Three Kansas farmers have filed suit against Syngenta Corp., a Swiss maker of a genetically modified strain of corn.

They join a growing number of interests across the country that have gone to court over the corn.

In the three separate lawsuits, filed last week in Federal District Court in Wichita, Oran Winter of Sedgwick County, Wayne Schmidt of Reno County and Eugene Goering of McPherson County accuse Syngenta of disrupting the export market to China for American corn farmers.

According to the suit, Syngenta released its genetically modified corn with the Agrisure Viptera trait in 2009. Agrisure Viptera is aimed at preventing yield and quality damage caused by black cutworm, corn earworm, western bean cutworm and similar insects.

U..S. officials approved the use of the corn in 2010, and subsequently, most countries that buy corn from U.S. producers also approved the variety.

The suit contends that Syngenta misleadingly assured farmers it was close to getting Chinese approval. But in late 2013, afraid that corn with the Agrisure Viptera trait – which was still not approved by China – was mixed with other U.S. corn, China reduced all U.S. corn imports.