FRESNO, Calif. — When Jose Dolores began picking grapes at Gerawan Farming in California’s San Joaquin Valley in 1990, the company was paying a little over the state minimum wage of $4.25 an hour. “We just weren’t making enough, and everything cost a lot. That’s why people wanted the union,” he recalls.

Dolores was one of over 1,000 workers at Gerawan that year, when its workers voted for the United Farm Workers union to represent them. But they didn’t get any further. Mike Gerawan, one of the company’s owners, repeatedly challenged the validity of the union vote. The one time he met with the UFW he said, “I don’t want the union, and I don’t need the union.”

That effectively ended bargaining on a contract, which union reps believe would have provided better working conditions and more protection for the laborers. Another owner, Dan Gerawan, declined to comment, but a statement sent by the company publicist, Erin Shaw, blamed the union for the stalled efforts: “The UFW abandoned Gerawan employees without ever negotiating a collective bargaining agreement.” Over the years, with no contract, Gerawan Farms grew to become one of the nation’s largest growers, with more than 5,000 workers.

It was only in 2012, after a new state law on mandatory mediation was implemented, that the UFW was able to go back to Gerawan to demand a renewal of the talks. While the company did meet with the union, it also attempted to have the UFW removed as the representative of the workers. Even more importantly, it is challenging the constitutionality of the law in state court.

Losing this fight could have devastating consequences for the UFW and, indirectly, for farmworker unions in other states, since it would make it much more difficult for workers to get growers to agree on a contract. No real union can survive indefinitely without being able to win contracts and thus being able to gain members and make substantial changes in wages and conditions. Federal law has never covered farmworkers, and outside of California, no state has a law giving farmworkers a legal process for recognition and bargaining. Those few union agreements that exist outside the state have been the product of yearslong campaigns and boycotts. As a result, only a tiny percentage of the nation’s farmworkers have union contracts, and wages and conditions in farm labor are worse than in almost any other occupation. California, however, has been able to use state legislation to address grower intransigence. If it works, the example may spread, which is why other growers are watching this case closely.