A ramarama plant infected with myrtle rust. PHOTO/MPI
BECKIE WILSON
The vicious fungal plant disease that is spreading into many North Island regions could already be lingering in Wairarapa undetected, says the Ministry of Primary Industries’ (MPI).
Myrtle rust is a disease that affects plants and trees in the myrtle family such as pohutukawa, ramarama and rata.
In September last year, MPI ruled out feijoa being at risk of contracting the disease.
Several owners of local nurseries and beekeepers admit that it is very likely that it is not a question of id, but when, the disease will be found here given that surrounding regions.
Wairarapa sits in between two regions that have detected the disease, Wellington and Manawatu.
The disease was first found in Wellington in December last year, and more recently it was detected along the Victoria Esplanade in Palmerston North on Monday.
First spotting in May, in Kerikeri, Northland, the disease spread to Auckland, Waikato, Bay of Plenty and Taranaki in ensuing months.
It was found in garden nurseries, a golf course, private gardens, an orchard, a school and on public conservation land.
The ministry’s myrtle rust response spokesperson Dr Catherine Duthie said Wairarapa was classified with a low-to-moderate risk of contracting the plant disease because of its climate and presence of fewer myrtle plants.
However, as spores from nearby regions disperse, Wairarapa could be at higher risk over time, she said.
“It is possible that it is present and undetected, so we encourage residents to check the myrtles in their gardens,” Dr Duthie said.
In the early stages of the myrtle rust response, MPI commissioned NIWA to study the climatic conditions where the disease thrived.
Most of the North Island was identified as being at high risk, excluding western Manawatu and Wellington regions.
“The earlier we find an infection, the better our chance of containing it and slowing its spread into unaffected areas.”
Norfolk Rd Nursery owner Evan Hooper said it was “probably inevitable” the plant disease would arrive in Wairarapa.
In Mr Hooper’s nursery, the plants that would be under threat are rata, manuka and ramarama.
While he was unsure if the manuka plants would be badly effected by the disease, his concerns lay with the rata tree.
“[Ratas] are getting less common up in the bush and no one plants them much which is a shame — once they are dead they’re dead.”
The disease could easily arrive by people from Wairarapa buying plants from effected regions then bringing them to the region, he said.
Manuka Health’s general manager of Apiculture Dave Campbell believed it was likely Wairarapa would see the plant disease but beekeepers were well aware of their responsibilities, he said.
Ministry statistics show that only one manuka plant out of more than 11,500 inspected by itsofficers had been infected by rust.
“This is the lowest prevalence of all New Zealand species surveyed.”
Despite these figures, the company was strictly following MPI’s guidelines, he said.
Manuka Health has a multi-million-dollar factory in Carterton which expanded last year.
“The evidence to date suggests [myrtle rust] is unlikely to pose a significant risk to manuka, but it’s early days so we still want to be very cautious.”
Wairarapa Department of Conservation ranger Jim Flack said the department’s primary response to the plant disease was seed collection as insurance against any extinction of species.
The department is into it’s second year of seed collection of the myrtle family plants.
Seeds are then sent to the New Zealand Indigenous Seed Bank in Palmerston North.
Mr Flack said this was done in each region — the Wairarapa rata was different to rata grown in other regions, so seed collection was important.
Rata was an iconic in the Wairarapa bush found in places such as the Tararua Ranges and Pukaha Mt Bruce.
“That would be a massive blow if northern rata was [killed off],” Mr Flack said.
DOC officers do regular surveillance when out and about on the species at threat.
In terms of the ramarama species, there are a couple of spots in Masterton that staff are keeping an eye on, he said.
