2025: Canola Disease Survey in North Dakota

In 2025, canola was grown in 48 counties of North Dakota. Of these, 21 major canola-producing counties were surveyed following swathing or direct harvest, with 94 fields scouted. During this process, the project team monitored the incidence of five diseases: Verticillium stripe, white mold, blackleg, clubroot, and powdery mildew. In addition to the disease monitoring, purple stem, a stress response exhibited by canola plants to biotic or abiotic factors, was also assessed.

Results:

Table 1: Percentage of canola fields exhibiting disease during the annual assessment across canola-growing counties in North Dakota.

In summary, major canola diseases were observed in a large number of fields in North Dakota; however, the incidence levels were low. When elaborated, Verticillium stripe appeared in 92% of surveyed canola fields, with an average disease incidence rate of 12% in each field visited. White mold was found in 83% of fields (6% incidence), blackleg in 66% (5% incidence), powdery mildew in 9% (4% incidence), and purple stem in 10% (3% incidence) of fields surveyed. Clubroot was present only in Cavalier County, detected in 35% of the fields surveyed (with an average incidence of 41%) (Tables 1 & 2).

Table 2: Incidence percentages of canola diseases observed in each field visited during the annual survey conducted in North Dakota.