Downy mildew identified in Kent County
June 29, 2009 By Elaine Roddy OMAFRA
June 29, 2009, Dresden, Ont. – The first field infection of downy
mildew in Ontario was identified in a cucumber field near Dresden on
June 26, 2009.
June 29, 2009, Dresden, Ont. – The first field infection of downy mildew in Ontario was identified in a cucumber field near Dresden on June 26, 2009.
Approximately 20 per cent of the field is infected with two per cent of the leaf area affected. The infection is patchy in the field; the area closest to the windbreak is more severely impacted.
All growers should be on a regular preventative fungicide program. Do not wait to spray. Control of this disease is much more effective when fungicides are used prior to infection.
Rotate between Tattoo C and Ranman 400SC. Apply Tattoo C at a rate of 1.2-2.7 L/ha (0.72-1.1 L/acre). The rate for Ranman is 150-200 mL/ha (40-80 mL/acre) add 150 mL/ha (62 mL/ac) of Sylgard 309 as a surfactant. Tattoo C does not need a surfactant. Use the higher rates under heavy disease pressure or when the canopy begins to close over.
The preharvest intervals are one day for Ranman and two days for Tattoo C. Tattoo also has a two day re-entry interval.
Always rotate between fungicides from different chemical families. Use a minimum spray volume of 30 to 60 gallons per acre. Apply a preventative fungicide before a rainfall event or prior to overhead irrigation.
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