Mexican ranchers and other users of imported corn are trying to get their government to back off from a ban on genetically modified corn, saying it would upend if not ruin their businesses.

A Dec. 31 decree from the Mexican government banned domestic farmers from growing GMO corn, and set a three-year phaseout for imports of GMO corn. The measure was depicted as a way to protect Mexico’s corn farmers from the flood of cheap imported corn that has undercut them since the implementation of the North American Free Trade Agreement in 1994.

But Mexican ranchers and other users of imported corn point out that they are dependent on imports. While Mexico grows about 25 million tons of white corn, used in tortillas and other foods, every year, it imports about 18 million tons for cattle feed, starch and other uses, most of it from the U.S. and nearly all of it GMO.

“This decree is completely divorced from reality,” the head of a Mexican corn-users trade group told Reuters.

The same Mexican governmental decree also bans glyphosate, an herbicide widely used in Mexico. The trade group chief pointed out that this will depress crop yields, making the country more dependent than ever on imported corn.