Updates for California Nut Crops

December 2025 

Just a few months ago California nut crop orchards were alive with activity. Now, temperatures are falling, daylight hours are shorter, and trees are settling into winter shutdown. Almonds and pistachios go dormant in December, which means they are physiologically focused on nutrient and carbohydrate storage rather than leaf or nut development. Growers can use this brief reprieve to knock out important orchard management tasks.

Almond Updates 

California almond orchards are settling into dormancy, which means trees are building up nutrient reserves for the next growing season. This resting phase is the perfect time to focus on orchard floor maintenance by planting winter cover crops. Cover crops may help improve soil health and water infiltration, as well as provide habitat for pollinators ahead of bloom. December is also the month to start winter sanitation. Removal of mummy nuts leaves few resources for overwintering navel orangeworm, which means lower populations in orchards come spring time. Growers should aim to have all of their mummies removed (via shaking or poling) by February 1st of next year. 

Pistachio Updates

Pistachios are also experiencing a period of rest in December. Trees are using this downtime to rebuild carbohydrate reserves after a high-yield "on" production year. Growers are currently focused on monitoring chill hour accumulation, which gives operations a good indication of when to expect budbreak and what bloom patterns might look like in the spring. Chill hour accumulation begins on November 1st, and aims to count the number of hours with orchard temps between ~32°F-47°F. It is important that trees experience an adequate amount of chill in order for male and female bloom to occur in sync. If not, poor pollination may occur, leading to lower nut set and increased blanks.

Key Production Considerations

• Winter Sanitation: Begin the process of removing mummy nuts from orchards. Identify areas of historically high pressure or those with large numbers of mummies to prioritize.
  
• Cover Crops: Consider planting a winter cover crop to improve soil health and increase pollinator habitats in the spring. 

From the Field 

Photo: Kayla Manning, Customer Experience Manager at Suterra 

• Did you stop by our booth at the Blue Diamond Growers Annual meeting in November? Ignacio Valdez and Ralph Gutierrez had the opportunity to discuss their area of expertise: field service. Suterra is proud to offer local expertise to California growers across the state. 

Live Educational Events 

Photo: Emily Symmes, PhD., shares the advantages in drone applications of sprayable NOW pheromones at Chico State's Center for Regenerative Agriculture.

Interested in pheromone education or have a question for our team? Connect with us at an upcoming industry event:

• December 4th: NW Hort Expo in Wenatchee, WA
• December 10-12th: Almond Conference in Sacramento, CA

NOW Mating Disruption Solutions

Puffer NOW Ace

• Delivers a precise dose of pheromone for season-long control of navel orangeworm in nut crops.
• Rebates and early order programs are available to reduce input costs for growers. 
  • Contact our customer experience team at customercare@suterra.com for more information or visit www.suterra.com/rebate. 

CheckMate NOW-F

• Spring applications targeting the first flight give your NOW spray program a crucial head-start by preventing population buildup and improving efficacy of later treatments.
• New for 2026: Suterra is offering a grower rebate for operations that apply three sprays to the same acreage. Total investment after rebate for a three-spray seasonal program is just $79 per planted acre. 

November 2025

As California’s nut crop harvest comes to a close, trees begin transitioning into their dormant phase. November brings cooler temperatures and shorter daylight hours, signaling trees to shift energy from photosynthesis to nutrient storage for winter. Dormancy allows trees to replenish nutrients for the next season, and for growers to complete post-harvest management tasks.

Almond Updates

Almond orchards across California are moving into dormancy. There are several production practices that growers can complete to support early shoot growth and bloom in 2026. Orchard tissue and soil sampling may identify nutrient imbalances among blocks, guiding fertilizer or soil amendment applications. Fall applications of boron, zinc, and potassium have demonstrated a variety of positive orchard results. Growers may also randomly sample spurs throughout the orchard to determine if scale and mite treatment is necessary. If you haven’t evaluated your 2025 harvest samples, now is a great time to do so, as the results may inform pest management strategies for next year.

Pistachio Updates

Pistachios and almonds are experiencing similar physiological milestones in November. All pistachio orchards in California have completed their harvest, and trees are starting to wind down into dormancy. Pistachios are alternate bearing trees, and because 2025 was an “on” year, tree carbohydrates and nutrients were depleted and need time to regenerate. Pistachio trees also require a certain amount of chill hours to ensure strong development and uniform bloom in spring. Growers may track chill hours from November to February to get a better idea of what to expect at bloom. Although orchard management varies from grower to grower, some UC farm advisors suggest holding off on nutrient applications until spring to avoid loss during winter leaching that may occur.

