The almond and pistachio seasons have delivered a tale of contrasts. Market improvement and a near-record crop were positives for almond growers, while poor pollination, blanking and sharply lower production challenged the pistachio season.
The endurance required to finish the season should be matched by foresight in taking the right steps after harvest. The work that pays off next fall starts now. Your trees have expended tremendous energy, and an effective post-harvest nutrition program is an important part of their recovery and preparation for the season ahead.
At Redox Bio-Nutrients, our focus is helping growers get more from their nutritional programs. RAM Technology is the cornerstone of our product line and functions as a plant performance support system rather than a single product or quick fix. By supporting the natural processes plants use to manage energy, maintain balance and use available nutrition, RAM Technology helps orchards recover after harvest and prepare for the season ahead.
Here are strong building blocks to a post-harvest recharge for your orchards:
Provides a comprehensive nutrient package with biostimulants that support soil health, stress resilience and root growth. This post-harvest nutritional infusion helps replenish the plant and prepare it for the season ahead.
Uses patented botanical-extract technology to support nitrogen metabolism inside the plant. By supporting the natural processes that assimilate nitrogen and convert it into amino acids and other essential compounds, RDX-N helps plants make more efficient use of available nitrogen – supporting yield potential, crop quality and overall plant performance.
Supports carbohydrate storage and utilization for continued plant performance. With zinc and boron, it supports cell structure, sugar metabolism, stress response and long-term orchard productivity.
These products are easy to store, blend friendly and effective at very low rates – built to fit into the operation you already run, not complicate it.
You put in the long hours, early mornings, late nights and weekend labor that got this year’s crop across the finish line. Give your orchards the recovery they’ve earned and give next season the head start it deserves. Reach out to me or your Redox agronomist today about building a post-harvest plan that positions you for success in 2027 and for years to come.
Jeremy Hamlin is an agronomist in the Southern San Joaquin Valley for Redox Bio-Nutrients. He can be reached at jeremy.hamlin@redoxgrows.com or (559)737-2334.
Recent studies conducted by scientists at UCCE and CSU Bakersfield demonstrate that a common disease prevalent in vineyards and orchards may impact long-term orchard longevity of almonds in the southern San Joaquin Valley.Almond orchards with a high incidence of crown gall, a disease caused by a ubiquitous soilborne pathogen, exhibit high rates of tree failure caused by a newly identified wood rotting disease.
Crown gall is common in walnut and almond orchards and can be readily identified by the tumors it induces on the roots and crowns of trees. Unless severe, crown gall generally does not cause tree mortality, but may limit tree size, thus affecting overall yield.Growers with crown gall-affected orchards often replant young trees that exhibit girdling by the tumors but leave mature trees untreated. Within the past decade, however, growers have noticed heightened prevalence of tree mortality due to butt rot in crown gall-affected almond orchards. The butt rot disease is caused by an introduced fungal pathogen, Ganoderma adspersum, that was first reported in California in 2016.
From 2024 through 2026, UCCE researchers have surveyed over 23,000 almond trees in Kern and Tulare Counties, documenting prevalence of both butt rot and crown gall.Molecular identification of the butt rot pathogen in each surveyed orchard was conducted by scientists at CSU Bakersfield. The study found that Ganoderma adspersum was the only species of Ganoderma isolated in all surveyed orchards. Additionally, the results indicated that orchards with crown gall were six times more likely to have butt rot disease. Trees with historic or active signs of butt rot also exhibited 1.5 times the mortality rate of healthy trees over a 26-month survey period.
The results of this work demonstrate that the introduction of the new butt rot pathogen may elevate the importance of crown gall as a predictor of orchard longevity. The implication of this finding is that the planting of crown gall-free rootstocks during orchard establishment may be key to future reduction of risk from G. adspersum. Similarly, Mohammad Yaghmour and Elizabeth Fichtner, Farm Advisors in Kern and Tulare Counties, respectively, found that crown gall was also associated with increased incidence of thousand cankers disease on walnut.Fichtner has also reported that crown gall is related to heightened root predation by ten-lined June beetle on walnut.
The current study was conducted with support from the Almond Board of California and as a collaborative effort between UCCE scientists including Elizabeth Fichtner, Santosh Bhandari, Mohammad Yaghmour, and Raymond Mireles, and CSU Bakersfield Professor Isolde Francis and Chance Kophamer, graduate student. — Story by Elizabeth J. Fichtner, UC Ag and Natural Resources
Farmer John Chandler lamented the loss of methyl bromide for replanting an orchard or vineyard. Photo credit: Diana Gutierrez
Andreas Westphal, scientist at Kearney Agricultural Research and Extension Center in the San Joaquin Valley, organized a soil plant pathology conference that was held on March 24-26, 2026. Participants from as far away as Virginia came to learn about the latest research findings.
Chandler Farms
The first day of the conference was a field tour to three sites and then Kearney itself. After meeting at Kearney, the participants rode on a tour bus to Chandler Farms in Selma. John Chandler, his brother Tom and their father, Bill operate a diversified farm that includes almonds, grapes and citrus.
Soil Fumigants
The Chandlers typically change out one field per year. John lamented the loss of methyl bromide for replanting an orchard. He now uses Telone, which he finds “has less effect but still works.”
He always contracts out his Telone application because it requires special training. He has the contractor put tarps over it, beyond the usual seal, to prevent off-gassing, but he says, “It’s not worth it to get acres of plastic.” The tarps add about $1000/acre to the cost.
