By: Elaine Roddy, OMAFRA and Cheryl Trueman, University of Guelph – Ridgetown Campus
There have been numerous new reports of cucurbit downy mildew in the Southern US last week. Late June to early-July is typically when downy mildew arrives in the Great Lakes region. The on-going wet weather, and speed at which the tropical storm fronts pass through the region mean that disease conditions can change very quickly.
At this time, use a broadspectrum fungicide such as cholorthalonil or mancozeb. Fungicides are most effective when used preventatively. Band spraying small plants helps to reduce the costs of the fungicide program. For information of band spraying, see Sprayers 101.com.
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.
2017 Downy Mildew Control Strategy for Cucumber Crops
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.