signs of the disease.
Unfortunately, on 23 January Wendy Johns, co-ordinator of the Te Auanga / Oakley Creek Restoration team, found myrtle rust on one of the trees. This was confirmed by Dr de Lange and the trees have now been removed as they were so seriously infected that their abundant spores, pose a threat to other myrtles on the campus and the wider community.
Peter de Lange
“I am sad to see those trees go,” says Peter. “They were beautiful specimens that added grace to the wahi tapu puna, and we cannot replant that species on campus for the foreseeable future.”
“Sadly, myrtle rust poses a serious threat to myrtles throughout the country and as there is no cure, our myrtles are going to get sicker and we may even lose some species or genera,” he says. Species under threat include ramarama, rohutu and several of our rata vines. Disturbingly, pōhutukawa at Tairawhiti / East Cape are also succumbing.”
There are 28 species of myrtle in New Zealand, and these are critical for forest succession, providing important food for animals and a raft of habitats for other plants and fungi, many of which are endemic to the myrtles.
“We are not just seeing the potential for numerous sick myrtle trees, shrubs and vines, we may also lose entire associated ecosystems,” he says.
Although the outlook may seem bleak, we can all help slow and prevent its spread to preserve our beautiful pōhutukawa and rāta blossoms, mānuka honey and rongoā, and the cheer of Christmas flowering kanuka, he says.
If you have lilly pilly hedges or plants, consider removing them as myrtle rust is highly attracted to it and having it on your property creates a reservoir for future infection and spread. Other measures include not planting that species and encouraging others not to do so.
Finally, be vigilant, if you see suspected myrtle rust, take good photos of it and its host. You can post these on iNaturalist NZ https://inaturalist.nz/ as your observations will help the many researchers out there trying to slow the spread and find a cure for myrtle rust.
If you notice any myrtle rust on the Mt Albert Campus, please take a photo, note the locations and please email Peter
More information about myrtle rust can also be found here .