Colorado and nine other states joined the Federal Trade Commission’s lawsuit against pesticide makers Syngenta and Corteva on Thursday, accusing them of engaging in anti-competitive practices. 

The lawsuit filed in U.S. District Court alleges that the companies use loyalty programs with pesticide distributors to exclude generic competitors from the market. The lawsuit claims the companies influence distributors to sell their products after their patents expire by giving distributors “incentive payments” for keeping their purchases of generic products below a certain threshold.

The lawsuit argues that these practices are unlawful and have inflated prices for farmers and consumers, potentially costing farmers millions of dollars each year.

“Effective enforcement of the antitrust laws to protect farmers and to address concerns of inflated food prices is a priority,” said Colorado Attorney General Phil Weiser. “Ensuring that dominant firms, including ones who previously benefited from patent protection, cannot maintain their market share through anticompetitive means is critical to protecting fair competition.”

Companies such as Syngenta and Corteva can initially develop and patent active ingredients in their pesticides, granting them the exclusive right to sell the products for several years. Typically, after those protections expire, generic manufacturers enter the market with products with the same active ingredients, leading to increased competition and dramatic price reductions for farmers and consumers.

Syngenta and Corteva are among the largest makers of crop-protection products in the United States. According to the lawsuit, the companies have entered into loyalty program agreements with substantially all leading distributors in the country, cutting out rival generic products from distribution.

In a statement, Syngenta described the incentive payments as a “voluntary and industry-standard program” that pesticide companies have utilized for decades.

“Syngenta strongly disagrees with the FTC’s complaint, which it believes is contrary to the facts and the law and is without merit,” the statement said. “This program is only one of several incentive programs offered by Syngenta in the U.S., and we are disappointed that the FTC has failed to appreciate the beneficial effects that these rebate programs provide to our channel partners and to growers.” 

The lawsuit argues that Syngenta and Corteva’s practices violate state and federal laws, including the Federal Trade Commission Act and the Clayton Act. Colorado and the other plaintiffs are asking the court to end Syngenta and Corteva’s loyalty programs and grant monetary relief and attorney fees, among other remedies. 

In addition to Colorado and the Federal Trade Commission, the lawsuit was filed by the attorneys general of California, Illinois, Indiana, Iowa, Minnesota, Nebraska, Oregon, Texas and Wisconsin.