Do date there have been no confirmed reports of downy mildew in the Great Lakes region. However, activity does continue in the Southern US. The ipmPIPE website tracks the epidemic (figure 1) and also forecasts the potential spread of the disease.
Historically, downy mildew has arrived in this area in late-June to early July. We have found that using an early broad spectrum preventative fungicide program, staring at vine development, will result in better season long control of the disease. This is especially important if weather conditions turn wet and overcast, with storm originating in the Southern US.
For complete details see the 2016 Downy Mildew Control Strategy for Cucumber Crops.
If you suspect downy mildew in your cucurbit crop, please notify OMAFRA, your agri-business supplier or your grading station. Downy mildew is a community disease and open communication is vital to ensuring a healthy crop.