RECENT FULL label approval for Amistar (azoxystrobin) against soil-borne rhizoctonia and black dot gives potato growers a new weapon in the fight against disease, says Syngenta.

Amistar is the first available treatment for soil-borne rhizoctonia, the company says. Before the changes it could only be used against black dot under Specific Off Label Approval.

“Skin quality issues alone cost UK potato growers an estimated 7m a year,” says the firm”s Garth Bretherton.

“Black dot and rhizoctonia reduce marketable yield and seriously affect storability.”

Rhizoctonia stem canker affected 72% of crops in a recent DEFRA survey, with black scurf and black dot affecting 59% and 56%, respectively, he notes.

“Reducing the initial level of soil-borne rhizoctonia infection minimises early pruning effects and can help to achieve even crop emergence. That makes all subsequent management easier.”