Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
Downy mildew was found on July 7 in the sentinel plot near Georgetown on cucumber. Only a few leaves were exhibiting symptoms and less than 5% of the leaf surface was infected. The fungus was not prospering but it was present. This fungus can survive the heat of the last few days and with fog in the early morning the fungus appears to be persisting. Growers should be including downy mildew specific products in their fungicide programs at this time. The risk of spread from southern sources is low at the present time. New reports of downy mildew have been posted from MI, WI, and additional counties in OH and NY. Continue to monitor for downy mildew and check the ipmPIPE website for the latest forecast at http://cdm.ipmpipe.org/.