The scale of the Potato Mop-Top Virus (PMTV) problem on New Zealand South Island potato farms has widened.

Eighteen Canterbury farms are now on the suspect list, after the virus was first found on two properties last month.

Extensive testing ongoing

So far, 2986 tubers have been tested for Potato Mop-Top Virus, of which there are 33 positive samples, 30 of variety Innovator and 3 of variety Russet Burbank.

The positive tubers are linked to twenty properties, however the properties of origin is still to be confirmed. All samples are from the previous growing season.

Biosecurity New Zealand has also started testing potatoes from North Island growers.

Seedline testing

Seedlines for the current 2018/2019 season are being tested and are all negative so far.

Testing of the Innovator, Russett Burbank and Agria seedlines is complete and are all negative.

Sampling for Nadine (2018/2019) seed lines and Moonlight seed lines is still ongoing.

Current objectives

The main focus at the current time is to understand the risks associated with the possible establishment of PMTV in New Zealand, and to minimize its impact. Investigative work is underway to:

• Understand virus distribution and impacted crops to formulate options to manage, contain or eradicate
• Delimit and contain infection on known paddocks and processing plants, particularly focusing on processing waste contamination
• Inform affected stakeholders of potential issues while maintaining minimal alarm within the industry and in the public
• Minimise impacts to exportable potatoes and potato products to relevant trade markets
• Determine if import pathway can be identified
• Engage with industry partners and stakeholders, and work with them to effectively manage the response

(Click to access)

Click to access Potato Mop-Top virus factsheet
Courtesy: Biosecurity New Zealand, September 2018)