American farmers already stung by President Donald Trump's trade wars now face billions of dollars in potential losses as controversial data from the U.S. government snuffs out a rally in corn.

The Agriculture Department on Monday said farmers planted a bigger corn area than analysts estimated and pegged crop yields that also exceeded expectations, sparking the biggest rout in futures since 2013. That was a blow to growers who were holding back supplies, hoping a rally that started in May due to delayed sowing would extend through the fall.

The decline represents a potential loss of almost $3.5 billion for U.S. farmers, according to the American Farm Bureau, and is another setback for them after prices fell following the USDA's previous acreage report, which was widely criticized for containing outdated data.