Westphal explained, though, that Telone is becoming more difficult to use because of a new restriction in the amount of Telone allowed plus a requirement that the fumigant be applied with lots of water. The new regulations say that the soil has to be wet to two feet depth. If the soil is bone dry, three inches of water must be added within 72 hours before applying the fumigant.
However, the excess water makes it hard to get a tractor through the field. Also, the fumigant does not move well through water, as it is made to move through air. Lastly, the Telone stays in wet soil longer before vaporizing off, which may make it toxic to plants.
Nematodes
Chandler said that his farm has nematodes —the microscopic roundworms that feed on plant roots. His soil has root-knot, lesion, ring and citrus types of nematodes.
When he can afford it, he fallows the land for a year or two instead of fumigating, but he says that fumigation gives the plants the best chance to get started. Once the crop is established, he notes, there are few tools for nematode adjustment.
Burchell Nursery
The second stop was Burchell Nursery in Fowler, where Mauricio De Almeida led the group around the almond, stone fruit, citrus, pomegranate, and retail table grape plants.
Mauricio de Almeida led the tour group around the almond, stone fruit, citrus, pomegranate, and retail table grape plants at the Nursery. Photo credit: Diana Gutierrez
What is gnawing the plant roots?
Almeida said that, as in all greenhouses, the water, heat and humidity may induce root rot and fungus gnats. The fungus gnat larvae eat the soft tissue of plant roots. The adults do not feed on plants.
Another larva that Burchell manages is that of the European pepper moth. The caterpillars girdle the plant stem below the soil line.
The root rot and insect pests occur even though the potting media — made of peat, bark, wood fiber and sometimes Perlite — comes pasteurized. The nursery uses Nemasys® beneficial nematodes to manage the larval insect pests.
Almonds
In almonds, Bright’s Hybrid 5, Hansen and Viking rootstocks and Shasta scions resist root-knot nematode. Viking and Shasta also tolerate ring nematodes. Bright’s Hybrid also has low susceptibility to root lesion nematodes. In susceptible varieties, root-lesion nematodes create lesions that can lead to secondary infections like bacterial canker.
The visitors got to see the Cornerstone cultivar of Prunus rootstock, developed by Burchell Nursery to resist the root knot nematodes Meloidogyne javanica and M. incognita. Used as rootstock for almond and stone fruits, Cornerstone is also less sensitive to crown gall, caused by Agrobacterium tumefaciens.
Unfortunately, in both Kern and Merced counties (but not Fresno County where the tour took place), in 2018 a root-knot nematode from Florida, Meloidogyne floridensis, was found in almond trees on Hansen 536 and Bright’s Hybrid 5 rootstocks, where they caused growth decline of the trees. Now considered an A-rated (“highest concern”), quarantined pest in California, it has since been found in South Carolina and Georgia, after being considered endemic to Florida before 2018.
After a visit to the Cobblestone citrus packing plant, the tour group boarded the bus a final time to return to the Kearney Agricultural Research Center and ate sandwiches for lunch. They then rode on a tram to visit different field research plots at the Center.
Levels of Plant Response to Pathogens
Plants can be divided into three groups of responses to nematodes and other pathogens: sensitive, tolerant and resistant. Tolerance allows for high nematode populations, which gives the nematodes more opportunity to have genetic mutations that enable them to overcome the plants’ resistance. Therefore, nematicides should be used in tolerant cultivars to limit the pest population.
Walnuts and Almonds
Walnuts are sensitive to some nematodes and resistant to others, but “every plant has its limits,” Westphal said. Walnut soil is treated pre-plant and at-plant at the planting site. Tank water is used to settle the tree in. Salibro is added to the tank water to form a concentration that kills the nematodes but not the trees. Westphal cautioned growers to not overwater walnuts.
Among other things, Westphal is testing juice from walnut hulls to see if they inhibit nematodes. He noted that ASD (anaerobic soil disinfestation), created by applying nine tons of rice bran per acre, inhibited nematodes somewhat. However, it would not be worth the $6,000/acre price tag for growers.
Westphal is testing whether juice from walnut hulls can inhibit nematodes in almond orchards.
Highly resistant rootstocks can grow without fumigation, with less toxic, affordable nematicides applied. As with citrus, nursery trees must be grown in nematode-free soil, or the trees must be certified before leaving the premises.
Westphal showed the tour participants an almond rootstock test orchard, in which nematode resistance is compared among various commercial and experimental rootstocks. Only the most successful experimental rootstocks make it to the next round of trials, along with the commercial ones for comparison.
Westphal then concluded the field tour. The conference continued indoors on the following two days. — by Nancy Power, Assistant Editor
With all the new pistachio acreage coming into production in the San Joaquin Valley, it was no surprise that growers experienced their largest crop ever last year; some may have been surprised however, that even in an off-year, growers have still managed to produce the second largest crop on record. Watch this video interview with Richard Matoian, Executive Director of American Pistachio Growers, as he shares more details on the size & quality of the crop. Be sure to also attend the Grape, Nut & Tree Fruit Expo on November 14 for Matoian’s annual State of the Pistachio Industry report.
Jeremy Hamlin is an agronomist in the Southern San Joaquin Valley for Redox Bio-Nutrients. He can be reached at jeremy.hamlin@redoxgrows.com or (559)737-2334.
