Cucurbit Downy Mildew Forecast


The Cucurbit Downy Mildew (CDM) forecasts have changed rapidly with the storms coming up from the south. The risk is increasing, particularly for southern New England. See https://cdm.ipmpipe.org/forecasting/ to see up-to-the-minute forecasts.

NH cucurbit producers should be using protectant fungicides if they are planning to do so. As a reminder, we would not reocmmend using materials specific for downy mildew until the disease has been confirmed in the region. After the upcoming period of rainy weather, growers should be scouting fields carefully for any symptoms, and be ready to switch to targeted fungicides when CDM is found in the state. See below for some photos of symptoms on pumpkin/winter squash.

For a complete list of labeled materials, please consult the New England Management Guide. 

Please continue to monitor cucurbit crops. If you suspect you have CDM infections, please take photos and submit them to your local field or state specialist. Confirmation of infections helps us know where the disease is present so that we can warn others, and also helps improve the accuracy of the predictive model!

The underside of a leaf with cucurbit downy mildew lesions;
sporulation is visible.
The top side of a cucurbit leaf with cucurbit downy mildew; 
note vein-delimited yellow spots.

 

Author(s)

Rebecca Sideman
Sustainable Horticulture State Specialist
Full Extension State Spec/Prof
Phone: (603) 862-3203
Office: Cooperative Extension, Kendall Hall, Durham, NH 03824