Germany’s competition regulator has fined seven pesticide wholesalers a total of €155 million (U.S. $173 million) for operating a cartel for 17 years between 1998 and 2015.

Several individuals, reported to be managers, have also been fined.

The companies fined for their role in the cartel—which includes the four largest players in the German wholesale pesticides market—are Agravis Raiffeisen; Agro Agrargrosshandel; BayWa; BSL Betriebsmittel Service Logistik; Getreide; Raiffeisen Waren; and ZG Raiffeisen.

The seven companies—as well as the individuals involved—acknowledged their roles in colluding on price-fixing at an early stage and cooperated with authorities, leading to a reduction in fines.

Another company involved in the scheme—Beiselen—qualified for leniency for being the first to cooperate after investigators carried out dawn raids in March 2015 and so escaped a penalty.

The Bundeskartellamt, the German competition authority, says investigations against two other companies are ongoing, while the agency has stopped proceedings against a further three companies and two associations.

Beginning in 1998, the regulator says, the cartel worked together to create biannual price lists for its members’ plant protection products and stopped only after the Bundeskartellamt raided their premises in 2015.

At first the companies met several times a year to agree to the joint price lists, according to the watchdog, though in later years they generally arranged them either in writing or over the phone.

“Especially during the first few years, some companies simply used the agreed price list to set their own prices and basically just added their respective company logo to the final list,” said Bundeskartellamt President Andreas Mundt in a statement.

Despite agreeing to settle, both the companies and individuals concerned can appeal the fines at the Düsseldorf Higher Regional Court.