Cucurbit downy mildew has been reported on pickling cucumbers and cantaloupe in Essex County. This is the first field report for this disease in 2017.
All Ontario cucumber growers should now switch from a broadspectrum program to a 3-product rotation using targeted downy mildew fungicides.
The following products have shown the most consistent results in fungicides trials at the University of Guelph, Ridgetown and Simcoe campuses. Under high downy mildew pressure, follow a spray interval that is no longer than 7-days.
- Orondis Ultra A (mandipropamid) + Orondis Ultra B (oxathiapiprolin) + Bravo (chlorothalonil)
- Torrent (cyazofamid)
- Zampro (ametoctradin/dimethomorph)
For more information about the most effective spray rotations, see: 2016 University of Guelph Cucumber Downy Mildew Results.
July 5th, 2016: cucurbit downy mildew was identified today in a processing cucumber field in Kent County, Ontario. Now that the disease is present in the great lakes region, growers should immediately move to a targeted downy mildew spray program.
See the 2016 Downy Mildew Control Strategy for Cucumber Crops for an up-to-date list of registered control products.
Use only the downy mildew targeted products listed in the strategy. Research trials in Ridgetown, Simcoe and in the neighbouring states have shown these products to be the most consistent from year-to-year.
Rotate between all three of the targeted downy mildew products, starting with the most effective product, Orondis Ultra, and then rotate to either Zampro or Torrent within 7-days.
If you have any questions about the cucumber downy mildew control strategy, please call 519 674 1616 or email firstname.lastname@example.org
Cucurbit Downy Mildew has been identified in a cucumber field in Chatham-Kent, Ontario. Levels were very low (< 1% of the field). The infection likely occurred within the past few days. However, this does indicate that all area cucumber and melon fields are at a high risk of developing downy mildew at this time.
Continue to use a preventative fungicide program, rotating between the targeted downy mildew fungicides. For more information on fungicide selection, see the Downy Mildew Report – July 11, 2014.
Over the past few years there have been a number of new fungicide registrations for cucurbit crops in Canada. Each one has its own particular strengths; however it is important to find the right fit within the fungicide program.
Depending on the disease, the actual infection rates greatly between the different cucurbit crops. For example, cucumbers are highly susceptible to downy mildew while pumpkins typically have a much greater level of tolerance to this disease. The more significant diseases for each cucurbit type are listed below (Table 1. Significant Cucurbit Diseases by Crop). When planning a preventative fungicide program, it is useful to keep these diseases in mind. Continue reading New Cucurbit Fungicides for 2014