Myrtle rust spread 'has potential to change landscape'
A widespread outbreak of myrtle rust disease had the potential to dramatically change the treescape of the region.
The long term effects of the windborne fungal disease, which has so far affected five horticultural properties nationwide, including three in Taranaki, are unknown.
The disease affects the myrtaceae family including 3000 species, among them pohutukawa, rata, feijoa, ramarama and manuka, and various garden ornamentals.
The Taranaki landscape would be altered if large tracts of pohutukawa and manuka were destroyed by the disease, said gardening writer, Glyn Church.
* Highly contagious myrtle rust plant disease found in Taranaki
* Potentially devastating myrtle rust found at Taranaki nursery
* Myrtle rust spreads to five properties in Northland and Taranaki
"We could see 1000's of pohutukawa trees dying in front of our eyes," Church said.
"The myrtaceae family is quite large, it includes eucalypts, and the outcome of the disease is not known.
"It could wipe out the trees, or it could make the plant weaker but not really kill them off.
"One thing we are certain of is that is here and would be impossible to get rid of."
Church said plants grown in warmer climates were often more susceptible to the disease than colder climates.
"We've seen this in Australia where the disease has spread further northward along the eastern coast than southward.
"The warmer the temperature the worst effect it had on the plants."
Church said containing the disease might be the best solution.
"Trying to spray huge tracts of hillside would be very expensive and probably not effective.
Taranaki public gardens such as Pukeiti, Hollards and Tupare, would be prone to an large scale outbreak of myrtle rust.
So to would large numbers of pohutukawa which line Taranaki roads and streets, Church said.
Both Taranaki Regional Council and New Plymouth District Council were making daily checks on whether the disease was among the vegetation in the parks.
Regional council operations manager Stephen Hall said the council could not speculate on the potential effects of myrtle rust for Taranaki, or possible effects on the Taranaki Regional Council gardens.
Both council's would follow the advice from lead agency MPI.
New Zealand First leader Winston Peters has called for the resignation of Primary Industries minister Nathan Guy.
"The further discoveries of myrtle rust in New Plymouth, along with the original Kerikeri nursery, are failures in biosecurity that the Minister must now take responsibility for," Peters said.
"Minister Guy's position is untenable,"he said.
"We are angry about this because the minister has not taken myrtle rust seriously, neither when NZ First raised it in Parliament over a month ago, nor when he failed to make a ministerial statement when he knew it had got to Northland.'
Peters said the Parliamentary Commissioner for the Environment, Dr Jan Wright, should be asked to commence an independent investigation into how myrtle rust arrived in New Zealand.
Scion, in a report produced only last year, restated its view that the biggest risk to New Zealand was from imported plant material and daily they are being proven right, he said.
Ministry for Primary Industries have 50 staff working on the ground in Taranaki identifying further outbreaks of the disease.
Regional controller Mark Bateman said people should call MPI hotline 0800 80 99 66 if they see any suspicious symptoms of the disease on plants.
Do not touch the rust, or the plant but note the location and take photos of the symptoms and the plant, he said.
- Taranaki Daily News