United States Trade Representative Katherine Tai announced the request on June 2 in response to “Mexican measures concerning products of agricultural biotechnology.”

Dispute settlement rules are in Chapter 31 of the USMCA.

The Mexican government published a decree in February that called for a ban on GMO corn in tortillas or dough and instructed the government to phase out GMO corn gradually produced for human consumption and animal feed. These phase-out measures would begin in 2024.

According to the U.S., this move is “inconsistent with several of (Mexico’s) obligations in the Sanitary and Phytosanitary Measures and Market Access chapters of the USMCA.”

Mexico is the second-largest market for U.S. corn, importing nearly $5 billion of it in 2022. This includes about 17 million metric tons of GMO yellow corn for animal feed. Of course, Canada also exports corn to Mexico.