MARCH 2023 ISSUE
SPOTLIGHT ARTICLE: PISTACHIO TRAINING TRIAL OFFERS PRODUCTION RESULTS
SEE PAGE 38
IN THIS ISSUE:
WALNUT GROWERS FEEL THE HEAT ON QUALITY
SEE PAGE 4
OCEAN SHIPPING AND LOGISTICS ON THE MEND AFTER MAYHEM
SEE PAGE 8
TRANSFORMING
DEVELOPMENT OF NEW ALMOND ROOTSTOCK
SEE PAGE 28
BY REAL CALIFORNIANSSince 1933, Rain Bird has pursued the most water-efficient and innovative irrigation technology in the world. We began with the original horizontal action impact drive sprinkler and followed it up with over 450 patents that continue to shape the future of irrigation. Looking for a better long-term irrigation forecast? Visit rainbirdag.com.
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Almond Board of California
Contributing Writer
Annette Betts
CSIRO Agriculture and Food, Waite Campus, Adelaide, South Australia, Australia
Vicky Boyd
Contributing Writer
California Walnut Board and Commission
Contributing Writer
Hazelnut Marketing Board, Contributing Writer
Pat Iocco-Corena
CSIRO Agriculture and Food, Waite Campus, Adelaide, South Australia, Australia
Roger A. Isom President/CEO, Western Agricultural Processors Association
Julie R. Johnson
Contributing Writer
Tanya Kovalenko
CSIRO Agriculture and Food, Waite Campus, Adelaide, South Australia, Australia
Rich Kreps
CCA, SSp., Contributing Writer
Mitch Lies
Contributing Writer
Debra McDavid
CSIRO Agriculture and Food, Waite Campus, Adelaide, South Australia, Australia
Catherine Merlo
Contributing Writer
Melissa O’Neal, Ph.D., Senior Product Development Manager, ProFarm Group, Inc.
Harley Smith
CSIRO Agriculture and Food, Waite Campus, Adelaide, South Australia, Australia
Mike Wade California Farm Water Coalition
Jhalendra Rijal
UCCE Integrated Pest Management Advisor, Stanislaus County
Mohammad Yaghmour UCCE Area Orchard Systems Advisor, Kern County
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Pistachio tree training and staking trials look to bring pistachio trees into production more rapidly, at a lower cost while improving water use efficiency and establishing a strong tree structure.
See page 38
By CECILIA PARSONS | Associate Editor
In a tough price year, walnut quality becomes paramount for growers. Large, light-colored kernels free from insect damage and mold garner the best returns, but in 2022, the ideal was elusive for many walnut growers.
At the 51st annual Tri-County Walnut Day held in Tulare, Calif., UC researcher Bruce Lampinen said that with increasing temperatures and uncertain water availability, walnut quality is going to be an increasing problem for growers, particularly in the southern San Joaquin Valley, but statewide as well.
Overirrigation or underirrigation, walnut husk fly, navel orangeworm, blight, Botryosphaeria (Bot) and Phomopsis are all known to have negative impacts on kernel quality. In 2022, it became evident that excessive daytime temperatures at critical walnut development stages can also impact walnut quality.
Lampinen said walnut quality has
been decreasing in recent years with blocks of higher-value varieties Howard, Tulare and Chandler delivering higher percentages of dark kernels. In-shell weights, indicative of kernel percentage and/or nut size, have also been decreasing. Lampinen as well as other researchers, growers and walnut industry leaders said environmental causes, specifically high temperatures at critical stages of nut development, are causing quality issues. With the 2022 harvest, damage was widespread. He said many nuts had damaged hulls on one side likely due to the September heat spell. Since the nuts were already at ambient air temperatures of 111 degrees F and higher, any nut in the sun at the warmest time of day in early afternoon could have reached 122 degrees F, the temperature at which pellicle damage occurs.
Joe Grant, California Walnut
Board director of research, said water stress, low carbohydrate levels and
“Timing of stress has different impacts on the crop. Stress from late August to hull split in September causes dark kernels.”
– Bruce Lampinen, UCCE
sunburn all impact walnut quality, but 2022 was a particularly bad year due to high heat in early-September.
“About two to three weeks earlier than normal hull split starts, the hulls of some nuts, usually in low and interior canopy positions, develop a ‘shattered glass’ appearance. Then they turned black and adhered to the shell,” Grant said.
Lampinen in his presentation said nuts that have hulls that do not split normally maintain wet conditions around the kernel and cause it to darken.
Willows walnut grower Leslie Nerli said at first she thought the unusual hull appearance was due to latent blight. There was no pattern to the damage, but she said it became obvious after a heat spell in early September.
She said nut samples were sent to Plant Pathologist Themis Michailides at the UC Kearney research center to
determine the cause of the blackened hulls.
Michailides said Nerli was not the only walnut grower to contact him with concerns.
“I received a lot of requests to come to the orchards and look at this problem, and my first impression looking at the nuts is that when opened, they looked ‘cooked’,” he said.
To determine exact cause of the blackened, adhering hulls, Michailides said samples showed high levels of pathogens, including Alternaria, Fusarium, aspergillus niger and Botryosphaeria, but he believed those pathogens were secondary to the heat damage. As the affected hulls deteriorated, he said the hull tissue was killed and the pathogens moved in fast to colonize the dead tissue.
Some inside kernel mold was also found in the samples. He reported in Sac Valley Walnut News that the high mold
incidence was worsened by the rainfall following the heat wave. The hull rot also stopped the hull split process, causing the black hulls at harvest, dark kernels and high huller and processor rejection levels. Michailides said the high heat occurred when the oil in the kernel was most susceptible to damage.
Nerli said Michailides came to her orchard and took nut samples back to the lab for testing. Her 2006 planted Chandler block had three previous years of at least 92% light, and total mold was never above 2%, nor was total serious for the final grade average above 2%. Last year, she said for that block, the average light count was 64% with a mold count of 4% and a serious average of 5%.
Nerli said besides the 2006 planting, she has blocks planted in 2012 and 2018. Spacings are the same in all three blocks. They are sprinkler-irrigated, and a pressure bomb is used to determine irrigation timing.
She said the trees were sprayed with Surround, and Bot, Alternaria and blight spray treatments were done, but these didn’t improve the black hull situation.
“With the grades we have from both sunburn and the black nuts under the canopy that I believe worsened over the summer with the high heats, coming on at different times within a single orchard from July through September, it will be tough to market. Yields were
“I received a lot of requests to come to the orchards and look at this problem, and my first impression looking at the nuts is that when opened, they looked ‘cooked.”
– Themis Michailides, UC Davis
up, but quality was a disaster.”
Lampinen said he has previously conducted field trials involved tagging and monitoring of individual nuts on the tree to assess environmental and canopy position impacts on quality. Lampinen said light was measured over the course of the day and leaves were sampled to assess leaf specific mass. Leaf area and in-shell and kernel weights were measured at the time of harvest. Low leaf specific mass is a result of low light conditions, and results in kernel quality problems, he said, and spurs that have lost leaves tend to have nuts with discolored hulls.
“Timing of stress has different impacts on the crop. Stress during May to June impacts nut size. Stress during July and August, when kernels fill, can impact size and cause shrivel. Stress from late August to hull split in September cause dark kernels,” he said.
The trial also included a look at four degrees of hull split or lack of hull split. The black and shattered nuts generally
are in the lower canopy he said and are normally related to insufficient light and leaf area and generally only impact 5% or less of the nuts on the tree. Lampinen said that much of the 2022 quality problems were likely caused by other factors. One factor is overirrigation as Lampinen reported seeing more severe black nut damage in wetter orchards.
The trials also showed that most sunburn occurred in the lower positions on the southwest side of the tree where there was an indentation in the canopy, likely leading to lack of air circulation. Since sunburn has historically been known as a cause for diminished walnut quality, Lampinen said numerous trials have looked at use of kaolin clay products applied by sprayer. Kaolin products should be used, he said, if beneficial for pest management or sunburn, but it will not reduce water stress. Kaolin coverage needs to be concentrated on nuts that are in the sun from 1 p.m. to 2 p.m.
Lampinen said trials also showed that kaolin treated trees were more stressed that untreated trees, most likely because stomata stayed open on the cooler kaolin treated leaves longer, resulting in more stress.
Citing numerous walnut quality studies done over the years, Lampinen said that kaolin treatments are unlikely to have much beneficial impact in years like 2022. Growers who plan to use kaolin should walk through the orchard from 1 p.m. to 2 p.m. Nuts that are in the sun at that time should be targeted for the treatment.
Lampinen said adequate soil moisture is important, but orchards should not be excessively wet approaching harvest. Do not, he warned, apply a big irrigation right before a severe heat event.
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Strategic planning is all about defining our desired future and developing a plan to help achieve it. This process is designed to be robust and inclusive, as I believe the best made plans are rooted in collaboration—and we can’t do it without you.
Thank you in advance for your time and for the honor of serving as stewards of your investment.
Robert Verloop CEO/Executive Director California Walnut Board and Commission
For international freight-forwarding executive Bill Rooney, the logistics and shipping crisis of 2021-22 was the worst experience of his lengthy career.
“If I added up all the mayhem over 50 years in the shipping business and multiplied it by five, it would not come close to what the world has gone through in the last three years,” said Rooney. “It has been astounding in its severity, and it has affected everybody.”
Rooney is vice president of strategic development for Kuehne+Nagel, one of the world’s leading sea, air, road and contract logistics companies. Based in Switzerland, it counts over 80,000 employees at 1,300 locations in over 100 countries, including the U.S.
Kuehne+Nagel has a dedicated sea freight service, Dried Fruit & Nuts Sea Logistics, or DFN, which handles West Coast tree nut shipments. Knud Meyer
is DFN’s global development manager. Rooney and Meyer shared their perspectives with West Coast Nut, underscoring the unprecedented impact of the pandemic-fueled shipping crisis and forecasting what tree nut growers, handlers and exporters can expect in the months ahead.
