Why Proposed Dicamba Restrictions Could Impact Canadian Soybean Seed Production

The future of dicamba in Canada is increasingly tied to more than just weed control. A recent special review decision in September 2025 has signaled potential restrictions on key dicamba uses in double-tier (DT) soybeans, which could significantly impact Canadian soybean seed production. Manitoba Agriculture officials have highlighted that the outcome of this review could affect weed management strategies across the Prairies and beyond.

In a presentation at the CropConnect Conference in Winnipeg, Manitoba Regulations and Minor Use Specialist Pratisara Bajracharya and Seeds Specialist Kim Brown explained the complex regulatory landscape surrounding pesticide decisions in Canada. They detailed the intricate process that could shape the future of dicamba use in the country, emphasizing the interplay between federal, provincial, and environmental regulations.

Bajracharya began by outlining the three main entities involved in pesticide regulation in Canada. At the federal level, pesticide registration, re-evaluation, and special reviews are overseen by Health Canada’s Pest Management Regulatory Agency (PMRA), which operates under the Pest Control Products Act. This agency is responsible for ensuring the safety and efficacy of pesticides registered for use in Canada.

On the provincial level, Manitoba regulates pesticides through the Pesticides and Fertilizers Control Act. This legislation governs the licensing of pesticide applicators and dealers, ensuring that those involved in applying or distributing pesticides are qualified and capable of doing so safely.

A third layer of regulation is provided by the Environment Act, which can require licensing for large pesticide storage sites and permits for applications in areas where the public may have access. This act aims to protect the environment and public health by managing the risks associated with pesticide use.

The dicamba debate has been a topic of concern for farmers for years, but the current situation is particularly unique. Bajracharya explained that the current process is a “special review,” not just a routine re-evaluation. Routine re-evaluations occur on a long cycle, approximately every 15 years, during which the PMRA revisits older registrations using updated scientific standards. However, special reviews can be initiated at any time under Section 17 of the Pest Control Products Act. These reviews are typically triggered when there is new information or concerns about the safety of a pesticide, necessitating a more thorough examination of its risks and benefits.

In the case of dicamba, the special review has been prompted by growing concerns about its potential to harm non-target plants, such as soybean crops. Dicamba is a broad-spectrum herbicide commonly used to control weeds in soybean fields. However, its mode of action—inhibiting the enzyme PEP carboxykinase (PEPC)—can also affect soybean plants, particularly when applied at higher rates or under certain conditions.

The proposed restrictions on dicamba use in DT soybeans could have significant implications for Canadian soybean seed production. DT soybeans are a high-yielding variety that is resistant to glyphosate, a common herbicide. Farmers often rely on dicamba as a complementary herbicide to manage weeds that are resistant to glyphosate. If dicamba use is restricted in DT soybeans, farmers may need to explore alternative weed management strategies, potentially leading to changes in seed production practices.

Manitoba Agriculture officials have acknowledged that the outcome of the dicamba special review could impact weed management strategies across the Prairies. Farmers and applicators will need to demonstrate their ability to use dicamba without causing damage to non-target plants, such as soybean crops. This may involve adopting more precise application techniques, using lower rates of the herbicide, or employing alternative herbicides.

The future of dicamba in Canada is thus intertwined with the country’s regulatory system and the ability of farmers and applicators to adapt their practices. The special review process is a critical opportunity to assess the risks and benefits of dicamba use in soybean production, ensuring that the herbicide is used in a manner that protects both agricultural productivity and the environment.

As the dicamba debate continues, Canadian farmers and agricultural officials must navigate the complex regulatory landscape to ensure the sustainable use of this important herbicide. The outcome of the special review will undoubtedly shape the future of soybean production in Canada, highlighting the need for adaptable weed management strategies and a robust regulatory framework that balances agricultural needs with environmental concerns.