By Jamie Martin
California’s processing tomato industry has introduced new voluntary sanitation guidelines to manage branched broomrape, a parasitic weed that threatens crop productivity. The weed attaches to plant roots and removes vital nutrients, reducing yield and farm income.
Broomrape seeds are extremely small and long‑lasting, making control difficult. Since its re‑emergence in 2017, the weed has raised serious concerns across tomato‑growing regions.
To address this issue, the University of California, Davis is leading research efforts in partnership with industry groups, government agencies, and growers. Scientists are developing equipment cleaning systems, testing weed control tools, and studying ways to detect and limit the spread of weeds.
“There’s 1,000 acres that are actually reported but we know from observation that it’s probably much greater than that,” said Cassandra Swett, a UC Davis plant pathologist who is leading efforts to sanitize field equipment.
“There are two main goals: reduce the economic impacts of broomrape on growers in the affected region by allowing them to harvest, and on the other side, keep broomrape out of the regions that do not currently have it,” said Swett.
Previously, fields with broomrape were required to be destroyed before harvest. New compliance guidelines now allow harvesting if growers follow approved management and equipment cleaning standards developed by the California Broomrape Board.
In 2025, most growers and processors agreed to comply with these measures, and mandatory adoption is expected for the 2026 season. Tomato canneries have also committed to setting up wash stations and sanitation systems for transport equipment.
“With the risk of crop quarantine off the table for growers under the compliance agreements, we can talk about the problem out in the open,” said Brad Hanson, a professor of Cooperative Extension in plant sciences and an ad hoc member of the Broomrape Control Board. “The daylighting part of this has been really helpful because for the last five years, we’ve been really in the dark.”
Although cleaning harvesters can take several hours, new automated technologies are being tested to improve efficiency. Faster and effective sanitation help reduce production delays and operational costs.
The updated rules have encouraged better reporting and cooperation, helping the industry gain a clearer understanding of the issue. Early action and shared responsibility are improving protection for tomato crops and reducing the risk to other farm sectors.
Photo Credit: gettyimages-bastetamn
Categories: National