Q. What were some of the most extraordinary aspects of the logistics and shipping crisis of 2021-22?
Rooney: Global rates were up by a factor of five. All logistics activities, from the physical movement of cargo to administrative actions and things in between, were taking two to three times as long. Approximately 15% of global vessel capacity was absorbed by congestion. Unprecedented cargo volume growth challenged availability of logistics assets in the U.S. All major
Despite improved ocean shipping and logistics, problems remain with schedule reliability, says
ports in the world had ships waiting for berthing space. The highest number for Los Angeles and Long Beach was 109 ships waiting.
Q. How has the ocean shipping situation changed in the last six months? What’s improving, what’s not, especially for moving West Coast tree nuts overseas?
Rooney: For the non-nuts portion, things have improved a lot but are not
yet fully back to pre-COVID levels. Congestion has eased significantly but
has to get back to pre-COVID levels. There is no longer a container shortage. For the portion of tree nuts shipped mainly from the U.S. West Coast, the situation has improved significantly.
Last year, we saw congestion with over 100 ships waiting off Oakland and Los Angeles. The situation has since returned to normal. Services are more reliable again, scheduling is much easier and more capacity is available again on weekly departures. Right now, we are seeing some equipment challenges, especially for the Oakland area. Less equipment has come to Oakland due to lower volumes from Asia.
What is your outlook for the logistics and shipping industry?
Rooney: Global trade growth in 2023 is likely to be flat or up very little or even down up to 2%. In my opinion, 2023 will affect the speed of the global fleet to meet new environmental requirements. The new regulations will effectively lower fleet-wide capacity by up to 15%. Carriers’ ability to control capacity, and thereby rates, via blank sailings is a significant unknown at this point.
Meyer: Blank sailing is when an ocean carrier cancels or skips a scheduled port in the middle of a fixed rotation. Currently, we see them especially at Oakland, which leads to challenges with equipment availability.
Q. Labor uncertainty continues at West Coast ports. What are the main issues, and how are they affecting shipments to and from West Coast ports?
Rooney: The main issues in West Coast labor, primarily through the International Longshore Warehouse Union (ILWU) and the Pacific Maritime Association (PMA), are:
Automation. The ILWU does not want to allow terminal automation because it will cost them highly paid jobs.
Union jurisdiction. The ILWU wants to take on mechanics jobs in the ports that are currently represented by the machinists union.
Money. The ILWU will want higher salaries and more expensive benefits. The ILWU-PMA contract expired on July 1, 2022. Negotiations began on May 10, 2022 and continue with no
agreement up to this point [late January 2023]. Some sources believe that an agreement will not be reached until March of this year or later. The impact
We can see the situation for ocean freight is going back to normal. The lower volumes, however, also challenge the equipment availability.
– Knud Meyer, Dried Fruit & Nuts Sea Logistics
on logistics is that a significant amount of cargo has moved from the West Coast to the East and Gulf coasts.
Rooney: Cargo volume globally declined by about 22% in late 2022 vs. 2021. Demand is down for three reasons:
In the U.S. and to an extent worldwide, consumer spending patterns are
returning to pre-COVID norms. Before COVID, U.S. consumer spending was split 70%/30% on services and products. During COVID, the split went to about 66% for services and 34% for products. Spending is now moving back to the 70%/30% split.
Inflation has affected consumers’
ability to buy products, which shows up in lower cargo volume.
Lower economic activity. Global GDP growth in 2023 is expected to be about 2%. Lower GDP growth means lower trade and volume growth.
Q. What can almond and other tree nut exporters expect in the coming months regarding their shipments?
Meyer: The last two years have been challenging for all participants in the dried fruit and nuts market. This underlined how important good relation-
ships with logistic partners are. We can see the situation for ocean freight is going back to normal. The lower volumes, however, also challenge the equipment availability. Import cargo is generally destined for the more populated urban
distribution areas while the dried fruit and nuts exporters are in the valley and more rural areas, creating a natural imbalance of equipment. Schedule reliability is still low compared to preCOVID times. But we are also seeing improvements, which is good news for tree nut exporters.
Q. Many people believe 2023 will see a slowdown in the global economy. How would that impact ocean shipping?
Rooney: Slowdown of GDP growth in 2023 could mean recessions in the U.S. and Europe. This will drive lower cargo volume globally. Lower cargo volume will mean congestion and related factors should no longer be an issue.
Q. What has Kuehne+Nagel learned from the shipping crisis?
Rooney: Everything I have said above plus carrier ability to control vessel capacity in real time will likely define the future of rates to move cargo. There is not likely to be a shortage of assets (ships, terminals, chassis, trucks, trains, rail rams) in the near-term future.
Q. Are you confident the Ocean Shipping Reform Act of 2022 will help the logistics situation?
Rooney: The Federal Maritime Commission is implementing OSRA
2022, which was signed into force by President Biden on June 16, 2022. The act will likely improve exporters’ access to purchasing assets and improve some aspects of transportation, such as clarifying the earliest return date. It will also improve and clarify the application of detention and demurrage charges. OSRA will give the FMC more enforcement authority over ocean carrier actions and define when ocean carriers practice unreasonable refusal to deal when denying to transport export cargoes. In summary, OSRA should make exporting cargo from the U.S. easier.
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For the portion of tree nuts shipped mainly from the U.S. West Coast, the situation has improved significantly.
– Bill Rooney, Kuehne+Nagel
By HAZELNUT MARKETING BOARD | Contributing Writer
Close to 600 growers, exhibitors and industry leaders gathered to discuss the 2022 harvest and learn what lies ahead in 2023 at the 108th Nut Growers Society of Oregon, Washington and British Columbia Winter Meeting.
One of the primary goals of the Winter Meeting is grower education, helping farmers discover new production methods or the latest news on all aspects of the hazelnut industry. To this end, the 2023 informational seminars addressed several key issues applicable to the modern hazelnut farm.
After the annual business meeting and opening ceremonies, Nik Wiman with Oregon State University Extension delivered his presentation on the pros and cons of irrigation vs dryland farming in hazelnuts.
Colleen Nihen, executive director of the Oregon Hazelnut Industry Office, provided some insight into the ongoing hazelnut marketing efforts being led by the Hazelnut Marketing Board. This included how current promotional efforts are laying the groundwork for future initiatives. Among the biggest “wins” for 2022 was the inaugural Oregon Hazelnut Tour, which brought 25 buyers from across the U.S. to learn about hazelnuts. The ongoing MAP, ATP and TASC grant programs were also highlighted.
Blinn Carstensen from Ag West Farm Credit and Jeff Reimer from the Oregon State University Applied Economics department presented on the current
global economic climate and inflation, and how these factors will impact hazelnut farmers in 2023 and beyond. Carstensen and Reimer also offered tips on how farmers can best prepare themselves for tough financial times and implement long-term strategies.
Terry Ross with the Hazelnut Growers Bargaining Association (HGBA) expounded on the factors impacting current hazelnut prices. Jenny Dresler from the Public Affairs Counsel, the lobbying group who works on behalf of the Associated Oregon Hazelnut Industries (AOHI), apprised the audience on the upcoming legislative session in Salem. Several key bills that are relevant to hazelnut farming will be up for debate, and Public Affairs Counsel will keep growers updated through AOHI.
To close the day, the NGS board of trustees shared some of the lessons they learned in 2022 on the Best Practices Panel. Each board member is an active
hazelnut farmer, representing a diverse swath of locations, orchard ages, and growing practices.
All seminars were recorded and are available to 2023 NGS members on the Growers’ Corner website, members.oregonhazelnuts.org.
A favorite Winter Meeting tradition is the award ceremony. Each year, one grower is recognized for their hard work, dedication and willingness to share their knowledge with fellow hazelnut growers. The Grower of the Year award was presented to Ron Wetzel of Carlton, Ore. A hazelnut farmer for more than 65 years, Wetzel has seen and done it all in the industry, and he has become a sage advisor to many of his neighbors and peers.
The Oregon Hazelnut Commission (OHC) Service Award is presented to retiring members of the Commission as a token of gratitude for lending their time
Nik Wiman with Oregon State University Extension delivers his presentation on the pros and cons of irrigation vs dryland farming in hazelnuts at the 108th Nut Growers Society of Oregon, Washington and British Columbia Winter Meeting (all photos courtesy Hazelnut Marketing Board.)and talents to the organization. Matt Schuster was honored this year, after serving on the OHC from 2019-22.
A special surprise honorarium was announced. Shawn Mehlenbacher, David Smith and Becky McCluskey were each recognized for their decades of work leading the Oregon Hazelnut Breeding Program at Oregon State University. All three will be retiring from full-time employment within the year. The U.S. hazelnut industry would not be where it is today without new and emerging varieties that are the backbone of a thriving industry.
Mehlenbacher, Smith and McCluskey were each presented with a custom plaque made from 80-year-old Barcelona hazelnut wood as a “thank you” from the hazelnut industry.
In addition to the educational sessions, growers enjoyed the annual tradeshow, complete with more than 60 exhibitors. From pruning equipment to sweepers to financial resources, these vendors and sponsors showcased anything a hazelnut farmer could need.
New in 2023 was the Recipe Swap. During the lunch hour, several dozen attendees gathered to discuss their favorite hazelnut recipes and share ideas for new cookies, cakes and casseroles, all starring hazelnuts. Anybody who participated in the Swap was also welcomed to enter a drawing for a goodie basket, highlighted by a private wine tasting at Willamette Valley Vineyards.
Throughout the day, guests could visit with the Oregon State University hazelnut research team in the Research Rooms. Researchers including Shawn Mehlebacher, David Smith, Nik Wiman, Danielle Lightle, Robert McGorrin, Marcelo Moretti, Jay Pschiedt, Betsey Miller and Vaughn Walton were on-hand to discuss their ongoing OHC-funded research projects; these topics range from sucker control to new variety development to pest management.
