UC Davis, Pistachio Research Board seek grower input on climate impacts to fruit set
UC Davis and the California Pistachio Research Board are asking growers to report bloom and fruit set conditions following unusual weather.
California pistachio growers are being asked to participate in a University of California, Davis (UCD) and California Pistachio Research Board (CPRB) survey designed to help researchers better understand how recent weather patterns affected bloom, fertilization and fruit set.
California’s pistachio industry covers more than 600,000 acres and generates more than $2.5 billion annually. While the 2025-2026 winter appeared to provide typical cold and foggy conditions, researchers said some orchards may not have accumulated enough winter chill. A March heatwave during bloom also coincided with reports of irregular bloom and nut set across portions of the state’s production region.
Researchers said impacts varied widely among orchards. Some experienced significant production issues while others reported little or no effect under similar growing conditions, suggesting additional factors may be influencing tree performance.
The survey will help researchers evaluate how climate variability affected orchards during this critical stage of development. Data collected may also support several CPRB-funded research projects focused on improving pistachio yield and quality.
Growers are encouraged to complete the survey for each orchard with distinct performance, even when management practices such as irrigation and fertilization were similar. Responses are anonymous unless participants choose to provide contact information.
Researchers said broader participation will provide a more complete picture to guide future research priorities and management strategies for California pistachio production.