Cucurbit Downy Mildew Report for the Week of July 4th, 2017

Elaine Roddy, OMAFRA and Cheryl Trueman, University of Guelph – Ridgetown Campus

Cucurbit downy mildew was confirmed on June 28th.  Additional reports now include the areas of Norfolk, Oxford and Kent. The risk of downy mildew infections remains high throughout Southern Ontario.

At this time all cucumber growers should use only targeted downy mildew fungicides.

Cantaloupe/muskmelon growers should alternate between broadspectrum fungicides and downy mildew fungicides.  In melon crops, broadspectrum fungicides are required to manage other foliar diseases including alternaria, anthracnose and powdery mildew.

Scouting for downy mildew in pickling cucumber fields in Norfolk County began on June 13 and in Kent County on June 19.

You can track sightings of downy mildew in North America on the IPMpipe Cucurbit Downy Mildew website.

More information:
2017 Downy Mildew Control Strategy for Cucumber Crops

2016 Fungicide efficacy and fungicide program results

The downy mildew scouting program is sponsored by the Ontario Cucumber Research Committee. Field scouting in Norfolk County is managed by Tania Keirsebilck-Martin at the Norfolk Fruit Growers’
Association. Field scouting in Kent County is managed by Cheryl  Trueman at the Ridgetown Campus, University of Guelph. We thank Elaine Roddy, OMAFRA vegetable specialist, for her guidance with
implementing this program.