The Nut Growers Society of Oregon, Washington and British Columbia is the premier fraternal organization for the U.S. and Canadian hazelnut farmers. NGS members have access to
signature events like the Winter Meeting, Summer Tour and Catkins and Coffee as well as the NGS website and quarterly newsletter. All hazelnut growers are encouraged to join, and more information can be found at members.oregonhazelnuts.org.
Comments about this article? We want to hear from you. Feel free to email us at article@jcsmarketinginc.com
The Grower of the Year award was presented to Ron Wetzel of Carlton, Ore., hazelnut farmer for more than 65 years.
There are currently three categories of biologicals recognized by the Environmental Protection Agency: Biopesticides, biostimulants and biofertilizers. Biopesticides are derived from natural materials such as animals, plants, bacteria and certain minerals. Biopesticides can further be divided into three subcategories, including microbials, biochemicals and plant-in-
Many biopesticides are OMRI-listed and can be used in both conventional and organic programs.
corporated protectants. Microbials are made from microorganisms, such as bacteria, viruses, fungi and protozoans as well as byproducts of their fermentation process.
Chromobacterium subtsugae strain A396 and Burkholderia rinojensis strain F727 are two bacterial species that have been formulated to provide broad-spectrum activity against arthropod pests.
Biological products are highly compatible, efficacious and low-impact to beneficial arthropods.
Like many other biopesticides, these products are exempt from maximum residue limit (MRL) requirements, which alleviates MRL concerns for export of treated commodities. They also require minimal personal protective equipment due to comparatively low toxicity profiles. Most biopesticides allow a zero-day pre-harvest interval, so treatments can be made leading up to and on the day of harvest if needed. Biologicals typically offer a four-hour re-entry interval to treated areas, which allows for increased worker flexibility. Many biopesticides are OMRI-listed and can be used in both conventional and organic programs. It is essential to always refer to the product label prior to making pest management decisions, including tank mixing.
C. subtsugae strain A396 was initially discovered under a hemlock tree in Maryland. Its action is due to both chromides and proteins in the heatkilled fermentation, which contains no viable bacteria. Treated arthropods stop feeding immediately but remain moribund for days, eventually succumbing. Short-term repellency and reduction in fecundity is also associated with this biopesticide. C. subtsugae should be applied to newly hatched arthropods when the population is first noticed. It also is excellent in combination or rotation with other products.
The B. rinojensis strain A396 bacterium came from a Buddhist temple garden in Japan. It is not related to
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any human pathogenic Burkholderia species; the biopesticide fermentation is heat-killed and contains no viable bacteria. Treated arthropods cease feeding immediately due to the gut disruption action of this biopesticide, though it can take several days before death occurs. This biopesticide should also be applied to newly hatched arthropods when the population is first noticed. B. rinojensis can be used in programs with other conventional products as well as with other biologicals.
The addition of B. rinojensis and C. subtsugae to existing pest management programs can enhance control efforts of the three main arthropod pests of tree nuts: navel orangeworm, walnut husk fly and webspinning spider mites.
Navel orangeworm (NOW) is a Lepidopteran (moth) pest with a broad host range. It damages crops due to the feeding of larvae inside nuts or between hulls and shells. Larvae bore into the nutmeat, can consume most of the nut and produce large amounts of webbing and frass. Also, multiple larvae can be found feeding in a single nut. This damage can lead to fungal infections, which in turn can result in downgrading or rejection of nut crops. When aflatoxin-producing fun-
gi are present, human safety can be of additional concern. Tolerance to NOW and its damaging effects are very low, increasing the chances of export rejection.
One of the major challenges with this pest is the need for winter sanitation, which involves removal of all unharvested nuts from orchards. This is due to NOW’s ability to overwinter in nuts and cause damage the following year. However, sanitation is expensive since it is usually done by hand. Timely removal of nuts from the orchard floor is also important due to the potential for further damage. As there are only a handful of insecticides currently labeled for NOW, the potential for resistance development is high, which is where biologicals can help.
Over the past several years, ProFarm Group, Inc. (PFG) has collaborated in many studies targeting NOW with UCCE as well as private contract researchers. Research results indicate that B. rinojensis applied alone, or in programs, can be a very effective tool in NOW management.
Tank mixing biologicals with either conventional chemistries or other biologicals frequently results in enhanced control compared to the efficacy of either partner applied alone.
Typical recommendations include adding B. rinojensis at 1 quart per acre to either chlorantraniliprole or methoxyfenozide for improved control of NOW. Such programs decrease the potential for insecticide resistance by introducing multiple modes of action, leading to higher target pest mortality. Applied alone, B. rinojensis should be applied at the 2 quarts per acre rate. Application timings for NOW management are May spray, early hullsplit and a third application 14 days after hullsplit if needed. This biopesticide also provides improved management of peach twig borer and webspinning spider mites.
Walnut Husk Fly, Rhagoletis complete
Walnut husk fly (WHF), is a Dipteran (fly) pest of walnuts. Adult female flies lay eggs within the hull of walnuts, after which larvae hatch and feed within the hull. This feeding activity causes blackened areas to develop, which eventually decay and cause staining of the nutshell. WHF infestations during the early growing season can cause kernels to shrivel and mold, rendering them unmarketable. It is important to carefully monitor WHF populations and make timely treatments when flies are noted in orchards, because once eggs are laid within the hull, damage control becomes very difficult.
Past research with Dr. Robert Van Steenwyk, entomologist with UCCE at UC Berkeley, has indicated that B. rinojensis can be an effective option for WHF management programs. The addition of B. rinojensis at 2 quarts per acre to attractant bait made of hydrolyzed corn meal at 3 pints per 100 gallons, or to Molasses at 4 gallons per 100 gallons of water can help to reduce WHF infestations. B. rinojensis can also be applied as a standalone at 4 quarts per acre to manage WHF populations. Applications should be made when WHF adults are active in orchards, based on trapping observations. For additional information, please refer to the 2(ee) listed on the PFG website at marronebio.com/download/venerate-xc-2ee-
recommendation-for-managing-walnut-husk-fly-on-walnut-trees/.
Spider mites can affect a wide variety of crops. These pests can reproduce rapidly and may cause extensive damage to foliage due to their feeding habits. Mites puncture plant cells with their mouthparts, which leads to stippling and loss of chlorophyll, resulting in decreased photosynthesis. They may also directly damage fruit in many crops, leading to downgrading or rejection. Mites in the Genus Tetranychidae can produce copious amounts of webbing, which makes it harder for miticides to reach their intended target and provide effective control. Multiple generations per year paired with multiple treatments have led to older miticides becoming less effective, due to populations developing resistance.
PFG offers two bioinsecticides: C. subtsugae, which repels, stops feeding and reduces reproduction, and B. rinojensis, which functions through feeding interference and causes death by ingestion. Both products can be used alone or in combination with other conventional and biological products that are labeled for use against mites on tree nuts. Used alone, C. subtsugae is generally applied at 2 pounds per acre and in combination is used at 1 pound per acre. As a standalone, B. rinojensis is applied at 2 quarts per acre and tank-mixes are applied at 1 quart
per acre. It is best to start applications as soon as mites are noticed, ensuring thorough coverage of both sides of the leaves. The treatment interval is generally 7 to 10 days but can be shortened under high pest pressure. Use of a surfactant is highly recommended as webbing created by pest mites can hinder penetration of the spray solution onto plant surfaces.
C. subtsugae and B. rinojensis biopesticides have the benefit of being extremely low-impact on beneficial arthropods as confirmed by third-party studies. Eurofins Agroscience Services conducted an acute toxicity study over 24 hours at three times the maximum label rate for C. subtsugae and B. rinojensis. No significant mortality was observed for many beneficial arthropods across several entomological families. A chronic toxicity study of both pesticides, performed by Vineland Research Institute, resulted in no significant mortality or reduction in reproductive capacity over
96 hours in four predatory mite species. This suggests C. subtsugae and B. rinojensis can be used with minimal effect on natural enemy populations endemic to orchards, which keep both primary and secondary pest populations in check. Additionally, the products can be used along with IPM programs that utilize releases of natural enemies.
Today’s IPM practitioners have an ever-increasing set of tools to choose from, with biologicals at the forefront of new technology. Biological products are highly compatible, efficacious and low-impact to beneficial arthropods. They represent valid resources for crop management professionals to incorporate into their existing pest management programs.
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By CECILIA PARSONS | Associate Editor
There is no ‘one and done’ for this pest.
Successful efforts to minimize navel orangeworm damage in almond crops comes down to these top five strategic steps: sanitation, monitoring, mating disruption, insecticide applications and timely harvest.
Navel orangeworm (NOW) is the primary insect pest of almonds in California. In the larval stage, it bores into nuts to feed, not only damaging the kernel but introducing molds that can produce aflatoxins.
The ability of navel orangeworm, Amyelois transitella , to fly long distances and feed on many different host crops makes control in tree nut crops a challenge. In devising a control program, growers need to consider the almond varieties in the orchard, anticipated harvest dates, NOW pressure levels as determined from pheromone trapping, overwintering mummy load and proximity
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to tree nut orchards with high NOW
“Destroy with prejudice” is how Blue Diamond Grower Relations Manager Mel Machado advises almond growers to carry out orchard sanitation. Achieving good orchard sanitation can be difficult in wet years, but Machado said there really isn’t an alternative.
“This is the foundation of any control program. You cannot spray your way out of the NOW problem,” he said.
Unless orchard sanitation was done by early December, heavy rains since then may have kept growers from completing orchard sanitation. Depending on the variety, growers could have completed sanitation through the first week of February. Machado said research has shown that almond trees only keep 20% to 40% of fruiting buds, and if a few are lost with a late shake, yield loss poten-
There should be no more than one to two mummy nuts left on the tree
after the shake, Machado said. In areas where NOW pressure is higher, in south state growing regions, the threshold is even lower at half a mummy per tree.
“And no, crows won’t do the job for you,” Machado said.
Machado is a little more direct when addressing how the mummy nuts should be destroyed.
A flail mower operated at a speed where nuts are not just wounded but fully destroyed is recommended, removing protected overwinter sites.
