All are in Canterbury but PotatoesNZ is going nationwide to test for the virus.
With eradication deemed a no-go for the virus the industry is now working towards long-term management of the disease.
“On that basis we are moving to long-term management and there are a series of steps we need to take to do that and we are in that process now,” a Potatoes NZ spokeswoman said.
“In long-term management there are a number of options we can look to take and we are working through those.”
Biosecurity NZ and PotatoesNZ are working together on what the management programme will look like.
PotatoesNZ will consult growers, the wider industry and other interested parties.
“To assist with some of this work we have welcomed a new technical assistant team member who is tasked with doing surveillance on potato mop top virus and to work in the field with farmers as we undertake greater surveying around the country.”
The potato industry is starting to test tubers for the virus in the North Island.
“It very much looks like potato mop top virus is contained in Canterbury but we need to check.”
It is still unknown how the virus got to NZ.
“And as is the case with most of these biosecurity incursions, the Ministry for Primary Industries never finds the source as it’s very difficult to track.”
PotatoesNZ is evaluating whether a pest management plan will be a suitable method to prevent the further spread.
To establish that the industry body will consult growers, the wider industry and other interested parties.
As the positive results have been found in Canterbury the work will initially be focused on Canterbury with technical workshops also planned for Pukekohe, NZ’s other main potato growing area.
The virus is transmitted by the soil-borne fungus that causes powdery scab (Spongospora subterranea) and can survive long-term only in the potato plant or in the fungus.
Once established in fields the virus can survive in the fungus for up to 20 years.
The infection can be either directly from the infected mother tuber or by a powdery scab infection of the roots.
Specific on-farm management measures include not growing potatoes in affected paddocks, cleaning and disinfecting equipment, machinery and vehicles to avoid spreading soil between paddocks and properties and using signs to ensure workers and visitors are aware of biosecurity hygiene practices.
The virus is a notifiable organism under the Biosecurity Act.
It is not a food safety issue and people can trust potatoes to eat. It is manageable if it becomes established.
The disease is established in North America and Europe where it is generally managed effectively without causing major production losses but where it is poorly managed it can create production problems.
If growers suspect they have found the virus they should contact the BiosecurityNZ pests and diseases hotline on 0800 80 99 66.
