Courtesy of Dr Bhabesh Dutta UGA Extension Vegetable Pathologist:
Downy mildew of squash has been detected from Thomas County in Georgia (May 3, 2016). These observations indicate that inoculum of downy mildew is currently in GA and under favorable conditions (cool and wet conditions) potential disease outbreak in cucurbit can occur. I would suggest our cucurbit growers to look for the downy mildew symptoms in their fields and start applying protective spray of below stated fungicides.
Watermelon: Rotation (foliar application) with Orondis+Bravo/Manzate;
Don’t use Bravo after fruit set.
Other cucurbits: Ranman+Bravo; Previcur flex+Bravo
If Orondis was used as a soil application, please do not use it as foliar (use restriction according to label).
If Orondis was not used as a soil application, foliar application can be done for controlling downy mildew.