Operation speed depends on the type of blades on the mower, how fast they are turning and the number of nuts on the ground. Machado advised picking a gear, mowing 50 feet and checking to see if the nuts are being destroyed. Slow down if nuts are not being completely destroyed.
This sanitation step can be carried out later than the shake, he said, as the NOW adults won’t emerge until April. Mummy degradation can be enhanced if they are shaken into a cover crop.
Mating
is a preventative measure meant to suppress NOW
increase mortality, Machado said, and when the crop is mowed prior to NOW emergence, the nuts can be destroyed.
Almond Board of California Principal Analyst Jesse Roseman noted that sanitation alone produces better con
Tracking phenology of NOW is the basis for treatment decisions. Considering costs of NOW control, Semios in-
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disruption (MD) in an orchard
population. Used over time, MD has the potential to reduce need for insecticide applications (photo by T. Chalstrom.)
house PCA and Entomologist Abigail Welch said precise use of insecticides is paramount.
“When you are tracking phenology, you want to hit the targeted stage at the right time to be as impactful as possible,” Welch said.
Monitoring for NOW egg oviposition is important to set biofix, which initiates degree day accumulation for that flight. This is achieved using egg traps early in the season to monitor the activity of mated female NOW. Baited wing traps can also be used to attract mated females. Pheromone traps are used to monitor adult male NOW activity but are less informative when mating disruption systems are in use. Phenyl proprionate (PPO) lures can be used with pheromone lures or nutmeal lures can be used to monitor adults under mating disruption.
Welch said the first-generation cycle from egg to adult is completed in 1100 degree days because they are feeding on mummy nuts. The second generation completes a cycle faster; in 700 degree
days given the eggs are laid on fresh nut material after hull split. This can cause a difference in when the subsequent flights will emerge, and the differences in hull split timing between almond varieties can present challenges in timing insecticide applications.
This part of NOW control is most effective when done at the right time. USDA Research Entomologist Joel Siegel said planning ahead and preparation will allow sprays to be initiated and completed at the right time.
“Buy your chemicals early, not the week before you plan to spray,” Siegel advised. With the difficulty in obtaining products in the last two years, it would be a good idea to get orchard chemicals as early as possible.
It is also important to make insecticide applications as efficient as possible. Correctly calibrating sprayers and replacing worn nozzles improves efficiency. Siegel also advised following the insecticide label and adding an adjuvant as well as reading its label.
Listening to and following recommendations of your PCA is also important. Siegel said when the recommendation is to spray July 1 and the application isn’t made until five days later, efficacy is lost. Even if the start time is on target, finishing the job in five to seven days is important. Siegel said if that cannot be done, consideration should be given to air application or adding more equipment. To achieve maximum return on spray costs, he said to spray both sides of the tree row at a speed that allows for canopy coverage.
“If ground speed is too fast, you sacrifice ability to achieve good coverage in the upper canopy,” Siegel said.
Siegel also recommended evaluating spray crew abilities and designating the most responsible person to mix the tank batches and pre-position the material in the orchard when possible, decreasing down time for the spray rig.
There are lots of good reasons to make insecticide applications at night, Siegel said, like less degradation of chemicals by UV rays, less evaporation and drift. Navel orangeworm moths are more active at night, so kill rate is higher.
Mating disruption (MD) in an orchard is a preventative measure meant to suppress NOW population. Used over time, MD has the potential to reduce need for insecticide applications.
Emily Symmes, senior manager of technical field services for Suterra, said growers who are considering adoption of this technology should speak with MD manufacturers to determine which products are the best fit for their operation.
Delivery systems for the pheromones used in MD include aerosol puffers, which are timed release, and passive release emitters that work over the entire season. The newer flowable products last 30 days after application and help with grower flexibility. Symmes said these can target specific NOW flights.
Regardless of the delivery system, Symmes said it is important to fit the system to the orchard.
There are systems that work in smaller orchards. Mating disruption can make an impact even if there is potential NOW migration into the orchard.
Almond harvest contractor and grower Matthew Efird said control of harvest timing is essential in getting the nuts out of the orchard before NOW damage occurs. Almond growers who have their own harvest machinery have more control when their trees are shaken and nuts picked up. Those who rely on a contractor need to monitor for NOW flights and make insecticide
applications when necessary to prevent damage if harvest is delayed.
Almond variety, size of operation and weather are part of the decision-making process, Efird said. The goal is to get the nuts harvested before later NOW flights. The longer the nuts remain in the orchard, the greater the risk of damage.
Risk of NOW infestation in early harvested varieties such as Nonpareil
can be reduced if nuts are harvested before third-generation eggs are laid.
Efird said almonds are ready to shake when hulls are completely split and have a yellow coloring. The further the hulls are past that point of maturity, the more difficult the almonds can be to remove.
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“When you are tracking phenology, you want to hit the targeted stage at the right time to be as impactful as possible.” Abigail Welch, Semios
Rootstocks are a sustainable tool for safeguarding orchards from pests, diseases and abiotic stress as well as altering tree architecture for diverse planting systems (Vahdati et al. 2021). However, the California almond
industry is currently facing considerable challenges with pests and diseases as well as extreme climate events (Lobell and Field 2011; Luedeling et al. 2011; Westphal et al. 2019). Unfortunately, most commercial rootstocks fail to provide a wide spectrum of pest and disease resistance and may not be suitable for new production systems in a changing climate. Further, breeding and evaluation of new perennial rootstocks is a considerable time-consuming investment. The ability to genetically modify existing and new experimental rootstocks in a targeted manner will likely increase the ability to deliver new pest- and disease-resistant and climate-resilient rootstocks in a shorter time frame.
The HORT57 Almond Board of California funded project titled “Prunus rootstock transformation for a changing climate” is focused on developing a plant regeneration system(s) for genetic transformation of new and commercial Prunus rootstocks used in almond production. Genetic transformation systems have the potential to introduce beneficial genes that function to protect trees from pests, diseases and abiotic stress into existing and/or newly bred Prunus rootstocks. In addition, genes that modify plant architecture for different tree density planting systems and reduce management inputs can also be targeted and introduced into rootstocks to increase production. Moreover, developing a Prunus transformation system will provide an opportunity to develop a gene-editing system(s) to further expand the almond rootstock breeding tool kit. Therefore, genetic transformation systems provide a pathway to introduce beneficial genes into existing rootstocks and/or edit genes without having to go through lengthy breeding cycles to improve rootstock performance to meet challenges associated with pest and disease
pressures as well as limit the impact of climate change on production.
Plant transformation involves the transfer and integration of DNA, including genes, into the genome of a plant cell. Once transformed, a plant must be generated from the transgenic cell(s) (Motte et al. 2014). Therefore, the first step in developing a plant transformation method is to establish a plant regeneration system. When floral organs, leaves and vegetative shoots are removed from a plant and placed in tissue culture on media that induces cell proliferation, dedifferentiated tissue termed ‘callus’ develops at the cut site (Chen et al. 2022). After callus forms, this tissue must be progressed to a state in which plants can be regenerated in an effective manner. At this point, a plant’s regenerative callus cells can be genetically transformed using Agrobacterium tumefaciens. The regeneration of plants from transformed callus cells is
Figure 1. After sterilization, flowers are dissected, and stamens are placed on callus induction media. Callus derived from the cut ends of stamens are placed on media to induce pre-embryogenic callus formation*. After proliferation, embryogenic callus development is induced, which allows for the regeneration of plants. Once the embryogenic regeneration system is established, genes can be transformed into the cells of embryogenic callus for the selection and regeneration of transgenic plants. The transitions from pre-embryogenic callus to plantlet regeneration involve the manipulation of auxin and cytokinin.
achieved by manipulating the levels of auxin and cytokinin, two major hormones that regulate cell division and
differentiation during plant development (Ikeuchi et al. 2016; 2013). Generating genetically transformable callus with the capacity to undergo plant regeneration is the primary objective of the HORT57 project.
and packs it all in one operation. The right equipment does make the difference: better floor preparation leads to better orchard management and trouble-free harvests.
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Regeneration of Prunus rootstocks from somatic or adult tissue has been previously performed from leaves and stems (Gentile et al. 2002; PérezJiménez et al. 2012; Sabbadini et al. 2015). A plant regeneration system termed shoot “meristem bulk” was evaluated for developing transgenic rootstocks (Sabbadini et al. 2015; 2019). Results showed that while GF677 transgenic plants could be produced at a low rate, most of these selected rootstocks were chimeric, a plant comprised of genetically modified and non-transgenic cells (Sabbadini et al., 2015). In addition, shoot meristem bulk callus derived from Hansen 536 was recently transformed (Sabbadini et al. 2019). However, plants could not be regenerated from the transgenic Hansen 536 shoot meristem bulk callus. Therefore, the regeneration and selection of transgenic plants is a major bottleneck in the development of a Prunus rootstock genetic transformation system.
In the HORT57 project, we are developing an embryogenic plant regeneration system for Prunus rootstock
transformation using expertise derived from our grapevine transformation team. To date, we developed an effective method to sterilize floral buds and induce pre-embryogenic callus from the stamens of Hansen 536, Nemaguard, GF677 and Brights Hybrid (data not shown). Currently, we are developing a method to induce embryogenic callus formation, which will be directly used to regenerate plants. If successful, the embryogenic callus regeneration system can be utilized to develop Prunus rootstock transformation system (Figure 1). In addition, we are also evaluating the shoot meristem bulk method to determine if we can increase the plant regeneration efficiency of this system.
The authors would like to thank Almond Board of California for funding the HORT57 project and Mandy Walker for developing the project proposal.
Chen, Z., Debernardi, J.M., Dubcovsky, J., Gallovotti, A. (2022) Recent advances in crop transformation technologies. Nature Plants 8: 1343-1351.
Gentile, A., Monticelli, S., Damiano,
C. (2002) Adventitious shoot regeneration in peach [Prunus persica (L.) Batsch]. Plant Cell Reports 20: 1011-1016.
Ikeuchi, M., Sugimoto, K., Iwase, A. (2013) Plant Callus: Mechanisms of induction and repression. Plant Cell 25: 3159-3173.
