President Trump has continued his threats to close the border to Mexico, which could have a disastrous effect on United States agriculture. National Corn Growers Association Vice President Kevin Ross says Mexico is the top customer for U.S. corn, so closing off trade would be a train wreck.

The Iowa farmer says the move would also label the U.S. as an unreliable supplier and comes at a time when the nation’s farmers are already working to rebuild that market. The re-negotiation of NAFTA had forced many Mexican customers to buy from other sources like Brazil.

Ross says Mexico is also a top export market for pork and beef and that also has a trickle-down effect on corn farmers.

If the President actually goes through with the threat it has the potential to unravel the USMCA and they can’t afford to have that happen.