Downy mildew identified in Ontario
Cucurbit downy mildew has been confirmed in a small commercial slicing
cucumber field in the Aylmer, Ont. area.
June 23, 2008, Ridgetown, Ont. – Cucurbit downy mildew has been confirmed in a small commercial slicing cucumber field in the Aylmer, Ont. area.
Approximately 10 per cent of the plants show downy mildew symptoms, with only one to two infected leaves per plant. While this is slightly earlier than infection was first observed in 2007, the infection itself is much less severe than what was seen a year ago. Hopefully, with an aggressive management program, much of the innoculum can be destroyed, reducing the spread of the disease as much as possible.
All cucumber growers are recommended to apply a targeted downy mildew fungicide immediately. They should use either Ranman 400 SC or Tattoo C and continue to rotate between these two products every five to seven days, depending on the weather conditions. Frequent applications will be needed as the plants are growing rapidly and new growth must be protected.
When using Ranman 400SC, growers should apply a surfactant such as Sylgard 309. The Sylgard rate is 62 mL per ac (150 mL per ha). They should not use a surfactant with products such as Bravo, mancozeb or Tattoo C as these have the potential to burn the crop.
Anyone with questions or concerns is invited to contact Elaine Roddy at 519-674-1616 or at firstname.lastname@example.org.
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