Myrtle rust keeps spreading with new finds in city
Four new cases of myrtle rust have been found in Nelson city.
The new sites were discovered last week at private properties in The Wood and on public land in Tahunanui.
It follows a previous find two weeks ago of myrtle rust on ramarama and po¯ hutukawa trees in and around the city.
A Ministry of Primary Industries (MPI) spokesperson said a decision on the management of myrtle rust would be announced next week. The airborne disease has spread from the North Island, and was found in the South Island in Collingwood earlier this year.
The MPI spokesperson said a scientific paper published this year predicting the climatic risk of myrtle rust during its first year in New Zealand showed Nelson had a ‘‘moderate to high’’ risk of developing infections.
The infection risk and impact depended on a combination of suitable climatic conditions, host availability and host susceptibility, and could vary over time depending on those factors.
Myrtle rust affects plants in the myrtle family, which includes po¯hutukawa, ma¯nuka, ra¯ta¯, ka¯nuka, swamp maire and ramarama, as well as commercially-grown species such as eucalyptus, feijoa and New Zealand cranberry. The spores are thought to have crossed the Tasman Sea on wind currents.
Over the long term, 10 to 20 years, myrtle rust could affect iconic New Zealand plants as well as commercially-grown species. Severe infections could kill affected susceptible plants and have long-term impacts on the regeneration of young plants and seedlings.
The total number of infected properties in New Zealand is 769.