By Beckie Wilson
Wairarapa’s at-risk industries such are bracing for the arrival of the vicious myrtle rust fungal plant disease with the number of North Island sites affected by disease increasing steadily.
Myrtle rust is a disease that affects plants and trees in the myrtle family, and has been found on pohutukawa, ramarama, eucalyptus and manuka plants.
Since the beginning of May, the disease has been detected at 34 sites – 29 in Taranaki, three in Northland and two in Waikato. The sites include private gardens, plant nurseries and orchards.
MPI myrtle rust response incident controller David Yard said it is possible that it could reach Wairarapa if there was a big enough outbreak of it elsewhere in the country.
“The most suitable climate for myrtle rust is in the north of the country but science tells us it could survive in the lower North Island and parts of the upper South Island,” he said.
MPI is monitoring the disease which it believes entered the country by wind from the eastern seaboard of Australia where it is well established.
The manuka honey industry could be most at threat for Wairarapa, including local nurseries, and once detected, the spores can spread by clothing, equipment and wildlife.
Mr Yard said it was a different situation to the pea weevil outbreak last April.
Pea weevil is an insect that can be treated with insecticide, however myrtle rust is an airborne fungus which is difficult to treat – “in fact myrtle rust has never been successfully eradicated anywhere”.
Clareville Nursery owner Steven Portman is not taking any risks when it comes to the threat of myrtle rust. They have a staff member dedicated to monitoring the susceptible plants, and has stopped sourcing any at-risk plants from across the country.
Its way of monitoring meant they were more likely to detect the disease early rather than in the open environment, he said.
“Who knows if it will spread more widely and this is the tip of the iceberg, or if we are onto it and MPI have got it covered,” he said.
He asked that people who have fund the disease in their home garden not to bring it into a garden centre, and to bring in a photo instead.
Manuka Health New Zealand CEO John Kippenberger said he had been following the spread of the disease with “strong concern”, but said it is still early days to predict the potential effects on manuka plants.
The beehives were hibernating now and no changes had been made in the running of the hives.
New Zealand’s manuka honey exports were worth NZ$315 million in the year to June last year, Ministry of Primary Industry figures show.
The product fetches as much as NZ$148 per kilogram, government figures show.
Mr Kippenberger said reports from Australia showed that “it had very limited impact” on manuka honey production there.
“It is too early to speculate what it could be. We are hoping it will behave similarly to how it was to Australia.”
The industry is still trying to understand it, but “the jury is out and will be for a while”.
Gardening guru Gareth Winter said vigilance is key for all those with private gardens. The disease is most likely to affect young plants as they are not as hardy as older plants.
“ . . . the reality is that I’m not sure that we will be able to stop it spreading,” Mr Winter said, adding that he did not think the spread and impact of myrtle rust would be as significant as pea weevil.
