General biosecurity direction issued in effort to combat potato mop-top virus

New biosecurity rules are in place for potato growers to help stop the spread of mop-top virus.

On Friday, Biosecurity Tasmania’s Chief Plant Protection Officer, Susanna Driessen, issued a general biosecurity direction.

The requirements in the direction include ensuring that equipment used for the production, harvesting, transport, or processing of potatoes is cleaned and free of soil; that any plants suspected of having mop-top are destroyed; and that growers keep records of planting, harvest, and supply for at least three years.

Growers must also provide written notice to buyers if their potatoes may be carriers of mop-top.

The biosecurity direction will be in place until June 2027.

Mop-top virus was first detected on a Tasmanian farm in July.

It was the first time it had been detected in Australia, but traceback work indicated the virus could have been present in Tasmania for two years.

Authorities have since determined that eradication of mop-top was not feasible and have shifted the focus to long-term management of the virus.

Mop-top is carried and transmitted by Spongospora subterranea, a soil-borne pathogen that causes powdery scab in potatoes.

There are no human health risks associated with consuming potatoes that have the virus or powdery scab.

Spuds that have the virus can display both foliar (leaf) and tuber symptoms of varying severity depending on the sensitivity of the variety and the source of infection, which include distortions to the skin; deep cracking, and rust-coloured arcs, streaks or flecks in the tuber flesh; and yellow colouration on the leaves.