b'Potato earlydying complex is an economically devastating disease Canadianpotato growers faceeach year.PHOTO: TUDOR BORZAPEDS PRESENCE IN CANADA was also found to have a higher incidence in fields used to grow potatoes in com-It was the fall of 2013 when Borza first got involved with projects related toparison with fields used to grow strawberries, regardless of rotation practices. Verticillium wilt and PED in eastern Canada. Initially, most of the work was carriedSince 2018, Borza has also been responsible for a New Brunswick-based out in Prince Edward Island and Nova Scotia, while molecular testing was done inproject on the status of PED and best management practices in the province. the laboratory of Gefu Wang-Pruski, a professor and potato researcher at DalhousieThe work is carried out in the laboratory of Balakrishnan Prithiviraj, an associate University. professor at Dalhousie University, and the projects main collaborator is Khalil In a 2018 scientific paper from the European Journal of Plant Pathology, BorzaAl-Mughrabi, a pathologist for the Potato Development Centre at New Brunswicks and his colleagues published data on the incidence and abundance of V. dahliaeDepartment of Agriculture, Aquaculture and Fisheries, and an adjunct professor at in soil from various agricultural fields in Prince Edward Island. To assess theDalhousie University.distribution of V. dahliae in this region, they carried out a survey of the incidenceIn New Brunswick, the incidence of disease is also very serious, says Borza. and abundance using real-time quantitative PCR. The researchers investigated 10Most soil samples and virtually every single potato stem tested before harvest fields from the major potato production areas for two successive years. Analysiswas infected with Verticillium, says Borza. This is a serious problem.of more than 200 soil samples revealed V. dahliae has a high incidence in theThe question, then, is how the infected potatoes are still alive. If its not province with an uneven distribution in the different locations analyzed.Verticillium alone that causes PED, it has to be something else, says Borza. In Over the two growing seasons, crop rotation provided limited control of theorder to better understand which other pathogens are involved in PED, Borza and pathogen, says Borza. his colleagues began using a molecular technique called amplicon-targeted next In 2019, in the same journal, Borza and his colleagues published a secondgeneration sequencing. This work began in 2018.paper, this one on the occurrence and abundance of V. dahliae and V. nonalfalfaeThe aim was to better understand problems related to PED, including the effect in agricultural fields in Nova Scotia. They were also assessed using real-timeof crop rotation on the diversity and abundance of the microbiota, including V. quantitative PCR.dahliae and P. penetrans, as well as the microbiota composition in the soil found in According to Borza, molecular data revealed V. dahliae has wider distributionthe proximity of healthy and diseased plants. They also wanted to understand the and a higher rate of incidence than V. nonalfalfae in the tested fields. V. dahliaeinfluence of soil fumigation on microbiome diversity. WINTER 2020 SPUDSMART.COM 39'