Ikeuchi, M., Ogawa, Y., Iwase, A., Sugimoto, K. (2013) Plant regeneration: cellular origins and molecular mechanisms. Development 143: 1442-1451.
Lobell, D.B., Field, C.B. (2011) California perennial crops in a changing climate. Climate Change 109: 317-333.
Luedeling E., Girvetz, E.H., Semenov, M.A., Brown, P.H. (2011) Climate change affects winter chill for temperate fruit and nut trees. PLoS One 6(5): e20155
Motte, H., Vereecke, D., Geelen, D., Werbrouck, S. (2014) The molecular path to in vitro shoot regeneration. Biotechnology Advances 32: 107-121.
Pérez-Jiménez, M., Carrillo-Navarro, A., Cos-Terrer, J. (2012) Regeneration of peach (Prunus persica L. Batsch) cultivars and Prunus persica x Prunus dulcis rootstocks via organogenesis. Plant Cell Tissue Organ Culture 108: 55-62.
Sabbadini, S., Pandolfini, T., Girolomini, L., Molesini, B., Navacchi, O. Peach (Prunus persica L.). In Agrobacterium Protocols; Wang, K., Ed.; Springer: New York, NY USA, 2015; Volume 2, pp. 205-215.
Sabbadini, S., Ricci, A., Limera, C., Baldoni, D., Capriotti, L., Mezzetti, B. (2019) Factors affecting the regeneration, via organogenesis and selection of transgenic calli in peach rootstock Hansen 536 (Prunus persica x Prunus amygdalus) to express an RNAi construct against PPV virus. Plants (Basel) 8:178. Westphal, A., Maung, Z.T., Doll, D.A., Yaghmour, M.A., Chitambar, J.J., Subbotin, S.A. (2019) First report of peach root-knot nematode, Meloidogyne floridensis infecting almond on root knot nematode resistant ‘Hansen 536’, ‘Brights Hybrids 5’ rootstocks in California, USA. Journal of Nematology 51: 1-3.
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Writer
God blessed us with a darn good slug of water in most parts of the state and the Sierra Nevadas are certainly holding an abundance more in snowpack. Shasta and Orville are way above historical averages, and typically, Oroville gets filled with snow melt more than rain fall. Add that up and we may see it full again for only the second time in its history! To kick things off correctly, let’s make a plan.
This will be a tough start to the year for many farm-
ers in the walnut and almond industries. With prices at significant deficits, many farmers chose to abstain from adding soil amendments to their fields this fall. Let’s look at two scenarios:
Scenario #1
You applied compost. Hopefully, you worked it in a couple inches to avoid degradation and volatility. With that application, it provided some nutrients and organic matter (carbon) as well as some active biology. Nice work. If didn’t, you can skip the middlemen right now (time, weather, pH, etc.). Many companies sell active brews of biology that you can run through your drip or sprinklers (full disclosure, the company I work for does too, so I am biased by my experience and observations.) Let’s make it more effective; add organic acids, which is what we hope the compost eventually breaks down to, and keep the biology colonizing and propagating. That’s a lot of extra carbon. The roots will love the that immediate source of carbon. You’ll hold more nutrients that become available or are applied as well.
Scenario #2
You applied gypsum. If you do the math, you applied twice the amount of calcium needed in-season with each ton. The problem is its solubility is lethargic at best. Without active biology, low pH water and weathering, it won’t be available for a while. I’ll use my old analogy of meat: If you are hungry, a cooked steak is better than a frozen side of beef. The second is way more than you can use with no way to eat it. Let’s add to that. If the soil is your refrigerator and you fill it with the side of beef, there isn’t much room for any other food. However, if you did add a ton or two of gypsum, add some active biology to your soil to eat it and break it down. Lower your early water pH to 6 to solubilize more calcium. The roots will love it. If you didn’t apply CaSO4, add some soluble calcium to your early irrigations for root flush at bloom. Couple that with organic acids and biology. Do not apply a year’s
supply of phosphorus (15 to 30 units) as a polyphosphate all at once to a single fertigation unless you are trying to make plaster of Paris. You will tie up several nutrients that are critical early in the season.
More specifically on nutrition, look at your nutrient demand curves for your crop. fruitsandnuts.UCDavis. edu has a lot of resources to help you determine when those nutrients are in high demand. N and P demand start high early in the season. Know how much can be taken up at one time. Just because you put out all that it should need in a season doesn’t mean it’ll be there in the root zone, plant-ready and soluble for several weeks. Don’t apply 50 units at a time, three times for three months and hope it all gets assimilated. Apply 15 units, 7 times over 10-day intervals, in short fertigation sets and let me know how that works out for you! I’ve seen it become a significant savings in nutrient costs and a better way to get nutrients into a tree. Overapplication in single events doesn’t translate into better availability. It typically becomes a wasted pile of money. Imagine applying 100 to 120 units N in a more effective way, saving $100/ac and having those April and July tissue tests be sufficient. It’s been eye-opening for quite a few of my clients. Apply your early P in a few smaller shots as well and make sure its orthophosphate. Add a little phosphite to that if you really want to put your roots on steroids! I’ve found that combo to be very effective at increasing early P numbers.
The third component is water. With saturated soils and good, deep moisture, unless we still have a large leaching fraction to overcome, start with shorter sets more often. It’ll keep the roots less soggy when water typically can’t move out of the root zone as quickly in spring and give you the chance to pulse some effective early nutrition into those crops as they push through bloom and leaf expansion. I’ve found that by tweaking that irrigation schedule a little bit, early in the sea-
son, we can save a significant amount of water, electricity and total nutrient applications. We should then be getting our trees off to a much better start. It also seems to help keep deep moisture from subbing up until quite a bit later in the season.
When prices are down, we have to optimize our yields while typically cutting some costs. It’s obviously much harder to do than can be explained
on paper in less than 1000 words. If we plan ahead and watch every input coupled with a more effective delivery method, we should be able to do just that. Let’s take advantage of this gift of water and use it to our advantage in planning to succeed. Higher yields can help lessen the hit of lower prices.
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The New Year has ushered in torrential, sustained precipitation for northern and central California. Managing such a large influx of water in a short amount of time has tested California’s infrastructure, municipalities and landowners.
Despite the challenges brought by the current situation, a unique opportunity presents itself for buffering against ongoing and future droughts: Capturing excess flood flows to recharge critically overdrafted groundwater basins. This timely topic, along with updates related to the Sustainable Groundwater Management Act (SGMA) and acute water shortages, were thoroughly discussed by a panel of experts at last month’s 50th Annual Almond Conference.
“It’s difficult to talk about groundwater recharge in a drought year and when you don’t have enough water to irrigate your farms,” said Daniel Mountjoy, director of resource
stewardship at Sustainable Conservation. “But we know this is coming. We will see another wet year. If you recall the last wet years of 2017 and 2019, most of us were talking about how much water was being wasted and going down the river to the ocean. The only way to not say that again the next time we have a wet year is to be prepared, and that means getting ready now in the dry years to figure out how you’re going to capture water.”
To help individual growers prepare for recharge, the Almond Board of California (ABC), in partnership with Sustainable Conservation, recently published a guide titled, “Introduction to Groundwater Recharge.” The easy-to-read resource helps almond growers evaluate their options for conducting groundwater recharge by describing factors to consider and
primary recharge methods available, such as:
• Do I have access to surface water for recharge? Growers need to work with local Groundwater Sustainability Agencies (GSAs) and irrigation districts to determine available surface water supplies.
• Is my orchard soil suitable for recharge? Sandy soils are preferred for on-farm recharge as these types of soils rarely become saturated and are less likely to cause harm to crops. UC Davis developed the Soil Agricultural Groundwater Banking Index (casoilresource.lawr.ucdavis. edu/sagbi/) to determine suitability for groundwater recharge on agricultural land. ABC, in partnership with Land IQ, developed an online tool that provides an initial look at site recharge suitability for on-farm recharge.
• What recharge methods are available? Surface applications to orchards, basin and water conveyance structures, and below-the-surface methods are discussed in the guide.
• What orchard management changes are necessary to perform recharge? Consideration of irrigation set-up, field berms and infiltration practices are discussed in the guide.
On-farm recharge offers an attractive, cost-effective method for replenishing underground aquifers, Mountjoy noted.
“The most economical way to store water in the state right now is putting water back on the ground and into the aquifer,” he said. “It’s cheaper than districts buying land and building basins; it’s cheaper than building new reservoirs; it’s cheaper than more canals.” However, on-farm recharge is not as simple as a grower deciding to just do it. Timely capture and movement of
surface water for on-farm recharge is largely out of a grower’s hand, requiring action and coordination among several stakeholders off the farm, including irrigation districts, flood managers, GSAs and policymakers.
Sustainable Conservation, along with five GSAs, developed the Groundwater Recharge Assessment Tool (GRAT) to identify and prioritize potential groundwater replenishment options for achieving sustainable groundwater supplies. By combining several factors, such as geology, soil type, crop type, crop timing, costs and delivery systems of water districts, GRAT helps stakeholders assess where, when and how much water can be captured under future water availability scenarios.
“This allows scenario planning to figure out if you divert more water at certain times of year, where can you place it based on the cropping system and agronomic conditions and what will be the cost of alternative solutions,” Mountjoy said.
Using GRAT and other tools that considered the effects of climate change, Sustainable Conservation worked with the California Department of Water Resources on a flood-managed aquifer recharge scenario in the Merced Subbasin. Considering the existing farms with crops and soils compatible with groundwater recharge located in the subbasin, the projected offset of annual groundwater oraft ranges from good to better to best across a variety of scenarios:
• Use of existing conveyance infrastructure and on-farm recharge: 31% of average annual overdraft is recharged;
• Reservoir reoperation (where water is released before storms and captured for recharge) and use of existing conveyance infrastructure and on-farm recharge: 46% of average annual overdraft is recharged;
• Expanded conveyance capacity to floodplain areas that are prone to flooding and reservoir reoperation and on-farm recharge: 63% of average annual overdraft is recharged.
