Cucurbit Downy Mildew Update – July 31, 2009

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Downy mildew continues to occur in commercial pickling cucumber fields. It is now widespread in all three counties in home gardens as well as on both slicing and pickling cucumber varieties. So far it has only been found on cucumbers. Conditions continue to be favorable for downy mildew on all our cucurbits. Be sure to be including downy mildew fungicides such as Ranman, Previcur Flex, Tanos and Presidio for downy mildew control. They all need to be tank mixed with a protectant fungicide. Disease pressure is increasing and waiting until the three leaf stage may not provide the control desired if infected plantings are nearby. Check the website often for the latest forecast at http://cdm.ipmpipe.org.