Potato Review

www.potatoreview.com POTATO REVIEW MAY/JUNE 2022 15 BLACKLEG I f all risk factors align, applying a harpin-based foliar biostimulant product to potato crops early in development could minimise disease progression later in the season. Blackleg is a big worry for the British potato industry, causing significant losses when seasonal conditions favour its development. It is caused by several pectolytic bacteria capable of infecting and breaking down plant tissue. Across England, Wales and Scotland, Could a protein-based biostimulant help tackle blackleg? Interest in crop biostimulants is increasing and there are a now lots of manufacturers making bold claims about their respective products. Potato Review looks at the performance of one harpin protein-based material that might help suppress blackleg. most cases are caused by Pectobacterium atrosepticum (Pba), according to data gathered by FERA and SASA. Symptoms range from a mild wilting of plants, through the complete necrosis at the stem base, causing the tell-tale rotten stem or “blackleg”. Progeny tubers are also impacted, with bacteria able to move into the flesh via stolons or through lenticels, leading to soft rotting. Soft rots can be problematic, as rotten tubers spread inoculum during the handling process and trigger costly break downs in store. Sources of infection include infected seed and soil, irrigation water, bacterial aerosols, insects, weed hosts and more recently, free-living nematodes have been implicated in its transmission. Researchers still have questions about the epidemiology of blackleg in potatoes and it remains relatively difficult to predict exactly where and when problems may arise. This makes it equally difficult to test