Another benefit to these types of smarter water management decisions is the potential to reduce the impacts of more frequent flood events in the future.
“With the increased storm events that we’re starting to see already, we’re going to see a six-fold increase in flood peaks on the Merced River over the next 30 to 40 years,” Mountjoy said. “With this approach, we can release some of that water, capture it and reduce the flood risk by 65% of what is anticipated.”
Given the current weather conditions, the opportunity for groundwater recharge seems ripe and prudent. For growers with favorable farm conditions and access to water for recharge, more incentive funding programs are becoming available, such as the pilot NRCS groundwater recharge program, grants for land repurposing and local GSA programs.
If your farm isn’t suitable for recharge, that doesn’t mean you can’t
participate in advancing the practice of groundwater recharge, Mountjoy noted. “You should be the one advocating for these regional solutions that benefit us all or supporting policies that allow more water to be diverted at the right
time to protect aquatic systems and capture and reduce flood risks.”
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ACalifornia Pistachio Research Board-funded tree training and staking trial looks to bring pistachio trees into production more rapidly, at a lower cost while improving water use efficiency and establishing a strong tree structure.
Led by UC Davis Plant Biologist Bruce Lampinen, this trial compared conventional pistachio tree training from the Pistachio Production Manual with wooden stakes, a modified central leader on 5/16 inches by eight feet with metal stakes and untrained 3/8 inches by 10 feet with metal stakes.
The trial consisted of two sites in
Kings County, one in Yolo County and another at the Westside Research Station planted in 2019. The first Kings County site was initiated in a Lost Hills on PG1 seedling rootstock with double line drip irrigation. The second Kings
24 inches were tipped. In addition, the most central shoot was tipped and retrained to a central leader and left longer than all other shoots.
The untrained trial at 3/8 inches by 10 feet and metal stakes had no heading
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the ties release themselves. Photosynthetically active radiation interception (PAR) was measured each year with a mobile platform lightbar.
At the Kings County trial site, first harvest was done at fourth leaf in 2019. The untrained trees yielded 55 pounds per acre, while harvest was negligible for conventional and modified central leader trained trees. At fifth leaf, the untrained trees outproduced at 1,905
pounds per acre while conventional trees produced 535 pounds per acre and central leader trees produced 951 pounds per acre. This trend continued, but by seventh leaf harvest, the modified central leader trees had nearly caught up to the untrained trees in production at 5,288 pounds and 5,703 pounds per acre, respectively. The conventionally trained trees lagged at 3,985 pounds per acre. The yield per unit of PAR intercepted followed the same pattern with untrained trees leading the way. The percent removal on the
first shake in 2022 was not significantly different, Lampinen said.
A second trial site in Kings County showed the untrained trees yielding the first harvest at fourth leaf. At fifth leaf, untrained trees continued to out yield, but both other treatments were closing in. By sixth leaf, the untrained trees yielded 3,241 pounds per acre, the modified central leader trees topped the production at 3,302 pounds per acre and the conventional trees came in close third at 2,954 pounds per acre. Percent removal in the 2022 harvest was nearly identical.
The Yolo County trial, planted February 18, 2018, had Golden Hills on UCB1 seedling. The trees were nursery grafted, and Lampinen noted that frost damage in the nursery resulted in about 50% of terminal shoots being damaged. For the untrained trees, 2022 and 2020 were years with no neoformed growth. This year, there should be more, Lampinen said.
Labor costs for pruning were also counted. Over four years, for conventional trees, there were 7,518 cuts per acre, or 601,440 cuts on 80 acres. Pruning cut numbers for conventional and modified central leader trees were nearly the same.
Lampinen said the Yolo County trial site trees were growing more
vigorouslyThe trials hold promise for labor savings over conventional pruning practices.
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than either of the Kings County sites. At the Yolo site, cuts per 80 acres for the first four years was at 601,440 for the conventionally pruned trees and 595,200 for the modified central leader trees.
At third leaf, 15% of unpruned trees at the Kings County site #1 required ties. At the Kings County site #2, 42% of the unpruned trees needed ties, while at the Yolo County site, 10% of unpruned trees needed ties.
The Yolo County site was hand-harvested in 2021 at fourth leaf and untrained trees had a cumulative yield of 156 pounds per acre, compared to 17 pounds per acre for conventional and 45 pounds per acre for modified central leader. A mechanical harvest the following year repeated the trend with unpruned trees, yielding 504 pounds per acre, while conventional trees yielded 54 pounds per acre and modified central leader trees yielded 144 pounds per acre.
Data from the processor showed nearly identical edible yield, but untrained trees had a higher percentage of shelling stock and a much lower percentage of blanks. Conventionally pruned trees had the highest percentage of closed shell and the highest percentage of blanks but was followed closely by the modified central leader.
The secondary staking trial at the Yolo site and the Kings County site #1 showed that wooden stakes tended to lead to smaller rootstock diameter compared to metal stakes. Lampinen also noted that leaving rootstock sprouts on tended to result in larger rootstocks and smaller scions.
Measurement of rootstock and scion circumference at the Westside site showed Golden Hills larger than Kerman and Platinum-rooted trees larger than UCB1 seedling. The first harvest of those trees is anticipated this year.
Lampinen noted that conventionally pruned trees have large shoots that grew in response to dormant heading cuts the previous winter. Unpruned trees have shoots that have multiple ages on a given shoot. The two-year-old shoot has developed a complexity that is lagging one year behind on the con-
ventionally pruned trees. He said that most limb breakage that occurred following harvest in 2018 was at the point where the initial in-season tipping cut occurred the second year. This is likely, he added, because the two buds that pushed out in response to the tipping were very close together and ended up with included bark. Limb connections, Lampinen said, are very strong in modified central leader and untrained trees.
Summarizing progress at all trial sites, Lampinen said that modified
central leader and untrained trees had larger rootstocks, stronger branch connections, taller trees, more early fruiting positions, earlier yield potential and higher water use efficiency. Untrained trees also had much lower labor costs.
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As we have reported in this column several times over the past year, pesticide activists are going all out against pesticide use in California and using every mechanism they can to attempt to accomplish that goal. The latest attack comes from the Center for Biological Diversity (CBD) and Californians for Pesticide Reform (CPR) who submitted a petition to request that the California Air Resources Board (CARB) initiate a rulemaking and other appropriate actions to add sulfuryl fluoride to its greenhouse gas inventory and phase out the use of sulfuryl fluoride in California. Sulfuryl fluoride is used in residential fumigation where it is known as Vikane and in commodity fumigation as Profume.
According to CBD, “This action is necessary due to sulfuryl fluoride’s high Global Warming Potential (GWP). Sulfuryl fluoride is 4,800 times more potent than carbon dioxide in trapping heat, consequently contributing to climate change, and it is a threat to public health. Sulfuryl fluoride also lasts in the atmosphere for 36 years, eight times longer than the lifespan previously assumed when CARB last considered the regulation of sulfuryl fluoride as a greenhouse gas. The concentration of sulfuryl fluoride in the atmosphere is drastically increasing despite the development of successful alternatives to treat insect infestations. California is the
largest consumer of sulfuryl fluoride in the world, consuming approximately three million pounds in 2021. Sulfuryl fluoride is also a recognized toxic air contaminant and a neurotoxin, which causes illness, disabilities and death. At least 16 deaths have been attributed to sulfuryl fluoride use in California. The time has come for CARB, an agency committed to climate leadership and public health, to regulate sulfuryl fluo ride and phase out its use.”
The largest use of sulfuryl fluoride is in residential use, so most of the petitioners’ comments are focused on residential use. Interestingly, the petitioners claim there are “viable alter natives” to the use of sulfuryl fluoride. These alternatives include temperature manipulation for whole structure treatment, numerous localized treat ment options and prevention methods established through Integrated Pest Management. The petitioners claim the
heat treatment is the ability to treat theof time the structure must be vacated (typically a few hours compared to the Orange oil is an alternative treatment extracted from orange peels. The major
‘The petitioners don’t consider any benefits from the use of sulfuryl fluoride, which is now widely used in tree nut fumigation to replace methyl bromide and phosphine, fumigants also targeted by anti-pesticide activists.’
called terpenes or terpenoids and the major active ingredient is d-limonene. D-limonene is considered safe and has a low toxicity. In a 2020 study, orange oil coupled with heat treatment and d-limonene vapors resulted in either complete or almost complete mortality after several days of exposure, including in what would be a heat sink area.
Microwaves
Microwave devices are also available for termite control. Microwaves kill termites by causing fluids inside their cells to boil, which destroys cell membranes.
Electrocution
High-voltage electricity, or electrocution, is another nonchemical option. The device used emits high voltage (90,000 volts) but has a low current (less than 0.5 amps). Death to drywood termites occurs by electric shock, although delayed mortality may also occur from the destruction of intestinal protozoa.
Baiting
Research is currently underway under California’s DPR Pest Management Grant to explore the concept of an “in-wood” baiting system for drywood termites using chitin biosynthesis inhibitors, which are synthetic hormones, as active ingredients. With the bait, the affected termites return to the central part of the colony and die in the vicinity of reproductive termites and eggs. Whether these controls work or not or are even applicable to commodity fumigation use of sulfuryl fluoride, it is necessary to step back and determine if it is even necessary to consider a ban on the use of sulfuryl fluoride. When you consider the amount of sulfuryl fluoride used, it is negligible in terms of its contribution to climate change. The total annual emissions of sulfuryl fluoride from all sources only amounts to 0.035% of the current total manmade greenhouse gas emissions. To put that in perspective, the concentrations of sulfuryl fluoride in the atmosphere are roughly analogous to a distance of 0.9 miles traveled by a single car compared to the total vehicle miles traveled (VMT) per year by all of the
vehicles in California (about 340 billion VMT), or half a single grape compared to the total annual grape production in California (about 5.6 million tons.) Ridiculous!
