Cucurbit downy mildew has been identified in a cucumber field in Kent County. Disease presence is very low with less than one percent of the plants exhibiting lesions at this time. The field has been treated with preventative fungicides. This is the first report of cucurbit downy mildew in Ontario for the 2023 growing season. Given the wet weather over the weekend, we can assume that fields across Ontario are at high risk of developing symptoms over the coming days.
Scout all cucumber and cantaloupe fields for signs and symptoms. Look for distinct angular lesions (dark green, to yellow, to tan coloured) on the upper leaf surface and grey fungal spores on the corresponding lower leaf surface.
For information on control, refer to the article, Downy Mildew – get out and scout!
The 2023 Cucumber Downy Mildew Scouting Program is funded through the Ontario Processing Vegetable Growers and delivered by Tomecek Agronomy Services in Kent County and the Norfolk Fruit Growers Association in Norfolk/Elgin.