the summer. Nearly half the state’s strawberry acre- age is planted with proprietary varieties, the commission reported. Driscoll’s is the largest proprietary breeder, and its trade- marked “Berry Big” line are specifically cultivated to be larger for premium use in dipping and slicing, according to the com- pany. It licenses its cultivars to indepen- dent farms that grow, sell and market the fruit under the Driscoll’s brand. Berry Genetics and Plant Sciences Ge- netics also breed strawberry varieties for sale to farms in the Oxnard district, said Oleg Daugovish, UCCE adviser in Ven- tura County. The most popular varieties released by the university are Monterey, Alturas and Fronteras. Strawberry growers in 2016 lost their critical-use exemption to continue treating fields with methyl bromide. Ever since, the industry has funded research to identify effective controls for four soil-borne root diseases found up and down the coast. Funded research and trials continue for verticillium wilt, phytophthora crown rot, charcoal rot and strains of fusarium known as race 1 and 2, speakers told growers at an April 24 research production meeting in Santa Maria hosted by the strawberry commission. Gerald Holmes, director of the Straw- berry Center at Cal Poly, San Luis Obispo, Strawberries Continued from Page 6
effort to provide strawberry growers with disease-resistant plants. The work involves breeding and screening 2,000 new selec- tions each year for resistance to the four soil-borne diseases. UC varieties released before 2018 are susceptible to fusarium race 1, he noted. The university’s releases since 2023 all show 90% resistance to fusarium race 1, and new varieties are closer to being re- sistant to macrophomina, Feldmann said. “These plants often will look very healthy,” he said. “They may not have the same yield potential as a plant that is asymptomatic, but it’s a quite a lot better than it was.” Surfline, Monarch, Golden Gate, Key- stone and Eclipse—all UC varieties—have moderate resistance to verticillium and phytophthora, but they aren’t an improve- ment over earlier UC releases, including Monterey, Alturas and Portola. More than 50% of new varieties in the UC Davis program show few or no symp- toms of macrophomina, Feldmann said. Even a 25% mortality rate seen in a block of Portola summer strawberries in Guada- lupe represents progress, he added. “It isn’t perfect, but it’s a strong improve- ment over where we were a couple of short years ago,” Feldmann added. Rob McCarthy is a reporter in Ven- tura County. He can be reached at agalert@cfbf.com.
Warm winter temperatures accelerated the state’s strawberry production during the first quarter, with record-breaking volumes hitting the market this spring as California enters its peak season.
showed the results of a three-year survey to detect which soil-borne pathogens were present in the state’s growing districts. His team collected samples of dead and dying plants at 100 sites starting in Watsonville in 2021 and found all four pathogens present in 20% to 30% of all strawberry fields. The team in 2022 collected samples in Oxnard, where charcoal rot from the fun- gal pathogen macrophomina phaseolina was detected in two-thirds of the sample sites. Santa Maria in 2023 tested positive
for all four soil-borne diseases, with mac- rophomina present in half the sites, the data showed. “This gives us benchmark. In any giv- en year, this might look a little different,” Holmes said, adding the survey data showed how the soil-borne pathogens in strawberries differ in the northern growing region compared to the southern region. Mitchell Feldmann, director of the Strawberry Breeding and Research Group at UC Davis, is leading the university’s
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May 6, 2026 Ag Alert 7
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