Potato mop-top virus (PMTV) was recently detected in Northwest Tasmania, marking Australia's first encounter with the pathogen. For New Zealand growers, the detection serves as a reminder of the importance of continued vigilance against an existing but well-managed threat.
PMTV was first identified in New Zealand in September 2018, when a potato processing facility detected symptoms in tubers during a load inspection. Eradication was not possible, but long-term management has proven effective. Industry-led initiatives supported by Biosecurity New Zealand have ensured the virus remains a pathogen of low significance for local production.
© Potatoes New Zealand
The virus causes characteristic defects in potato tubers, including rust-coloured arcs, cracking of flesh, and necrosis. It does not pose any food safety risk, but it can affect crop yields and processing quality if unmanaged. PMTV is spread through Spongospora subterranea, the soil-borne pathogen responsible for powdery scab, and can survive in soil for more than 12 years.
New Zealand's approach has relied on several strategies. The industry strengthened seed potato health requirements, provided growers with identification guides, and carried out routine surveillance testing. Long crop rotations and existing powdery scab management practices have also helped restrict the virus's spread.
Canterbury, the country's main seed potato production area, was initially considered most at risk of dissemination. Coordinated measures from Potatoes New Zealand, the Ministry for Primary Industries, and processing companies such as McCain Foods supported containment and management efforts.
Ongoing surveillance indicates PMTV remains present but at very low levels, particularly in processing crops. While the pathogen continues to appear in harvested potatoes, current management protocols ensure it does not present a major risk to productivity or profitability.
For more information:
Potatoes New Zealand
Tel: +64 (0) 800 399 674
Email: [email protected]
www.potatoesnz.co.nz