Downy mildew of brassicas (Hyaloperonospora parasitica syn. Peronospora parasitica) is a fungal-like oomycete that can be devastating in cooler, wet weather. While the ideal temperature for downy mildew development is 8-16˚C it can infect in temperatures outside that range. Prolonged leaf wetness due to fog, dew, or evening irrigation can create ideal conditions for the pathogen to develop.
Downy mildew is most devastating on Continue reading Downy mildew of brassica vegetables
This information is updated from an earlier article by Janice LeBoeuf.
We have had multiple reports of late blight in conventionally managed tomato fields this week. Typically, this disease is well managed in tomatoes with a broadspectrum fungicide program including chlorothalonil. However, high disease pressure due to environmental conditions, combined with a dense leaf canopy and rapid growth may have resulted in poor spray coverage and reduced efficacy.
Commercial growers should scout often and ensure they are using fungicides with good late blight activity in their fungicide program. When late blight is in the area, spray intervals should be shortened.
Under continued high disease pressure, growers should consider adding a targeted late blight fungicide to the spray program. If late blight has been identified in a field, use a fungicide with curative and antisporulent activity, see the table below for late blight fungicides and their properties. Continue reading Late blight alert – July 27th, 2017
Cheryl Trueman, University of Guelph – Ridgetown Campus
Risk of downy mildew to cucumbers and cantaloupe remains high, with new reports regularly occurring throughout the great lakes region.
Scouting for downy mildew in pickling cucumber fields in Norfolk County began on June 13 and in Kent County on June 19. This is the final cucumber downy mildew scouting report for the 2017 season.
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
Cucurbit Downy Mildew Report for the Week of July 4th, 2017
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.
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.
Late blight has been confirmed on tomatoes in Chatham-Kent.
Recent weather has been conducive to the development and spread of late blight. Commercial growers should scout often and ensure they are using fungicides with good late blight activity in their fungicide program. When late blight is in the area, spray intervals should be shortened. Continue reading Late blight alert – June 28
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.
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.
Onion thrips (Thrips tabaci) feed on more than just onions; they also feed on cabbage, leaf lettuce, a variety of other vegetables and fruits, field crops, and many weed species. Thrips are unique from other insects as they have rasping-sucking mouthparts that allow them to scratch the cell walls of leaves, suck up the cell contents including the chlorophyll, and leave behind a shiny, translucent trail on the leaf. A single female can produce Continue reading Scouting for onion thrips
