Although almond harvest may be wrapping up, the work needed to prepare orchards for next season has already begun. Post-harvest priorities include monitoring for disease, irrigating trees, pruning and managing pests.
Brent Holtz with the University of California Cooperative Extension advises growers to watch for red leaf blotch and rust. Bright orange spots on leaves may indicate red leaf blotch, while orange and black spores can be signs of rust. This year’s warm March appears to have increased the severity of rust, making it important to avoid irrigation practices that keep orchards humid for extended periods.
However, growers should not stop irrigating altogether. Water should be applied as soon as the harvested nuts are removed from the orchard floor. Dr. David Goldhamer, emeritus irrigation specialist with UC Davis, says almond trees can use up to 11 acre-inches of water after harvest if their leaves remain active. Proper post-harvest irrigation can also help move salt below the trees’ root zone.
Growers can also begin pruning mature orchards immediately after harvest instead of waiting until dormancy. Pruning early gives wounds time to heal before rainfall, reducing the risk of fungal diseases. While studies indicate pruning does not significantly improve almond yields, it remains necessary to provide enough space for orchard equipment to pass between trees.
Fall is also a good time to manage gophers, ground squirrels and mice. Baiting or fumigation can help control ground squirrels before they enter hibernation. Growers should also look for pieces of almond shells left in tree crotches, which may indicate mouse activity.
For more information about post-harvest almond orchard management, read the full article in the September issue of Pacific Nut Producer Magazine.
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The 2025 California Almond Objective Measurement Report published Thursday by the U.S. Department of Agriculture’s National Agricultural Statistics Service (USDA-NASS) estimates that the crop harvested in 2025 will come in at 3.0 billion meat pounds.
The Objective Estimate is up 7 percent from USDA-NASS’s Subjective Forecast in May and 10 percent higher than last year’s crop of 2.73 billion meat pounds.
“The Objective Measurement reflects the hard work by California almond growers during uncertain times,” said Clarice Turner, president and CEO of the Almond Board of California. “While shipping has remained consistently strong, we know uncertainty remains surrounding future trade policies. We continue to engage with trade partners and stakeholders to encourage constructive solutions that support fair and stable trade so California almonds can continue to be enjoyed by consumers around the world.”
The 2024 harvest yielded 2.73 billion pounds, 2.5% below the 2024 Objective Report estimate, reflecting the difficulty of precisely forecasting crop size given the current fluctuations in weather and economic factors.
The report shared the 2025 almond crop experienced variable weather during bloom, which began in early February and peaked in the middle of the month. Storms brought rain, wind and hail, which hindered bee hours and blossom growth. Conditions improved in early March with warm temperatures accelerating the crop’s progress through the end of bloom. Mild temperatures and timely rain in spring supported nut growth and continued through early summer, lessening heat stress in orchards. Lower than normal pest and disease pressure have been reported. Harvest is expected to begin on time.
“While this year’s Objective Measurement estimate is higher than the industry expected, shipments remain strong. We are focused on innovation—expanding almond applications, reaching consumers through new channels, and opening markets around the world,” added Turner. “The Almond Board is actively driving initiatives to stimulate demand around the world.”
USDA-NASS’ forecasted yield is 2,160 pounds per acre, up from 1,980 in 2024. The forecast for the average nut set per tree is 4,364, an increase of 7 percent compared to 2024. The Nonpareil average nut set of 4,526 is 9 percent higher than last year. The average kernel weight for all varieties sampled was 1.60 grams, down 0.6 percent from the 2024 average weight. The Nonpareil average kernel weight was 1.60 grams, down 2 percent from the 2024 average weight.
The 2025 Objective Report is based on actual almond counts using a statistically rigorous methodology. The survey was conducted from May 24 to June 28 and 1,892 trees were sampled in 946 orchards. USDA-NASS conducts the annual Objective Report, Subjective Forecast and Nursery Survey to provide the California almond industry with the data needed to make informed business decisions.
Leaffooted bug is a sporadic pest in almond, but damage can be significant in years when pest pressure is high. The pest may evade early detection by growers and PCAs because it overwinters as adults in vegetation outside of the orchard and tends to colonize the upper tree canopy, rendering it generally out of sight. As a result, pest pressure is often realized after damage has occurred. The damage may vary considerably between almond varieties, adding yet another challenge for diagnosis.
In Tulare County, heavy leaffooted bug damage was observed in May 2025 in almond orchards surrounded by citrus.Adult leaffooted bugs (Figure 1A) overwintered in the citrus and then entered the neighboring almond orchards in March and April. By early May, symptoms of infestation included extensive nut drop (Figure 2A) and gummosis on the nuts (Figure 2B). Although the adults were not observed in the orchard, the pest was identified based on the observation of the characteristic egg strands of leaffooted bug (Figure 1B). In orchards with Nonpariel and Aldrich, both varieties were affected; however, the nut drop was more extensive in Aldrich than Nonpareil (Figure 2A).
