Vol. 16, No. 16. July 2, 2009

The Ohio State University Extension Vegetable Crops

On the WEB at: http://vegnet.osu.edu

In This Issue

1. Downy Mildew Confirmed in Sandusky County, Ohio

Downy Mildew Confirmed in Sandusky County, Ohio
Sally Miller, OSU Department of Plant Pathology

Downy mildew has been confirmed in a large commercial pickling cucumber field in Sandusky County.  The incidence of the disease was about 1% in this field.

If not already started, cucumber growers in northern Ohio counties should begin treatment of cucumber fields with the more effective fungicides against downy mildew such as Presidio, Ranman and Previcur Flex.  These products must be used in a program with other effective fungicides and must be alternated to reduce the possibility of fungicide insensitivity developing in the downy mildew pathogen population.  Please see the Ohio Vegetable Control Guide (OSU Extension Bulletin 672) and previous Vegnet issues for details.  It is also recommended that growers consult the cucurbit downy mildew forecasting website (http://www.ces.ncsu.edu/depts/pp/cucurbit/) for information on weather patterns and predicted risk of downt mildew development.  We are not recommending an intensive fungicide program for other vine crops at this time but these crops should be protected with a broad spectrum protectant fungicide such as Bravo or Manzate.