Potato crops around the UK are entering the highest threat level for blight.

Hutton Criteria disease warnings were declared in key potato-growing areas, as the AHDB’s BlightSpy tool put growers across the East, South East and South West of England, the whole of Wales and South West Scotland on alert.

A Hutton Criteria period occurs after two consecutive days with a minimum temperature of 10°C and at least six hours of relative humidity (90%). It is used for blight risk reporting to help to support decisions, refine action plans and empower growers against blight.

Planting was delayed in many regions following a cold first quarter, so a significant proportion of crops are in the rapid growth phase as the threat of disease climbs higher.

Speaking from crop protection company Corteva, Craig Chisholm, commented that this was the time for growers to spray for blight to crop get their crop off to the cleanest possible start.

“This will make managing blight easier across the remainder of the season," said Mr Chisholm. “Regionally some crops have emerged slowly and steadily and will now be expected to dash on in the warmer weather. Two applications of Zorvec at the rapid growth phase should be a structural part of most programmes given the current conditions."

He warned that once a blight infection is present, the cost of trying to keep it under control is considerable – so opting for a product and programme which is more effective early in the season will save money in the longer term.