Cucurbit Downy Mildew Alert for Pumpkins and Winter Squash
Cucurbit downy mildew (CDM) was confirmed Sunday, August 18 on pumpkin in New Jersey. Pumpkin and winter squash growers should now regularly apply both broad-spectrum and downy mildew-targeted fungicides to their crops. Recommended broad-spectrum materials are chlorothalonil or copper, both of which are effective against both CDM and cucurbit powdery mildew. Recommended CDM-targeted materials include Elumin, Zing!, Gavel, Orondis Opti, Zampro, Omega, Previcur Flex, and Ranman. Rotate between 2 targeted materials for resistance management.
Presidio, Revus, and Forum are NOT recommended, due to pathogen resistance.
The DM strain attacking cucumbers and cantaloupes reached Maine with the storm on August 9. All Cucurbit crops should be on a spray schedule to protect from Downy Mildew.
For more information on CDM management, see Managing Cucurbit Downy and Powdery Mildew.
For pictures of CDM on different cucurbit crops, visit Cornell’s photo gallery of Cucurbit Downey Mildew.
Mark Hutton, Ph.D.
(He/Him/His)
Vegetable Specialist
University of Maine Cooperative Extension
Assoc. Professor Vegetable Crops
Highmoor Farm, P.O. Box 179
Monmouth, ME 04259-0179
207-933-2100 ext 104