On June 21, the Pest Management Regulatory Agency (PMRA) announced that the fungicide mancozeb will no longer be allowed in horticultural crops except for foliar use in potatoes.  A maximum of 10 applications per year will be allowed on potatoes with seven-day application intervals. That’s a relief for potato growers protecting their crops from late blight, but little solace for many growers of tomatoes right through to tender fruit.

 “This is a perplexing ruling,” says Craig Hunter, crop protection advisor, Ontario Fruit and Vegetable Growers’ Association.  “If the product is safe for potatoes and poses no risks to human health or the environment as the PMRA says, then it should be a level playing field for all horticultural crops.” 

The issue, as Hunter sees it, is that both the United States and the European Union have re-evaluated and approved the use of mancozeb.

“The logic for banning most uses of mancozeb in Canada is not clear or supported by scientific evidence,” says Hunter. “It is especially puzzling when more than 400,000 acres of potatoes can get up to 10 applications (>4M acres) and all the onion seed needed for Canada cannot be treated with less than 10 kg total!”

Here is the excerpt from the PMRA decision for mancozeb.  

The PMRA has completed the re-evaluation of mancozeb. Under the authority of the Pest Control Products Act, the PMRA has found the continued registration of products containing mancozeb acceptable for foliar application to potatoes. An evaluation of available scientific information found that foliar application of mancozeb to potatoes meets current standards for protection of human health and the environment, when used according to the conditions of registration which include required amendments to label directions. All other uses of mancozeb are being cancelled due to unacceptable risks to human health and will be removed from the labels. Label amendments, as summarized below and listed in Appendix III of RVD2018-21, are required for all end-use products

Human Health

To protect the general population, the following risk-reduction measures are required for continued registration of mancozeb in Canada:

• ​Cancel all Canadian uses of mancozeb with the exception of foliar application on potatoes.

• Permit a maximum of 10 applications per year on potatoes at a maximum application rate of 1.69 kg a.i./ha with 7-day application intervals and a 1-day pre-harvest interval using aerial or ground spray only.