Biosecurity teams are scouring Kerikeri nurseries after the detection of myrtle rust, a significant disease which threatens plant varieties important to the honey industry, such as manuka and kanuka, and $300 million of annual honey exports.
Feijoa, gum and bottlebrush trees are also threatened along with some treasured indigenous species such as pohutakawa and rata.
Primary Industries Minister Nathan Guy said authorities were notified on Tuesday evening of a nursery in Kerikeri where pohutakawa seedlings had suspected myrtle rust.
Laboratory testing has since confirmed the disease.
The Ministry for Primary Industries has initiated a Restricted Place notice to restrict the movement of any plants and people at the site, and is treating nursery stock with fungicide spray as a precaution, Guy said.
Work was also under way to trace any stock that had left the nursery and all other nurseries in Kerikeri were being inspected today.
According to the Northern Advocate (HERE), the disease is prevalent in eastern Australia and Tasmania, and was discovered on Raoul Island in late March this year.
Officials believe wind is the likely pathway of incursion into Raoul Island, and it is likely that wind has carried spores to mainland New Zealand from Australia.
Conservation Minister Maggie Barry acknowledged the incursion could have serious consequences for some native species.
“Myrtle rust generally attacks soft new leaf growth, and severe infestations can kill affected plants,” Barry said.
“This could include native species like the pohutakawa and the rata.”
In Australia, the fungus has caused the extinction of several treasured plant species of significance to Aboriginal Australians.
“Myrtle rust has long been expected to arrive in New Zealand, and since the Australian outbreak began in 2010, the Government has worked on a range of measures to help manage and adapt to the fungus in the long term if necessary,” Barry said.
“This includes accelerating work already underway to collect and store germplasm from affected species, searching for signs of resistant myrtle strains which could be incorporated into a breeding programme and monitoring at 800 locations across the country.”
The Department of Conservation would also be conducting inspections of myrtle species on public conservation land in Northland for any early signs of the fungus.
There is no known method of controlling the disease in the wild, apart from applications of fungicide in very small areas as a last resort.
Even if eradication is achieved, there was an ongoing risk of reinfection from Australia.
Anyone believing they have seen myrtle rust on plants in New Zealand were asked to call MPI on 0800 80 99 66.