PMRA Announces Chlorothalonil Final Decision

by Tom Hsiang
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.  

Editor's note:  the 87 page document is under review by WCTA staff.  If you have questions, please email