The full impact of the pest may not be realized until harvest because the quality of affected nuts remaining on the tree may also be compromised, thus reducing crop value. Nuts that are stung in late April to early July can be severely shriveled, have sunken lesions, or a brown spot depending on how developed the kernel was prior to feeding (Fig. 3, row 2-5).These nuts stay in the tree, are harvested, and can significantly increase the percentage of nuts classified as inedible during nut quality assessments.When examining a library sample of damaged kernels at harvest, nuts damaged by leaffooted bug fall into the same category as stink bug damage, as kernels damaged by these two pests are indistinguishable.
In 2007, UCCE Kern County Farm Advisors David Haviland and Mario Viveros had the opportunity to evaluate the relative susceptibility of 15 almond varieties to leaffooted bug damage. That year, leaffooted bug invaded a Kern County variety trial research block that included 15 varieties planted in replicated, randomized blocks. This unique situation allowed for unbiased evaluation of the performance of varieties under equivalent pest pressure. Results indicated that the average number of aborted nuts per tree ranged from 0 to 33% of the total crop. Additionally, at harvest, the estimated rejects from leaffooted bug damage ranged from 0 to 30% of the harvested yield. Researchers also noted that crop loss varied by variety, with Fritz exhibiting the highest crop loss at 63%, followed by Sonora, Aldrich, Livingston, Monterey and Carmel.The other varieties in the block had 3% or less total damage from the pest.
The underlying basis for the differential susceptibility of almond varieties to leaffooted bug is unknown. Damage does not appear to be related to harvest date or shell hardness at harvest. Other factors such as plant volatiles, hull thickness, or shell hardness in April and May when the bugs are present may play a role in varietal susceptibility. Haviland and Viveros also noted that varietal susceptibility is somewhat relative, explaining that Wood Colony exhibited low susceptibility to leaffooted bug in the research plot, but significant damage was reported on Wood Colony in commercial orchards when combined with less susceptible varieties (ie. Nonpariel and Carmel).These observations indicate that leaffooted bug prefers certain varieties, but in the absence of a preferred variety, the pest will remain in the orchard and feed on the most preferable variety of the less-preferred varieties present in the orchard.
The 2025 observations in Tulare County, taken in consideration with the 2007 data from the UCCE variety trial suggest that the best way to monitor leaffooted bug is to focus attention on the most susceptible variety in the field. Gummosis and nut drop in the most susceptible variety will serve as an indicator of pest pressure in a given orchard. Growers with Fritz, Sonora, Aldrich, and Livingston should be extra vigilant in monitoring pest pressure.Haviland and Viveros note that orchards composed of relatively unsusceptible varieties will have characteristically lower risk of leaffooted bug damage. Additionally, growers and PCAs should consider pest pressure from surrounding orchards and landscape plants that may serve as overwintering sites for the adults, thus contributing to the cryptic nature of the pest.
Management programs for leaffooted bug consist of monitoring for the pest and spraying primarily with pyrethroids, when needed. Pest management guidelines for leaffooted bug and other pests can be found at www.ipm.ucanr.edu and reports of Almond Board of California-sponsored research can be found at https://www.almonds.com/research-database. — By Elizabeth Fichtner, UCCE Farm Advisor, Tulare County, and David Haviland, UCCE Entomology Advisor, Kern County
Figure 2. Aborted nuts were prevalent on Aldrich, but the neighboring Nonpareil exhibited minimal damage (A). Gummosis and egg strands on aborted nuts indicated leaffooted bug damage (B).
Figure 3. Leaffooted bug predation affects the quality of nuts remaining on the tree. Unaffected nuts are represented in row 1; affected nuts of varying quality are represented in rows 2-5.
Figure 1. Leaffooted bug adults (A) are difficult to scout. Pest pressure is evident by the gummosis at feeding sites and the deposition of eggs in strands (B). Alternate hosts may harbor overwintering populations of leaffooted bug (C and D). Photos A, C, and D: W. Bentley.Figure 2. Aborted nuts were prevalent on Aldrich, but the neighboring Nonpareil exhibited minimal damage (A). Gummosis and egg strands on aborted nuts indicated leaffooted bug damage (B).Figure 3. Leaffooted bug predation affects the quality of nuts remaining on the tree. Unaffected nuts are represented in row 1; affected nuts of varying quality are represented in rows 2-5.
