The Pest Management Regulatory Agency (PMRA) has released its re-evaluation decision regarding chlorothalonil, a contact and protectant fungicide with a multi-site mode of action. This active ingredient controls a broad range of fungal diseases in field vegetable and orchard crops as well as greenhouse vegetables.

PMRA’s website says that continued registration of products containing chlorothalonil is acceptable. An evaluation of available scientific information found that most uses of chlorothalonil products meet current standards for protection of human health or the environment when used according to the conditions of registration, which include required amendments to label directions. Certain uses of chlorothalonil will be cancelled – for greenhouse cut flowers for example -- to address potential risks of concern for human health. Risk mitigation measures are required for all end-use products.

For human health, these measures include:

• All chlorothalonil products currently registered as dry flowable or water dispersible granules must be packaged in water soluble packaging

• Additional measures to mitigate exposure of mixers/loaders/applicators, including personal protection equipment and/or engineering controls

• Additional measures to mitigate exposure of postapplication workers, including reduced number of applications and restricted-entry intervals

• Additional label statements to clarify use directions

• Standard precautionary label statement to mitigate a potential drift into residential areas

For environmental health, these measures include: 

• Revised buffer zones

• Requirement for a vegetative filter strip

More details on the implications for growers will be published soon.