Incidence and abundance of Verticillium dahliae in soil from various agricultural fields in Prince Edward Island, Canada

Verticillium dahliae causes wilt in potatoes and it is associated with the potato early dying syndrome. Previous studies showed that V. dahliae is present in Prince Edward Island, a major potato producing province in Canada; however, its current incidence and abundance are largely unknown. In recent years an increase in the frequency of V. dahliae-related diseases was observed in the province, affecting tuber yields. To assess the distribution of V. dahliae in this region, a survey of the incidence and abundance of this pathogen was carried out using real -time quantitative PCR. Ten fields, from the major potato production areas, cultivated with potato or with rotating crops, were investigated for two successive years. Analysis by qPCR of DNA extracted from over 200 soil samples revealed that V. dahliae has a high incidence in the province with an uneven distribution in the different locations analyzed and over the two growing seasons, while crop rotation provided a limited control of the pathogen.