Key Production Considerations 

• Postharvest Sanitation: Continue surveying orchards for mummy nuts and implement winter sanitation programs. Identify areas of historically high pressure or those with large numbers of mummies to prioritize.
• Tree Recovery: After harvest, replenish almond orchards with nutrient applications to support bud development and ensure tree health heading into dormancy.
• Cover Crops: Consider planting cover crops to improve soil health and increase pollinator habitats in the spring. 
• Pruning: Avoid pruning damaged branches from trees before rainfall events, as this can lead to the rapid spread of disease.

From the Field 

Photo: Jeanie Morton, Marketing Project Manager at Suterra 

• Did you meet the Suterra team at this year’s CAPCA Annual Conference? In addition to fielding PCA and grower questions at our booth, we had the opportunity to present a few times on the main stage. Emily Symmes, Ph.D., highlighted the future of chemical drone applications, sharing in-field examples and results. Haydn Lenz, PCA, presented a label update on our new organic formulation of vine mealybug pheromone. As always, we are proud to partner with industry professionals to advance effective, sustainable pest management.

Live Educational Events 

Photo: Emily Symmes, PhD., shares the advantages in drone applications of sprayable NOW pheromones at Chico State's Center for Regenerative Agriculture.

Interested in education about pheromone delivery systems or have a question for our team? Connect with us at an upcoming industry event:

• November 10-11: Sustainable Ag Expo in San Luis Obispo
• November 19: Blue Diamond Annual Grower Meeting in Modesto

NOW Mating Disruption Solutions 

Puffer NOW Ace

• Delivers a precise dose of pheromone for season-long control of navel orangeworm in nut crops.
• Rebates and early order programs are available to reduce input costs for growers. 
  • Contact our customer experience team at customercare@suterra.com for more information or visit www.suterra.com/rebate. 

• Ideal for harvest operations and worker safety given its zero PHI, 4-hr REI, and MRL-exempt status. 
• Long-acting formulation protects against damage in late-shake pistachios and reduces overwintering navel orangeworm populations.
• Early-season application next Spring will keep populations low from the first flight, making any insecticide applications more successful.
• New for 2026, Suterra is offering a grower rebate for operations that apply three sprays to the same acreage. Total investment after rebate for a three-spray seasonal program is just $79 per planted acre. 

October 2025 

California’s nut crop orchards are nearing the end of their harvest season. Almonds have wrapped harvest up for the most part, while pistachios are in the middle of shakes. For growers, the urgency of harvest activities is quickly followed by planning for the next season. 

Almond Updates

Almond orchards in California are finishing harvest on late varieties. Timely removal of nuts, in this case from orchard floors, is important to prevent ant feeding, aflatoxin contamination, and further losses in crop quality due navel orangeworm feeding. With the bulk of harvest out of the way, growers can begin to focus on nutrient management to replenish trees for next year’s growing season. Growers can also begin mummy nut surveys to determine which areas of the field to focus their winter sanitation efforts.

Pistachio Updates

Pistachio harvest is bustling this month, with shakers and haulers working overtime to collect this season’s crop. At this point in the season hull slip percentages in nuts are high, which means the quicker they’re harvested, the less navel orangeworm damage. Growers should keep an eye on areas with heavy nut staining, mealybug activity, or other types of insect damage. Harvesting these areas sooner may help prevent losses in crop quality and determine areas of focus for next season.

Key Production Considerations

• Postharvest Sanitation: Begin surveying almond orchards for mummy nuts and planning winter sanitation programs. Identify areas of historically high pressure or those with large numbers of mummies to prioritize. 

• Navel Orangeworm: Continue monitoring pistachio blocks through the end of harvest to minimize late-season damage. In both crops, evaluate this season’s integrated pest management program using harvest samples to guide adjustments for next year.

• Gill’s Mealybug: As harvest continues, keep an eye on historically infested orchards. Postharvest is a good time to examine population pressure and map areas for targeted management next season.

• Tree Recovery: After harvest, replenish orchards with nutrient applications to support bud development and ensure tree health heading into dormancy

• Cover Crops: Consider planting cover crops to improve soil health and increase pollinator habitats in the spring. 
• Pruning: Avoid pruning damaged branches from trees before rainfall events as this leads to the rapid spread of disease.

From the Field 

Photo: Celeste Torres, Suterra, Technical Content Marketer

• Isaac Bocker (Field Service Representative Lead) and Collin Scholl (Key Accounts Manager) worked with growers at an orchard in Kern County to collect late-season almond varieties. Damage assessments done on these final varieties help give a more complete picture of this season's insect damage.

Suterra Speaking Events

Photo: Emily Symmes shares the advantages of drone applications of sprayable pheromones for control of NOW. 

