Washington Opens a New Trade Front with Preliminary Duties on Canadian Mushrooms

The United States has opened a new front in its escalating trade dispute with Canada after the U.S. Department of Commerce proposed preliminary anti-dumping duties on imports of fresh Canadian mushrooms.

Under the preliminary determination announced on Tuesday, July 14, 2026, most Canadian fresh mushroom exports could face a duty rate of 8.26 per cent.

U.S. trade authorities said their initial investigation found that some Canadian mushrooms were being sold in the American market at prices below what they considered fair value.

The finding is not a final ruling, and Canadian exporters have not been definitively found to have violated U.S. trade rules. The investigation must still pass through additional administrative and legal stages before permanent duties can be imposed.

Separate preliminary rates were assigned to three Canadian companies. Champ’s Fresh Farms faces a proposed rate of 8.71 per cent, while Highline Produce was assigned the highest rate at 11.80 per cent. Farmers’ Fresh Mushrooms received a preliminary rate of two per cent.

Most other Canadian producers and exporters would be subject to the general rate of 8.26 per cent.

The latest measure follows a separate U.S. decision in May to impose preliminary countervailing duties on Canadian mushrooms over allegations that producers benefited from government subsidies.

Those rates ranged from 1.62 per cent for Champ’s Fresh Farms to 4.97 per cent for Farmers’ Fresh Mushrooms, while most other exporters were assigned a rate of 2.84 per cent.

Canadian mushrooms could therefore face two different categories of trade penalties: countervailing duties linked to alleged government subsidies and anti-dumping duties related to the prices charged in the U.S. market.

The combined financial burden could make Canadian products less competitive and force importers, distributors and retailers to reconsider prices and supply arrangements.

Mushrooms Canada, which represents producers across the country, rejected the suggestion that Canadian companies were engaging in unfair trade.

The organization argued that the preliminary rates reflect the complexity of U.S. anti-dumping calculations rather than the commercial reality of the highly integrated Canadian and American mushroom markets.

It also said a direct comparison of average selling prices in both countries would not show that Canadian mushrooms were being dumped into the United States at unfairly low prices.

The dispute is significant because the United States is a major destination for Canadian mushroom exports.

U.S. trade figures show that imports of fresh Canadian mushrooms were valued at approximately US$349.8 million in 2024, representing nearly 69.85 million kilograms of produce. That was up from roughly US$315.4 million in 2022.

The investigation began in January 2026 following a complaint from a coalition of U.S. mushroom producers. The group alleged that Canadian companies were exporting mushrooms below fair market value while benefiting from government support that harmed American competitors.

The Department of Commerce is expected to issue its final decisions in the anti-dumping and countervailing duty cases by late September 2026, unless the timetable is extended.

The U.S. International Trade Commission must then determine whether Canadian imports have caused material injury, or threaten to cause injury, to the American mushroom industry.

If the commission finds no evidence of material harm, the investigation could be terminated and the duties removed. If it supports the Commerce Department’s conclusions, the preliminary rates could become long-term tariffs.

The case adds another agricultural product to the growing list of trade disputes between Ottawa and Washington, raising fresh concerns among Canadian farmers and exporters about access to their largest international market.