Adult carpophilus beetle, circled in blue, inside a hull split almond. (Photo: Jhalendra Rijal/ UC ANR)

Natalie Willis, Reporter, Valley Ag Voice

A new pest called the carpophilus beetle was recently found in the San Joaquin Valley, infesting almonds and pistachios in the confirmed counties of Stanislaus, Merced, Madera, and Kings. According to a press release from the University of California Agriculture and Natural Resources, the beetle is recognized as one of the top two pests of almond production in Australia. 

Damage caused by the carpophilus beetle occurs when adults and larvae feed on the kernel, causing reduced quality and yield. Despite the recent detection, the press release explained that the pest has likely been well-established in the valley, with some specimens from Merced County recognized from 2022 collections. 

Jhalendra Rijal, a UC integrated pest management advisor, is working alongside David Haviland, UCCE farm advisor in Kern County, to conduct a broader survey of orchards throughout the San Joaquin Valley to determine the outbreak’s extent. 

“It has likely been here for a few years based on the damage we’ve seen,” Rijal noted in the release.

Monitoring efforts are limited to direct inspection of hull split nuts for the presence of feeding holes, larvae, or adult beetles — a new pheromone lure is being developed in Australia to provide a more efficient monitoring tool.

The lifecycle of the carpophilus beetle is spent within the nut, restricting the opportunity to attack adults while they are exposed. The UC ANR team is expanding research activities on the beetle and started a plan of action for research and extension in 2024.

“We’re lucky to have colleagues abroad that have already been hammering away at this pest for almost a decade,” Haviland said in the release. “Hopefully, we can learn from their experiences and quickly get this new beetle under control.”

Haviland has also been involved in mitigation efforts and research of the Asian Citrus Psyllid, an invasive pest that poses a threat to California citrus.

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