The petitioners don’t consider any benefits from the use of sulfuryl fluoride, which is now widely used in tree nut fumigation to replace methyl bromide and phosphine, fumigants also targeted by anti-pesticide activists. Sulfuryl fluoride is considered a much safer and more effective alternative
and will become a huge issue should CARB consider any action here. The agricultural industry and, in particular, our organization, are actively working against this petition and respectfully requesting CARB to use common sense and practicality when addressing the activists’ complaints and accusations.
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The renovation of two research laboratories and construction of three new labs at North Willamette Research and Extension Center (NWREC) in Aurora, Ore. is expected to enhance research capabilities for Nik Wiman, Oregon State University Extension orchard specialist, particularly when it comes to insect management in hazelnuts.
“That will give him more space to accommodate insect rearing and other research activities,” said Surendra Dara, director of the station. “Nik’s current space is very tiny.”
The new labs, one dedicated to soils and chemistry and one to plants and a molecular lab, are housed at the Parker House, a farmhouse adjacent to the main office at NWREC. The labs were inaugurated in December and were expected to open in January or February.
Construction crews were expected to start renovating the station’s old labs, which are located in the basement of the main building, after researchers moved into the new labs. Once the ren-
ovation is complete, Wiman will have space in both sets of the shared labs.
The construction of the new labs was made possible by a donation of $250,000 from Northwest Farm Credit Services and from $425,000 of capital improvement funds provided by the university’s College of Agricultural Sciences.
The renovation of the old lab is being funded by a $500,000 donation from local farmers Carl and Kim Casale. Carl Casale, a former president and CEO of CHS, currently serves as a senior partner at Ospraie Management
LLC, a New York investment firm. The Casales own and manage a family farm near the Aurora station.
The Casale donation was the largest ever private donation for the station, according to former station director Mike Bondi, who retired in 2021.
Developments to improve the station’s facilities were jumpstarted when Bondi submitted a proposal to the OSU College of Agricultural Sciences to utilize a state fund dedicated to capital
We had never seen this kind of funding in the past, and it has been really appreciated with so many of our off-campus facilities needing updating.
– Mike Bondi, Oregon State University Emeritus
improvements at off-campus facilities that was created in 2019. The initial capital improvement funding, which came later that year, supported two projects: a new well for the farm and the Parker Lab construction.
“The Parker Lab project received the maximum award from the college [for that funding source] of $425,000,” Bondi said.
Bondi added that the funding source was created by the 2019 Oregon Legislature, which dedicated about $2 million in state funding each biennium for 10 years specifically for improvements at off-campus facilities.
“We had never seen this kind of funding in the past, and it has been really appreciated with so many of our off-campus facilities needing updating,” Bondi said.
Still, the project budget for Parker House exceeded the College of Agricultural Sciences funding, Bondi said. Northwest Farm Credit Services came up with the additional funds.
“The College of Agricultural Sciences has been supported by Northwest Farm Credit Services for years, where they pick several programs to direct their funding,” Bondi said. “I believe our Northwest Farm Credit Services Advisory Coun-
cil members, who were knowledgeable about our lab remodel project and knew we needed additional funding to complete it the way we wanted and needed to, put in a good word for us with NWFCS as they prioritized their $1.5 million gift in 2020.”
In the latter part of 2020, Bondi then met with Carl and Kim Casale, who, according to Bondi, were looking for projects to support with their personal philanthropy.
“I met with them and toured our facilities and shared the big plans to remodel Parker,” Bondi said. “Planning was well underway, and the initial demo was in process. Carl and Kim saw a lot going on, other commitments being made, upgrades and improvements already in motion and decided their funding could continue to build on our momentum.”
Their funding was committed in spring 2021, Bondi said.
“This has been a nice addition,” Dara said. “Space is the big need for everybody here, whether it is office space, lab or greenhouse space, and these funds and donations are really helping us to get these needs addressed.”
NWREC, a 160-acre facility located about 25 miles south of Portland, is OSU’s only agriculture field research station in the Northwest part of the state. It serves farmers in a seven-county area focusing on cropping systems common in the Willamette Valley, including nursery crops, fresh vegetables, specialty seed crops, berries and orchard crops including hazelnuts.
NWREC also is the location of the state’s only IR-4 Pesticide Registration program, which works to obtain pesticide registration for minor crops including hazelnuts.
Wiman has planted a six-acre hazelnut orchard with the varieties Jefferson, McDonald, Yamhill and Wepster.
Among other projects, Wiman is working on horticultural practices, irrigation and nutrient management as well as
control tactics for diseases and insects.
One of seven faculty members leading researcher programs at the site, Wiman has two assistants, a graduate student and multiple undergraduate assistants working under him.
He, along with seven other OSU researchers, published a paper online this past fall outlining the economic impacts of hazelnut pests and their management, a report that showed a 43% difference between the maximum attainable yield and the actual yield of hazelnuts. About half of the difference was attributed to pest damage, according to the report. The findings were based on responses to a survey distributed to hazelnut producers.
The survey is helping researchers determine priorities, according to the report, and, according to Dara, highlights the need for continuing hazelnut research.
Respondents reported diseases as having the largest negative impact on hazelnut yield at around 6.1% of yield loss per acre. Invertebrates were the next largest negative impact with an estimated 5.8% yield loss effect per acre.
Eastern filbert blight, aphids and filbertworm were the dominate species causing negative yield impacts, according to the report. Those three accounted for close to 10% yield loss on average.
Since the survey, brown mar-
morated stink bug has emerged as a significant pest in hazelnuts as well, and Wiman is working to help growers control it through chemical and non-chemical approaches, including use of an egg parasite, Trissolcus japonicus, known commonly as the samurai wasp.
Native to China, Japan and Korea, which is the same native range of the brown marmorated stink bug, the samurai wasp was accidentally introduced in the western U.S. and first recorded in Vancouver, Wash. in 2015.
The wasp parasitizes the eggs of brown marmorated stink bug, and adult wasps emerge from eggs by chewing their way out.
Wiman has asked growers to inform researchers if they see evidence of parasitized egg masses. Go to agsci.oregonstate.edu/bmsb for information on how to report a finding.
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Sensors installed in tree trunks or scaffold branches measure plant moisture status automatically, enabling users to fine-tune their irrigation while reducing the need to take time-consuming pressure bomb readings.
At least three manufacturers market tree sensors: Davis-based FloraPulse, Rancho Cordova-based Saturas USA and Tulare-based Phytech US. Each uses a different technology to reach the same goal: automating the labor-intensive practice of measuring tree water stress.
FloraPulse uses microtensiometers to provide stem water potential readings every 20 minutes. Saturas uses osometers to measure stem water potential (SWP) and provides a daily report. Phytech uses dendrometers to measure trunk expansion and contraction. This is translated into a tree stress index ranging from 0 to 100 (what it calls MDS or Maximum Daily Shrinkage.)
Although the technology isn’t cheap, proponents say it may pay for itself with potential water savings, labor savings, yield and quality improvements, and healthier trees.
“We have seen growers who have definitely saved water,” said Michael Santiago, CEO and a founder of FloraPulse. “One of our growers was able to reduce water use by almost 50%, but that may not be typical. If they’re doing pressure bombing, they can save on that. And depending on the soil, people may not be irrigating frequently enough. It’s hard to describe the individual benefits, but it definitely helps them irrigate better.”
Ziv Atia, head of agronomy for Phytech, agreed and said that as with every new technology, grower adoption is gradual. Phytech has onsite teams that help growers through the implementation process by pinpointing real time opportunities to increase return on investment and improve grower success.
“The benefits of using the Phytech system is grower specific and depends on predetermined goals set in the beginning of the season like increase in yield quality and quantity, decrease in amounts of water applied and
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energy consumption, and improved water/fertilizer use efficiency and increased operational visibility,” he said.
Nut growers traditionally rely on ETc calculations, historic irrigation data or soil moisture measurements to determine specific parameters such as filled capacity, permanent wilting point and maximum allowable depletion in order to get a recommend amount of applied water. But Phytech uses multiple sensors, which monitor the plant’s real-time physiological state based on MDS and growth rates to determine best irrigation practices. Atia said growers therefore get a more complete picture for planning irrigation schedules and evaluating the effectiveness of a certain irrigation protocol.
Atia said Phytech’s plant status
calculations provide a continual measurement of stress and installing one dendrometer a tree trunk per plot enables daily granular plot monitoring in complete ranches, which would require a “small army” using traditional manual pressure chambers.
Phytech currently services about 167,000 acres of almonds, pistachios and walnuts in California and acreage continues to grow, Atia said.
Ryan Kaplan of Pressure Bomb Express, also a FloraPulse dealer in Northern California, said he had more than 50 units in mostly almond growers’ orchards last year, and he would have had more were it not for supply chain issues that limited availability of some of the components. Kaplan said he sees increasing interest in the
technology because of its labor savings, frequent SWP readings and water savings potential.
“I haven’t done sales yet this year, but I do know that all of the growers who used it last season want to continue,” he said. “With commodity prices being down and input costs up, I’m not sure how many growers are going to want to spend on new technology. But this is technology that could significantly increase their bottom line as well as overall orchard health.”
As with any new technology, Kaplan said the FloraPulse sensors are not 100%, but they’re “super promising” and issues are infrequent. He recommended pairing them with midday SWP readings from pressure bombs, long considered the gold standard, at least until users understand how readings from the two technologies correlate.
“It’s not going to be perfect, but it’s going to be pretty close,” said Kaplan, a second-generation grower who uses FloraPulse sensors in his own prune and pistachio orchards near Orland. “If you have pressure bomb readings, you can compare them. If it’s consistently off by the same amount, then we can calibrate [the sensor]. At this point, I think growers need to own a pressure bomb and take readings on the sensor tree or you can work with a company to take a couple of comparison readings on the tree.”
FloraPulse, founded by three Cornell University researchers, offers the technology through an annual subscription and recommends one unit per irrigation block. Within nut crops, the sensors have performed well in almonds and pistachios, but Santiago said they’re still having some challenges with walnuts and pecans.
