Duarte Nursery Sued to Get Back About $800,000 in State-Mandated Fees for Grapevine Research. A Court Called Its Appeal “Long on Innuendo and Short on Evidence.”

In the late 1980s, phylloxera, a tiny insect that feeds on grapevine roots, destroyed more than 50,000 acres of vineyards in Napa and Sonoma counties. In 1992, the Legislature created the California Grape Rootstock Improvement Commission to fund research on healthier rootstock. Every commercial grape rootstock nursery pays into it through mandatory assessments.

Duarte Nursery paid the assessments but challenged them in court twice. In the 1990s, it argued in federal court that the fee violated its rights to free speech and association. The Ninth Circuit Court of Appeals rejected that claim in 1998.

The nursery then sued in state court, arguing that the assessments violated its liberty interests and due process rights, and sought refunds of about $800,000 paid since 2000. The trial court ruled against it, and in August 2015 the Third District Court of Appeal affirmed. “In an appeal long on innuendo and short on evidence,” the court wrote, “plaintiff insinuates that a self-interested university researcher and some of plaintiff’s competitors used propaganda to dupe the Legislature.” The opinion also notes that the nursery admitted using a small amount of a rootstock developed through the commission’s research. The California Supreme Court declined to review the case.

Alexandra Duarte, a Republican, is running for California State Senate District 4 on the Nov. 3, 2026 ballot. She is married to former Rep. John Duarte, who has served as the nursery’s president.