Interested in hearing us talk in depth about our pheromone delivery systems or have a question for our team? Attend one of our presentations at the dates listed below:

• October 19th-21st: CAPCA Annual Conference in Reno, Nevada:
  • Suterra's Emily Symmes, Ph.D., will present on the main stage regarding the future of pheromones in the context of drone application technology.
  • Haydn Lenz will also present a label update on CheckMate VMB-O, an organic formulation of our sprayable pheromone for control of vine mealybug.

NOW Mating Disruption Solutions

Puffer NOW-Ace

• Delivers a precise dose of pheromone for season long control of navel orangeworm in nut crops.
• Rebates and early order programs available, contact our customer experience team for more information. 

CheckMate NOW-F

• Ideal for harvest operations and worker safety given its zero PHI, 4-hr REI, and MRL-exempt status. 
• Long-acting formulation protects against damage in late-shake pistachios and reduces overwintering navel orangeworm populations.

September 2025

California's nut crop orchards are full of activity as harvest season continues. Despite a staggered harvest window for almonds and pistachios, one thing is certain for both systems: removal of nuts must be carefully timed to avoid losses in crop quality. 

Almond Updates

Almond orchards across California are well into harvest, with many growers finishing up their Nonpareils and moving into pollinizers. Getting trees shaken and crop removed from the orchard floor in a timely manner are both crucial to preserving nut quality. Prolonged amounts of time in trees or on orchard floors increases the likelihood of navel orangeworm damage, aflatoxin contamination, hull rot, and ant feeding.

Pistachio Updates

Pistachio orchards have begun harvesting. Pistachio hulls naturally degrade as nuts ripen, which signals harvest time for growers. Because hull slip percentages are high in major production areas, the sooner the crop is harvested, the less exposure to navel orangeworm and other orchard pests. This is especially true for early-splitting varieties such as Golden Hills or Lost Hills. As nuts are collected, growers should keep and eye out for nut staining and insect damage.

Key Production Considerations

• Post-harvest sanitation: As harvest comes to a close, growers should begin to plan for post-harvest sanitation. Winter mummy removal is one of the most effective strategies to reduce NOW pressure in the next season.
• Navel orangeworm: Continue evaluating almond harvest samples to assess the effectiveness of this season’s IPM plan. Monitor populations closely in pistachios and apply last minute sprayable pheromone treatments to lower populations throughout harvest.
• Gill's Mealybug: Populations can easily be spread from field to field via harvest equipment and bins. Keep in mind which fields have historically high pressure in order to avoid cross contamination among fields during harvest

From the Field 

Video: Celeste Torres, Suterra Technical Content Marketer

• The Suterra team has been hard at work in almond orchards throughout the year. With our trial season coming to a close, the team came together earlier this month in the Kern County area to collect Nonpareil samples for a "crack out" damage assessment. 

Suterra Speaking Events 

Photo: Celeste Torres, Collin Scholl, and Keith Mioni at American Pistachio Growers' second annual Pistachio Insights Day in Visalia, CA.

• Suterra has been at the forefront of mating disruption research and development for four plus decades. Interested in hearing us talk in depth about our pheromone delivery systems or have a questions for our team? Attend one of our presentations at the dates listed below:
   
  • 9/12 CAPCA Central Valley Label Update: Modesto Junior College Ag Pavilion, Modesto, CA. Register Here
  •  9/18 CAPCA Ventura Fall Continuing Education Day: 10269 Telephone Rd, Ventura, CA. Register Here
  • 10/19-10/21 CAPCA Annual Conference in Reno, Nevada: Suterra's Emily Symmes, Ph.D., will present on the main stage regarding the future of pheromones in the context of drone application technology. Haydn Lenz will also present a label update on CheckMate VMB-O, an organic formulation of our sprayable pheromone for control of vine mealybug.

CheckMate NOW-F at Harvest

Photo: Maintain NOW control in pistachios by applying mating disruption throughout harvest.

• CheckMate NOW-F is ideal for protecting crops during harvest time given its zero PHI, 4-hr REI, and MRL-exempt status. 
• As a harvest spray, this long-acting formulation protects late shakes in pistachios, reducing potential overwintering navel orangeworm populations.

August 2025

California nut crops are headed towards the final stretch of the growing season. While nut development is almost complete and harvest activities are beginning, late-season pest pressure remains a top management priority.  

Almond Updates

Almond orchards throughout California are deep into hull split, with  harvest already starting in some regions. As machinery enters the field, keep in mind that timely harvest can immensely help protect against crop quality losses, pest damage, and hull rot.

The longer almonds stay on trees, the more susceptible they are to navel orangeworm damage because their shells remain exposed for egg laying and aflatoxin exposure. Once shaken from trees and windrowed, it is also important to move nuts from orchard floors to prevent ant damage.

