By: Cheryl Trueman, Ridgetown Campus – University of Guelph
About these tables:
These tables were created using results from replicated processing tomato field trials at the Ridgetown Campus, University of Guelph. Please contact the author for more information on research methods and copies of full reports. The tables are for information only and do not guarantee successful results with the use of any product.
Always check the most recent version of the product label before applying any product.
Only products labelled for ‘control’ of the specific disease are included in each table except where noted.
Cheryl Trueman, Ridgetown Campus, University of Guelph
Rachel Riddle, Simcoe Research Station, Dept. of Plant Agriculture, University of Guelph
Elaine Roddy, OMAFRA
This article is an updated version of ‘2016 University of Guelph Cucumber Downy Mildew Results’ by Elaine Roddy, which first appeared May 1, 2017.
Comparison of fungicide programs In 2016 and 2017, Cheryl Trueman compared several different cucumber downy mildew control programs in plots at the University of Guelph Ridgetown Campus.
Different product rotations included:
Bravo-only applied 6 times.
a high input strategy that focused on optimal control and resistance management: Orondis Ultra A+B; Torrent; Zampro; Orondis Ultra A+B; Torrent; Zampro.
a low-input strategy that focused on early control and resistance management, switching to lower-cost fungicides in the final weeks of harvest: Orondis Ultra A + B (plus Bravo); Torrent; Zampro; Bravo; Bravo; Bravo.
a single application of Orondis Ultra, applied early followed by the other targeted downy mildew fungicides (Orondis Ultra A + B; Torrent ; Zampro; Torrent; Zampro; Torrent).
The 67th Annual Muck Vegetable Growers Conference will be held March 28-29 at the Bradford and District Memorial Community located at 125 Simcoe St., Bradford, ON. The conference is free and registration starts at 8:30. No pre-registration is required. For more details please see: http://www.uoguelph.ca/muckcrop/muckconference.html
The Pest Management Regulatory Agency (PMRA) recently announced the approval of a minor use label expansion registration for Reason® 500SC Fungicide for control of downy mildew on basil and an amendment to update the label to include management of downy mildew on the new Brassica vegetable crop groups 5-13 and 4-13B in Canada. The head and stem Brassica vegetable group includes cabbage, napa cabbage, Brussels sprouts, cauliflower and broccoli and the new Brassica leafy greens crop group includes arugula, Chinese broccoli, Chinese cabbage, bok choy, collards, cress, kale, mizuna, mustard greens, etc. Reason® Fungicide was already labeled for use on a number of crops in Canada for control of several diseases. Continue reading Reason® 500SC Fungicide label expanded for management of downy mildew on basil and Brassica crops→
Jason Deveau, Application Technology Specialist – OMAFRA;
Dennis Van Dyk, Vegetable Crop Specialist – OMAFRA
In recent years, Syngenta has been promoting the Defy 3D nozzle in the UK, which is a 100° flat fan, designed to run alternating 38° forward or backward along the boom. They prescribe a boom height of 50 to 75 cm, 30-40 psi, and travel speeds of 10 to 14 km/h in cereals and vegetables. Compared to a conventional flat fan, they claim that the angle and medium-coarse droplets promise less drift and improved coverage.
In 2017, Hypro and John Deere began distributing the Defy 3D in North America. Our goal was to explore coverage from the 3D in vegetable crops. We compared the nozzle’s performance to common grower practices in onion, potato and carrot in the Holland Marsh area of Ontario.
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.
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→
This is a re-post from 2016 – Late-July to early-August is the key time for powdery mildew management! With any disease, preventative management provides the best control.
Powdery mildew typically arrives in Southern Ontario in mid-to-late July. Plants are most susceptible to infection during the fruit sizing and development. Poor control results in decreased yield and poor fruit quality at harvest. The threshold for treatment is 1 lesions/50 plants. Optimum powdery mildew control is a combination of variety selection, fungicide timing and fungicide selection.
Powdery Mildew Lesion on the Lower Leaf Surface
Cheryl Trueman, a vegetable pest management researcher at the University of Guelph’s Ridgetown Campus, has been conducting powdery mildew efficacy trials since 2009. In these trials, several products consistently provided good control of powdery mildew. These products are powdery mildew targeted, and have a single site mode of action. To prevent the development of resistance, it is essential to always rotate between different fungicide groups and/or tank mix with a broad spectrum fungicide.
Powdery Mildew Targeted Fungicides Showing Consistent Control in the Ridgetown Field Trials:
Group 13: Quintec (quinoxyfen)
Quintec was the most consistent powdery mildew product tested in Ridgetown. It provided excellent control in 4/5 years and good control in 1/5 years tested.
Group U8: Vivando (metrafenone)
Vivando provided excellent control in 1/3 years and good control in 2/3 years and tested.
Group 7: Fontelis (penthiopyrad), Aprovia (benzovindiflupyr), Sercadis (fluapyroxad) and Pristine (boscalid/pyraclostrobin).
Fontellis was somewhat less consistent. Control with this produce ranged from excellent to poor, depending on the year. It provided excellent control in 1/5 years, good control in 2/5 years and poor control in 2/5 years. Note: Aprovia, Sercadis and Pristine were not tested in the Ridgetown Campus trials.
Group 3: Inspire (difenoconazole), Proline (prothioconazole) and Quadris Top (azoxystrobin/difenoconazole)
Inspire provided a level of control similar to Fontelis; good control in 3/5 years, and poor control in 2/5 years. Proline and Quadris Top were only tested for one year in the Ridgetown trials, in which they both provided good control.
Fungicides containing chlorothalonil(Bravo ZN and Echo) provided a lower level of powdery mildew control, but are still better than the untreated checks. They also control a broad range of other foliar diseases including scab and alternaria.
Research in Ontario and other jurisdictions indicates that the group 11 (QoI) fungicides, Cabrio (pyraclostrobin) and azoxystrobin (a component of Quadris Top) no longer control powdery mildew. However, they may provide control of other cucurbit diseases such as anthracnose and alternaria.
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.
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.
Information for commercial vegetable production in Ontario
