Mancozeb Changes A’Coming

By now, you are likely aware of the Pest Management Regulatory Agency (PMRA) re-evaluation decision for mancozeb fungicides including Manzate Pro-Stick, Manzate Max, Penncozeb 75 Raincoat and Dithane Rainshield. For the full report, see RVD2020-12, Mancozeb and Its Associated End-use Products.

The new risk-reduction measures come into effect November 19, 2022 and include:

New rate
4.5 kg a.i. / ha
Minimum interval between applications
7 days
Maximum applications per year
4
Restricted entry interval
12 hours – general re-entry 35 days – hand thinning
Preharvest interval
77 days

The labels for these products are now updated on the PMRA label search to reflect the new use restrictions. While PMRA encourages growers to follow updated labels immediately, the previously approved labels are valid until November 2022. Growers will be responsible for acquiring the previously approved label for documentation. This can be provided by emailing PMRA at hc.pmra.info-arla.sc@canada.ca. In your email, be sure to include the product name and registration number of the label you are requesting.

As indicated in the above table, after November 2022 the maximum allowable applications will be limited to 4 per year. Unfortunately for apple growers, this application limit applies to both full and half rates of mancozeb. 

So, what now? As a starting point, the April 2021 Orchard Network Newsletter article, Considerations for the Future of Apple Scab Management looks at how and when to use the tools left to manage scab and summer disease.

Kristy Grigg-McGuffin
Kristy Grigg-McGuffin

Horticulture IPM Specialist, OMAFRA