Pistachio Updates

California pistachios are nearing maturity, with kernel fill wrapping up and harvest preparation underway. As hulls begin to soften and produce early splits, it’s a good idea to monitor for navel orangeworm activity, especially in early-splitting varieties (Golden or Lost Hills) or high pest pressure areas.

Trap counts and degree-day models may help pre-harvest NOW insecticide or sprayable pheromone applications. Growers should also watch for late-season activity of Gill’s mealybug on pistachio clusters. If second-generation crawlers were not adequately treated, populations may increase in August.

Key Production Considerations

• NOW: In almonds, collect harvest samples to evaluate your integrated pest management program. In pistachios, monitor pest populations accordingly to time any last-minute insecticide or sprayable pheromone treatments. 
  
• Gill's Mealybug: Scout pistachio clusters in historically high-pressure blocks, consider late-season treatments depending on population levels. 
• Harvest Prep: Monitor nut maturity and hull split to time shakes accurately, coordinate with processors to reduce delays. 
• Sanitation Planning: Start mapping blocks for mummy counts, as winter sanitation is one of the most effective NOW control strategies.

From the Field

CheckMate NOW-F at Harvest

Photo: Maintain NOW control by applying mating disruption throughout harvest.

• CheckMate NOW-F is ideal for protecting crops during harvest time given its zero PHI, 4-hr REI, and MRL-exempt status. 
• As a Harvest spray, this long-acting formulation protects almond pollinizers and late shakes in pistachios, reducing potential overwintering navel orangeworm populations.

July 2025

The start of July marks a turning point for California’s orchards. With harvest approaching fast, growers are juggling peak pest pressure, kernel development, and the final decisions that will shape this season’s yield.

2025 California Almond Forecast 

According to the USDA-NASS May 2025 forecast, California’s almond crop is projected at 2.80 billion pounds, up 3% from last year’s final total of 2.73 billion. Yield is expected to average 2,010 pounds per acre across 1.39 million bearing acres. While early-season weather included rain, wind, and hail that impacted bloom in parts of the San Joaquin Valley, March weather conditions helped accelerate development. The forecast predicts nonpareil yields may be lighter due to reduced flower set, but overall crop conditions are strong.

Almond Updates

Almonds are entering hull split across much of the state, a key phenological marker and a crucial moment for Integrated Pest Management. At this point, in-season nuts are most susceptible to navel orangeworm damage, so precision treatments are essential.

Growers should consider applications of sprayable mating disruption and traditional insecticides tailored to local degree day models and monitoring data. Because harvest is only a few weeks away for early varieties, July is the time to finish strong and minimize in-season pest damage.

Pistachio Updates

Pistachios continue kernel fill in July. For the most part, shells have completed hardening, and kernels are steadily accumulating carbohydrates, oils, and proteins. Research from UC IPM shows nutrient uptake is helpful, with targeted sprays of potassium or other micronutrients able to supplement quality nut development.

Insect pressure continues to rise, especially in warmer regions where Gill’s mealybug and mites thrive in dry, dusty conditions. Gill’s mealybug feeding can reduce tree vigor and leave sooty mold on pistachio clusters. Dust control and selective treatment can help reduce outbreaks.

Key Considerations

• Navel Orangeworm: Monitor traps and degree day models, align treatments with hull split.
• Gill's Mealybug: Scout regularly and watch for hot spots near clusters.
• Heat Stress: Monitor for leaf turgor and signs of stress as heat intensifies.
• Harvest: Finalize logistics (e.g., equipment, crews, and shaking schedules).

CheckMate NOW-F at Hull Split

Growers can improve NOW control by spraying CheckMate NOW-F at least twice per season.

The longevity of CheckMate NOW-F makes it ideal for protecting in-season crop, especially given its MRL-exempt status. Growers receive a significant return on investment by applying throughout hull split or harvest.

• Hull Split Spray: Protects vulnerable in-season crop during hull split with up to 4 weeks of flexible, effective coverage.
  
  
• Harvest Spray: Safe around harvest (0 PHI, 4-hr REI), protects late shakes and pollinizers, and reduces overwintering NOW.

December CEU Events

Continuing education is necessary to stay informed, maintain certifications, and grow expertise in your specific crop system.  

We’ve curated a list of this month's in-person and online Continuing Education Unit (CEU) events with opportunities to learn more about effective pest management strategies in California crop systems.

• Sacramento Valley
• Northern San Joaquin Valley
  
• Central Coast
• Southern California
• Webinar/Virtual

There are no pest management CEUs available this month in the Southern San Joaquin Valley  or North Coast this month.

Thanks for choosing Suterra as your partner in sustainable pest management.