Watch black dot, says BPC

Potato growers have been advised to be on the look-out for the skin disease black dot as stores are filled. Latest results from monitoring work undertaken by the British Potato Council (BPC) indicate levels of the disease are high.

"The pathogen thrives in warm and wet conditions in the field," notes Jeff Peters from Sutton Bridge Experimental Unit (SBEU). "Despite relatively cool weather, we thought it was going to be a bad year because of the wet soils, and latest results of test crops have confirmed this."

Trial crops lifted in mid-October from fields with high inoculum levels in the soil had 12-14% average tuber surface area affected by black dot, he reports. "At current levels, which are similar to last year's high severity, some crops will face rejection, unless action is taken."

The longer the crop is in the ground, the greater the chance of the disease developing, explains Dr Peters. "Late-harvested crops will be at risk. The symptoms develop in store, so a dry crop and a fast pull-down of store temperature are important to keep levels low. Monitoring crop quality throughout the season is vital to ensure there are no nasty surprises."