Potato Review

40 POTATO REVIEW JULY/AUGUST 2021 BLIGHT A SPECIALIST agronomist, a grower and a crop protection manufacturer shared their best-practice advice for blight control now and in the future. Together with his business partner at Spud Agronomy, John Sarup, is responsible for more than 11,000 acres of potatoes across Northern England up to the Scottish Borders. “Getting to the source of the inoculum is key,” he said. “Usually that’s about controlling volunteers, and growth on potato dumps. With the loss of CIPC, we’re turning to maleic hydroxide, a sprout suppressant, which is an e ective active for controlling volunteers. “ e next step is understanding which genotypes you’re dealing with. As soon as blight appears in your crop, take a sample and send it in via the ‘Fight again Blight’ initiative. It will help you make informed decisions about what products you can use safely without causing any resistance issues.” Despite the delayed start to this year’s season, AHDB has already recorded the rst incidence of 2021. Several patches of the disease were seen in a crop of Maris Peer in Kent when the sample was collected on May 26th. Overall, John describes the current pressure further north as ‘low’. “Soils have been so cold and wet that generally speaking, we’re two to three weeks behind. Crops are now growing very quickly but they are dry. Even at night there doesn’t seem to be too much leaf wetness. I’ve some early crops in Cheshire which have relatively large canopies at 50% ground cover and we’ve started applications. Currently it’s about preventing the development of blight, but as the crop moves Understand the genotypes and follow strict timelines Agronomist and grower share their best practice advice on blight “I’ve some early crops in Cheshire which have relatively large canopies at 50% ground cover and we’ve started applications.” John Sarup, agronomist into rapid growth stage, that’s when we’ll start with products that protect the growing point.” John adapts fungicide programmes based on a variety factors, including product performance and cost. “You’ve got to look at the strengths and weaknesses of products and use products when they are likely to be most e ective. For example, some perform well on tuber blight and are e ective Agronomist John Sarup is jointly responsible for more than 11,000 acres of potatoes across Northern England up to the Scottish borders. Grower James Porter has 100 acres of potatoes at East Scryne Farm in Angus. Blight leaf lesion. AHDB has already recorded the first blight incidence of 2021.