Potato Review

32 POTATO REVIEW JULY/AUGUST 2021 LATE BLIGHT A S Hutton Criteria disease warnings were declared in key potato- growing areas, growers have been urged to take urgent action to protect potato crops against late blight. Planting was delayed in many regions following a cold first quarter, so a significant proportion of crops were still in the rapid growth phase as the threat of disease climbed higher. e AHDB’s BlightSpy tool indicated a move into the highest threat level for many counties over a 48-hour period in June, and growers across the east, south-east and south-west of England were on BlightSpy red alert, along with farmers across the whole of Wales and South West Scotland. Craig Chisholm, Field Technical Manager with Corteva Agriscience, said regionally some crops had emerged slowly and steadily and were expected to “dash on” in the warmer weather. He recommended using two applications of Zorvec Endavia in the rapid ‘Take action now’ Vigilance urged as weather threatens to increase potato blight disease risk. growth phase, providing a base on which to build a robust programme. “Now is the time to ensure those bene ts conferred by Zorvec are deployed in your blight programme so your crop gets o to the cleanest possible start,” said Craig. “ is will make managing blight easier across the remainder of the season. Corteva’s oxathiapiprolin-based chemistry has been instrumental in meeting growers’ needs to get a start clean, providing protection for 10 days, meaning if weather prevents sprayers from travelling, or capacity restricts visits to more distant crops, they will still be protected. In addition, its curative properties also deliver kickback on any latent disease in the crop, he said. Craig said: “Even as late blight becomes increasingly aggressive and resistance or reduced sensitivity to some actives becomes more common, Zorvec applied at the rapid growth phase will deliver lasting protection through exceptional curative and protectant activity on stem and foliar blight.” Once an infection is present the cost of trying to keep it under control is considerable. erefore, opting for a product and programme which is more e ective early in the season will save money in the longer term. “With up to four applications of Zorvec permitted on the potato crop, growers still retain the exibility for one to two applications during the stable canopy when disease pressure and spray interval pressure may increase further,” he said. Vigilance urged as weather threatens to increase potato blight disease risk.msg