The early potato harvest in Southwestern Ontario is yielding exceptional results, according to Dr. Eugenia Banks, a renowned potato specialist with the Ontario Potato Board.
In her latest newsletter, Dr. Banks reported that the quality of the early potatoes is excellent, with yields surpassing expectations in numerous fields. Despite the dry weather, strategic irrigation in some areas has helped maintain these favorable conditions.
Dr. Banks mentioned that late blight has been found in a few fields in Ontario, and it was detected in Michigan this week. While there is no epidemic as severe as last year’s, the disease has been effectively controlled with two applications of Orondis Ultra, alternated with other late blight (LB) fungicides.
To assist growers in managing late blight, Dr. Banks included updated guidelines for the use of foliar applications of late blight-specific fungicides. These guidelines now incorporate the level of activity of fungicides according to the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and growers’ experiences. The efficacy ratings range from zero stars, indicating resistance or ineffectiveness, to four stars, signifying high-level control.
Below is a summary of the late blight-specific fungicides and their efficacy:
- Orondis Ultra: 4 stars (High Level Control)
- Revus: 3 stars (Control)
- Curzate DF 60%: 3 stars (Control)
- Ranman: 3 stars (Control)
- Gavel MZ: 3 stars (Control)
- Allegro: 3 stars (Control)
- Presidio: 1 star (Suppression, no control)
- Phosphites: 4 stars (High Level Control for tuber blight control in storage)
- Forum: 2 stars (Suppression only, requires tank mixing with another LB-specific fungicide)
- Zampro: 3 stars (Control)
Dr. Banks extended her gratitude to Mark Van Oostrum for his significant contributions to developing these guidelines.
Additionally, Dr. Banks advised growers to remain vigilant during the flowering stage of the potato plants, which demands substantial energy and can lead to the appearance of Botrytis, white mold, and brown leaf spot. She recommended scouting fields and applying broad-spectrum fungicides registered for controlling these diseases, along with early blight.
In closing, Dr. Banks reminded readers of the upcoming Potato Field Day at HJV Equipment on August 22, expressing her hope to see many of them there.
Contact:
Dr. Eugenia Banks, Potato Specialist, Ontario Potato Board
EugeniaBanks@onpotato.ca
Image: Potato variety trial in Ontario. Credit Dr. Eugenia Banks
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