Blackleg in potatoes: Rapid and effective haulm destruction key to blackleg control

Although the exact origin of the bacteria that causes blackleg hasn’t yet been pinpointed, they get into the soil and appear to multiply on plant roots.Scientists are getting closer to discovering the origins of blackleg infection in potato seed crops. CPM magazine finds out the latest research findings and how Scottish seed growers are acting on them. Over the past few seasons, blackleg has been the thorn in the side of Scottish seed producers, with the disease now the number one reason for down-grading or failure of seed stocks. The inevitable question is ‘why is this happening?’, says Prof Ian Toth, research theme leader at the James Hutton Institute. To try and understand the issue, AHDB Potatoes and SASA jointly funded a three-year project to identify the routes of blackleg contamination. The point where levels of the bacteria responsible for blackleg, Pectobacterium atrosepticum (Pba), reached their highest levels coincided with haulm desiccation, which indicated that the method of haulm destruction may have a critical bearing on the potential levels of blackleg infection, Toth says. Eric Anderson, senior agronomist for Scottish Agronomy, has long held the belief that speed of haulm death is of critical importance when it comes to minimising contamination by blackleg. More