Dry rot risk is high in Scotland this year and seed potato growers are being urged to apply tuber treatments as early as possible to prevent disease progression in store.
It has been a relatively easy potato growing season in Scotland in 2021, but its benign nature has brought its own set of challenges as the main harvest period approaches. High tuber dry matter levels and warm and dry soils across the majority of the potato growing areas means that risk of bruising and damage during harvest will be high. In turn, this will increase the chances of disease ingress into tubers and in particular, Fusarium spp. which causes dry rot.
Scottish Agronomy’s Eric Anderson advised growers must plan to mitigate the risk of physical tuber damage and dry rot infection and development, starting during the harvest process. He said primary harvester webs must be kept full of soil during lifting, reducing nicks and scrapes, and watering kits should be used to lubricate haulm rollers where available.
Once in store, positive ventilation should be used immediately to cure and cool seed crops to holding temperatures. It is then wise to consider a seed tuber treatment like Gavel (imazalil), which offer good protectant activity against the Fusarium species that cause dry rots. “Because the fungicides we have are protectant, it should be applied as soon as possible to reduce the risk of losses later in the year,” added Mr Anderson. Certis technical specialist Harry Raley reminds growers that seed tuber treatments like Gavel cannot be applied to potatoes destined for the human or animal food chain. “Ideally, seed crops should be split graded into seed size fractions before application of Gavel over a correctly calibrated roller table. “This will give optimal coverage of tubers and allow growers to maximise income by selling any untreated “tops” as ware.”
Picture Caption: Eric Anderson