Jun 28, 2017

Ontario reports downy mildew on cucumber and cantaloupe

Downy mildew has been reported in Essex County in Ontario, Canada, putting the pathogen within easy striking distance of Michigan’s cucurbit crops. This pattern of downy mildew being detected in our immediate region around the time of July 4, 2017, has become well-established.

If fungicide sprays have not been applied to the most susceptible crops including cucumbers, cantaloupe and watermelon, this is an appropriate time to begin a fungicide program. For downy mildew symptoms on other cucurbit crops, see our tip sheet, “Monitoring and Managing Cucurbit Downy Mildew.”

Spore trapping for the pathogen has been ongoing in Michigan and downy mildew spores have not been found in significant numbers. This information is posted and updated each day and can be viewed at MSU’s Downy Mildew News.

Reports of downy mildew have increased across many counties in the southeastern U.S. in the last 10 days. States with the disease include Georgia, North Carolina, Alabama, Florida, South Carolina and Texas. In the northeastern U.S., downy mildew has been reported in Maryland. You can view confirmed outbreaks across the U.S. at the Cucurbit Downy Mildew Forecasting website.

– Mary Hausbeck, Michigan State University

Source: Michigan State University Extension