Five plaintiffs have joined hundreds of others in suing Swiss agricultural company Syngenta AG, alleging Syngenta’s premature introduction of a new strain of corn into the Chinese market caused them to lose money.

The plaintiffs are farmers and farming organizations from eastern North Carolina who have come together to file a Syngenta GMO class action lawsuit, alleging that Syngenta so mishandled its introduction of its genetically modified corn strain known as Viptera into the Chinese market that it caused a drop in the price of U.S. corn, causing billions of dollars in losses across the U.S. corn industry.

Syngenta had developed Viptera, also known as MIR 162, to contain a protein that would kill common pests such as earworms and cutworms. In November 2013, before China had approved Viptera for import, Chinese officials found traces of Viptera in a shipment of U.S. corn. They responded not only by rejecting the shipment but also by banning all imports of U.S. corn from November 2013 until December 2014.

About the same time as the Chinese ban, the price of U.S. corn took a dive. The National Grain and Feed Association estimates the Chinese ban caused between $1 billion and $2.9 billion in losses.

The controversy has turned a huge segment of the corn industry against Syngenta. From individual farmers to large multinational corporations, plaintiffs are continuing to file new Syngenta corn class action lawsuits in courts all over the country, sometimes several dozen in a single day.

Cargill Inc. sued Syngenta in a Louisiana state court in September 2014, and the world’s largest corn processor Archer-Daniels Midland, or ADM, joined the fray in November 2014. ADM accused Syngenta of failing to use “reasonable stewardship practices” to prevent Viptera from ending up in the rest of the U.S. corn supply through cross-pollination.

In December 2014 the federal Judicial Panel on Multidistrict Litigation consolidated nine Syngenta corn class action lawsuits into a single multidistrict litigation, or MDL, and transferred them to the U.S. District Court for the District of Kansas. Since then, the number of lawsuits transferred into that MDL has grown to almost 1,500.

The class action lawsuits against Syngenta accuse the company of causing financial losses by downplaying the importance of the Chinese market – experts say China is the third largest importer of U.S. corn – and by misrepresenting Syngenta’s prospects for getting Chinese approval for Viptera. Some say that since Syngenta’s modified varieties of corn account for three percent of all acreage planted in the United States, it’s impossible to ensure shipments of U.S. corn do not contain at least some trace of Viptera.

Attorneys for the plaintiffs in the North Carolina class action lawsuit say Syngenta’s actions have significantly harmed the North Carolina economy. They believe Syngenta sold Viptera corn seeds to U.S. farmers knowing that China would not accept Viptera corn.

Syngenta says that the claims against the company has no merit. They contend they followed all regulatory requirements in both the United States and China.

Experts say the plaintiffs will have a tough time demonstrating just how much the drop in corn prices was attributable to the Chinese embargo. Some of the price drop could also be attributed to a surplus of corn in 2013 that occurred independent of the Chinese ban.