PESTS AND DISEASES The North American potato industry is ramping up efforts to contain the blackleg-causing pathogen that’s caused significant crop losses in the U.S. in recent years. DEFENDING AGAINST DICKEYA P by Mark Halsall otato industry stakeholders from across the United States gathered in Bangor, Maine in November 2017 to deliberate on Dickeya, the aggressive disease that’s devastated thousands of potato acres in the U.S. since its first major outbreak in 2015. Sponsored by the University of Maine Cooperative Extension, the one-day summit drew more than 160 seed potato growers and buyers, research scientists, and other industry representatives, all eager to hear about the latest developments in the fight against Dickeya. Topics covered included the current Dickeya situation in U.S. and Europe, emerging Dickeya species, the latest advances in detection of the disease, and the needs of future Dickeya research. The conference also focused on new strains of Pectobacterium, another pathogen in the blackleg complex that’s become a growing cause for concern for potato producers in the U.S. Gary Secor, a plant pathologist from North Dakota State University (NDSU) and one of the organizers of the event, says the conference was a big success. “It exceeded all of our expectations for attendance and content,” he says. Dickeya discussions have dominated the potato meetings circuit in both the U.S. and Canada the past couple of years as the North American potato industry looks for ways to contain the disease. A bacterial pathogen that’s been affecting potatoes in Europe since the 1970s, Dickeya can be transmitted over long distances and across national borders through infected plant material, which can include other vegetables and some ornamental plants. The disease is now found in numerous potato producing areas in the U.S., particularly in Maine and other states along the eastern seaboard. Because Dickeya in potatoes is primarily spread through infected seed, a growing number of seed growers and buyers are choosing to test potato seed lots for the pathogen. Secor says the consensus among attendees at the recent Dickeya conference was that the amount of Dickeya found in seed and commercial potato fields in the U.S. appeared to be down in 2017, compared to 2016. ABOVE: A potato plant killed by Dickeya. 12 TOP CROP MANAGER/POTATOES IN CANADA | Spring 2018 PHOTO COURTESY OF STEVE JOHNSON.