Sep 5, 2025Blue Diamond Growers report highlights pests, storms challenges
From Aug. 4 through Sept. 1, 2025, typical summer-time conditions gave way to monsoonal activity that added a splash of “color” to the start of the almond harvest, according to the latest Blue Diamond Growers Crop Progress Report. Daily highs during the period ranged from the mid-80s to as much as 106 degrees in the southern San Joaquin Valley, while morning lows hovered in the upper-50s to upper-60s.
According to the Sept. 3 crop progress report, the most significant weather event occurred Tuesday, Aug. 26, when monsoonal flows traveled northward along the east side of the Central Valley. The resulting thunderstorms dropped between 0.25 and 0.75 inches of rain from Kern through Stanislaus counties, with lighter amounts in parts of the Sacramento Valley.
Despite the storms, observers noted that “the pace of harvest increased dramatically during the period as harvest machinery moved aggressively through the early-maturing Nonpareil and Independence varieties.” However, operations were briefly halted in the rain-impacted east-side orchards, where water collected in low-lying areas inundating previously shaken almonds. Fortunately, the storms were a one-day event, and ensuing high heat and light breezes quickly promoted drying. Most growers resumed harvest in the final days of the period, while others worked to dry rain-soaked crops.
By the end of this harvest window, many huller and sheller managers reported that growers would finish shaking early-maturing varieties in the first week of September. In the most advanced west-side areas, operations had shifted to California type varieties, including Butte, Padre and, in the most advanced plantings, the late-harvesting Monterey.
While reject levels currently mirror those in the 2024 crop, pest pressure remains a concern. Damage from the navel orangeworm (NOW) continues, and feeding by leaf-footed plant bugs and stink bugs has increased. Notably, NOW trap captures surged sharply during hull split and again during the third flight in August — signaling heightened threat to later splitting varieties.
Invasive Carpophilus beetles have emerged in several orchards. Unlike other sap beetles common to California orchards, the Carpophilus beetle bores through almond shells to lay eggs, causing direct kernel damage. According to the report, “Pest Control Advisors and University of California researchers are monitoring orchards in an effort to understand the insect’s life cycle and develop best practices for control.”
Meanwhile, growers are reporting upticks in web-spinning mites, which may cause premature defoliation and undermine carbohydrate storage for the next crop cycle. In severe infestations, trees may leaf out or bloom before winter, depleting energy reserves and reducing yield potential. Some orchards considered at highest risk are being treated accordingly.
Most huller and sheller managers described “normal” machinery flows — a noticeable contrast to the “very fast pace experienced in the 2024 harvest.” Those unable to keep up with orchard output have diverted crops into stockpiles for later processing.
A special note highlights another brief interruption on Tuesday, Sept. 2, when early-morning thunderstorms passed over the Central Valley, this time spanning the entire width of the valley along Highway 99. Though heavier rain in some areas required a few days for drying, most orchards resumed operations later that day under hot afternoon temperatures nearing 100 degrees.
Despite weather disruptions and mounting pest pressures, California almond harvest is progressing steadily. Early-maturing orchards are wrapping up, while later varieties are beginning. Vigilant management of NOW, Carpophilus beetles, and mites will be essential to safeguard yield quality. The next crop progress report is scheduled for Monday, Sept. 29.
Photos courtesy of Anthony Scudder, Carla Youngblood, KC Clendenin, Austin Jackson, Nicole Jansen and Mel Machado.
