The carpophilus beetle, a serious pest threatening California’s almond industry, is officially documented in only four counties — Stanislaus, Merced, Madera, and Kings. However, according to entomologists and industry experts, its presence is far more widespread, raising concerns about the limitations of official reporting and its impact on securing resources for control and mitigation.
Houston Wilson, a Cooperative Extension specialist in the Department of Entomology at UC Riverside, has been surveying reports and conducting research on the beetle in collaboration with other UC and USDA researchers. “We’ve identified infested orchards — both almonds and pistachios — from every county within the San Joaquin Valley,” Wilson said. “We’re also hearing reports of crop damage from the Sacramento Valley (Sacramento through Butte County), but we have yet to directly confirm it there due to limited survey efforts.”
The Importance of Official Documentation
Despite mounting evidence of the carpophilus beetle’s spread, official state records remain limited. Wilson explains that for a find to be considered “official,” the county Agricultural Commissioner must collect a sample and submit it to the California Department of Food and Agriculture (CDFA) for verification. The current process means that many beetle infestations, though identified by researchers, remain unofficial.
“While we have unofficial records from our survey efforts, my understanding is that the official records only reflect what has gone through the CDFA process,” Wilson said.
For growers, the discrepancy between unofficial and official findings is more than just a technicality — it could also affect the allocation of resources. According to the Almond Alliance, securing state and federal assistance depends on having documented proof of the beetle’s widespread presence.
“The widespread documentation of the carpophilus beetle serves as a vital indicator of the extent and severity of the issue,” said Almond Alliance CEO Alexi Rodriguez. “When more counties report official beetle findings, it underscores the pervasive nature of the problem, highlighting its impact beyond isolated areas.”
Challenges in Reporting
Wilson acknowledges that the reporting process can be complicated, but he and his team actively assist growers. “If a grower contacts me about suspected beetle damage, I usually visit the farm to assess the situation,” he said. “If we confirm the presence of the carpophilus beetle in a county that hasn’t had an official report, we advise them to contact their Agricultural Commissioner and guide them through the reporting process.”
Rodriguez recognizes the difficulties growers face in reporting. “I want to acknowledge that the reporting process is not easy; however, expanding the network of official findings will allow us to advocate for more effective solutions by highlighting the problem’s regional and national significance,” she said.
Identifying the Carpophilus Beetle
For growers looking to detect the beetle, Wilson advises examining nuts in windrows, where nuts can be easily sampled. “The most apparent sign is a fine, powdery white frass on the nut, which results from beetle larvae tunneling into the kernel,” he said. “If you blow that frass away, you might see a circular hole in the shell where the adult beetle chewed through to lay its eggs. Inside, the larvae create distinctive oval-shaped tunnels in the kernel itself.”
Wilson is part of a team that last year developed a pest identification guide to help growers differentiate carpophilus beetle damage from other pests, such as navel orangeworm or ants.
Securing Support for Growers
To address the growing concern, the Almond Alliance continues to work with officials at both the state and federal levels. “This engagement is expected to lead to more coordinated and robust interventions, mobilizing the necessary support and funding to mitigate the impact of beetle infestations on ecosystems, agriculture, and local economies,” Rodriguez said.
Meanwhile, research efforts continue. “We’ve secured funding from the Almond Board of California and the California Pistachio Research Board for a second year, and we’ve now leveraged that into a larger pool of funding from the USDA,” Wilson said.
Growers can also take advantage of upcoming pest identification workshops organized by the Almond Board of California in March, where they can learn more about identifying carpophilus beetle damage.
A Call to Action
With the evidence pointing to a much wider distribution of the carpophilus beetle than official records reflect, the push for more growers to report infestations is crucial. “If we don’t have official documentation, we can’t make the case for more resources,” Rodriguez emphasized. “We urge growers to work with their local Agricultural Commissioners to ensure the beetle’s spread is formally recognized.”
By increasing official reports, the almond industry can strengthen its efforts to combat the carpophilus beetle, securing the necessary funding and support to protect California’s valuable almond crops. — By the Almond Board of California
