Basil downy mildew has now been detected in potted basil across Ontario and many areas of North America. Spores will likely be released by basil plants from garden centres and home gardens. Field growers should be monitoring fields closely for symptoms of the disease. Apply fungicides preventatively when conditions are conducive to disease development. Conditions that promote basil downy mildew include warm temperatures, high humidity and periods of leaf wetness, which can include dew periods. The weather over the past week has been favourable for disease development. Although field infection has never been detected this early in the season in Ontario, there is limited experience with this disease and the right conditions may lead to spread from home gardens into the field. For a description of symptoms and for registered fungicides, please refer to the previous downy mildew post (Click here).