PMRA Issues Re-evaluation Decision for Chlorothalonil

May 15th, 2018

Prepared by Tom Hsiang, Ph.D., University of Guelph

The commonly used fungicide, chlorothalonil, found in a large variety of turf fungicides including Daconil, has been undergoing review by the Canadian Government. The Health Canada Pest Management Regulatory Agency just recently issued a final re-evaluation decision chlorothalonil (RVD2018-11, Chlorothalonil and Its Associated End-use Products for Agricultural and Turf Uses). A summary can be found at

Contrary to initial reports, there are turf uses remaining on the label:

For turf snow molds, a single application per year will be permitted, containing up to 12 kg a.i./ha or 120 grams per 100 square meters (or about 4 ounces per thousand square feet of active ingredient).

For turf diseases during other seasons, there will be up to two permitted applications at a minimum 14 day interval, with up to 9.5 kg a.i./ha or 95 grams per 100 square meters per application on golf courses.

For sod farms, there are also two permitted applications, but at 7 day intervals with up to 4.8 kg a.i./ha or 48 grams per 100 square meters.

Re-entry into treated sites can occur when the sprays have dried.

Companies have 24 months to change their labels on products containing chlorothalonil to reflect these requirements.


Additional items of note for reference (added by CGSA staff following review):

Note that additional information is found by reviewing the entire report, other items of note will be added to the end-use product labels and will include:

  • Applications should be done with consideration of wind speed, wind direction, temperature inversions, application equipment and sprayer settings due to potential drift to non-target areas of human habitation and areas of human activity.
  • For products with ornamental uses - not for use on greenhouse ornamental cut flowers nor roses grown for cut flowers.
  • For products with golf course uses - Do not allow the public to enter into treated golf courses following late fall application for snow mould.