During sensor installation, a small wound is made in the tree trunk or scaffold. Walnuts and pecans have a strong wound response, which overwhelms the sensor and prevents it from accurately reading water status within the xylem.
“We’re working on ways around that and we’ve had some success, but things like this take time,” he said. “We’re developing a new installation method
with Dr. Shackel.”
Although soil moisture sensors can provide information about the amount of moisture in the soil, they don’t reflect how much of that is actually being taken up by the tree. Stem water potential gives a reading of what’s occurring within the xylem (tissue that transports water from plant roots to stems and leaves.)
Water in the xylem is always under some degree of tension. As evapotranspiration increases, the roots can’t keep pace and the tension increases. Reported as a negative value or as negative bars, the tension is an indication of a water deficit or water stress.
During the middle of the day when temperatures near their peak and photosynthesis is greatest, the tree is most actively pulling moisture through the xylem into the leaves. This timing typically coincides with the tree’s greatest water stress and recommended midday
ContinuedonPage54
SWP pressure bomb or pressure chamber readings.
In a two-year almond trial at the Kearney Agricultural Research and Extension Center near Parlier, Calif., Ken Shackel, UC Davis professor of plant science and pomology, compared pressure bomb midday SWP readings to those from the three sensors. Overall, he found seasonal stress patterns were similar with all sensors with varying levels of correlation to traditional pressure bomb readings.
Ideally, Kaplan said FloraPulse sensors should be installed during cold mornings shortly after leaf-out. The process begins with selecting a healthy tree that’s representative of the block.
Placing the sensor in a 2-inch scaffold branch or high on the main trunk helps avoid possible shaker damage.
Installation is relatively straight forward and takes 40 to 45 minutes. But Kaplan said some grower-customers are initially hesitant about doing it themselves, so he shows them how to do it so they can do so in the future if they choose.
Users hammer a metal sleeve about the diameter of the pinky finger into the tree until it hits the hardwood core. After drilling out the debris in the sleeve, users fill it with a special “mating” or bonding compound before pushing the sensor into the sleeve. They cap the sensor and apply grease around the sleeve hole. To provide redundancy, a second sensor is installed nearby but at least 3 inches diagonally or to the side. The sensors are then wrapped with reflective insulation, which is zip-tied in place. A pressure switch also is connected to the drip irrigation hose so users can see whether water is running.
roughly 4-by-8-inch box, in a tree crotch where it won’t be
easily dislodged and zip-tie it and the wires leading from the sensors in place.
The datalogger, powered by a small solar panel, searches for the best cell signal to use to send data. At times, finding a cell signal can be a challenge, and Kaplan said there are some orchards where data transmission isn’t feasible.
Currently, FloraPulse sensors maintain accuracy for one season and new ones have to be installed before the beginning of the following season. Santiago said it may be that the tree is trying to wall off the wound as a defense mechanism. But making sensors that last more than a season is one of their many goals.
For the Phytech system, dendrometers are installed above the graft line using a single screw year-round, however, ideally for mature bearing trees, Atia recommends installation at the beginning of the season prior to leaf out and bloom to allow tree monitoring throughout all the different phenological stages.
“By doing so we promote growth and decrease stress level during key phenological stages, and increase water/nutrient use efficiency, hence, the grower’s chances to meet the orchard yield potential,“ Atia said
In young nonbearing trees he recommends monitoring when trunk diameter is around 1 inch. Preventing stress and promoting maximum growth rates in young trees will allow faster orchard establishment and decrease time until the orchard will reach full production potential. The dendrometers are part of a full suite of Phytech farm management technology.
Environmental conditions, such as temperature and relative humidity, affect what normal or “baseline” pressure bomb midday SWP values should be in a fully irrigated
orchard. This also should hold true for FloraPulse sensor midday readings, since they generally are similar to those of pressure bombs.
University of California has tables for download at bit.ly/3b1C9KF that calculate baselines based on temperature and humidity. A website is also available (informatics.plantsciences. ucdavis.edu/Brooke_Jacobs/index.php) that provides these values for the last six days for any of the CIMIS weather station locations.
The tree growth stage during the season also influences the amount of stress desired. In almonds, for example, moderate stress shortly before hull split reduces hull rot and stick-tights and promotes more even nut removal.
By comparing baseline values to actual midday SWP measurements in their orchard, users can determine whether irrigation is needed.
To streamline those calculations, Kaplan developed the Pressure Bomb
Express app, which runs on a smartphone or tablet. Although initially designed for use with pressure bombs, he said the latest versions also accept data downloaded automatically from FloraPulse sensors.
“Because we’re measuring the same thing with the manual pressure bomb and the sensors, we can download the data into the app and review it and display it the same as manual samples,” he said.
Drawing from years of UC pressure chamber research, the app builds a report showing the level of tree stress and recommendations with the baseline and crop-specific seasonal growth stages already factored in. It also allows users to compare manual pressure bomb readings to those of the FloraPulse sensors all on one screen.
Pressure Bomb Express for manual pressure bomb use is available through a subscription, which includes updates and training. When FloraPulse sensors
are purchased through Pressure Bomb Express, growers also gain access to their sensor data on the Pressure Bomb Express app at no additional cost.
Phytech uses an IoT platform, and all sensors are wireless. Data from each individual sensor is sent to central data loggers that distributed evenly throughout the plots. Data loggers transmit the data to via cellular network to a cloud-based server where further analysis is done. Phytech uses crop / verity specific algorithms to determine the plant status (a plant health index based on water availability) and deliver an intuitive color-coded indicator of that PS through am app or web site. A dedicated team of will follow up through the entire season to help increase embedding the technology for optimum results.
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By CALIFORNIA WALNUT BOARD | Contributing Writer
Through nearly two decades of supporting walnut nutrition research, California Walnut Commission (CWC) has helped reposition walnuts in consumers’ minds as a goodfor-you food and has made walnuts known across the globe for their many health benefits, which hasn’t always been the case. Walnuts once had low visibility as a healthful option, which CWC set out to change through support of scientific research on how the consumption of
walnuts affects human health. This research has uncovered many important and exciting findings about the effects of walnut consumption on heart health, cognition, cancer, diabetes, metabolic syndrome, gut health, body weight/composition, reproductive health and more. As research deepened walnuts’ association with nutrition and consumer health, in late 2022, the FDA released an updated proposed definition of the term “healthy,” with walnuts
meeting the proposed definition for the first time.
As Health Research Director for CWC, Carol Sloan, R.D. played a key role in advancing health research on behalf of walnuts. Since her work at CWC began in 2000, Sloan not only helped implement and oversee active research studies internationally and domestically, she synthesized the scientific data for marketing programs and global consumer audiences, highlighted data findings for key stakeholders and health professionals, and relayed findings to the key personnel who influence public policy. Research showing the many benefits of walnuts has been beneficial in supporting recommendations for walnut consumption in the U.S. Dietary Guidelines for Americans as well as providing evidence for including walnuts in the new FDA proposed definition of
In late 2022, Sloan capped her tenure
with CWC by announcing her retirement.
“When people think of walnuts today, they think of a healthy nut and omega-3 ALA, but that hasn’t always been the case. The nutrition research that Carol has heralded over the last two decades has been a valuable tool in getting walnuts in more homes around the world,” said Robert Verloop, president of CWC. “Published research that shows the multitude of walnuts’ health benefits gives CWC the proof points to show that
Nutrients, found that adding one ounce of walnuts (or one handful) to the diet of children and adults who do not normally eat nuts improved the overall diet quality and intake of under-consumed nutrients of public health importance like fiber, potassium and magnesium. These new findings carry forward previous results that suggest walnuts may act as a bridge to better wellbeing.2
A study from researchers from the University of Minnesota School of Public Health found that walnuts act like a bridge to other positive impacts on health, including better-quality diet, being more physically active and having a better heart disease risk profile. The study, published in Nutrition, Metabolism &
Cardiovascular Diseases, looked at 20 years of diet history and 30 years of clinical and physical measurements and suggests reinforcing heart-healthy habits is as simple as…a handful of walnuts!3
References
Herselman MF, et al. The effects of walnuts and academic stress on mental
health, general well-being and the gut microbiota in a sample of university students: A randomised clinical trial. Nutrients. 2022;14:4776.
Yi SY, et al. Association of nut consumption with CVD risk factors in young to middle-aged adults: The Coronary Artery Risk Development in Young Adults (CARDIA) study. Nutrition, Metabolism and Cardiovascular Diseases. 2022;32(10):2321-2329.
all the research projects! However, one project that’s been particularly exciting for me to watch is the male reproductive research with Dr. Wendie Robbins at UCLA. The overall goal of this project was to determine if dietary intake of walnuts would benefit male reproductive health…. and indeed it did! Infertility affects men and women equally, and the fact that health studies have provided encouraging results regarding the role of walnuts in reproductive health is exciting.
Spence LA, Henschel B, Li R, Tekwe CD, Thiagarajah K. Adding walnuts to the usual diet can improve diet quality in the United States: Diet modeling study based on NHANES 2015–2018. Nutrients. 2023; 15(2):258.
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Q What research on walnuts has been most pivotal for advancing nutrition science?
As the California Walnut Commission toasts Carol’s retirement, we connected with her to reflect on her passion for research, walnuts and her leadership in tapping health research to advance the industry.
Q How did your partnership with California Walnuts start?
I first came on board to support CWC at a conference for health professionals in 2000. From that small job, I continued as the Nutrition Consultant for California Walnuts for the next seven years or so working with the marketing team and supported researchers. As the health research program grew, I took on more responsibilities, managing research projects and building visibility for the health benefits of walnuts among health professionals and researchers. In 2016, I was given the title of Health Research Director.
Q Tell us about a walnut nutrition research project of which you are most proud?
Like a mom, there is no favorite child, and the same is to be said of
Also, our research funding collaborations with the American Heart Association and the USDA-National Institute of Food and Agriculture, Agriculture and Food Research Initiative (AFRI) Program have been wonderful. To have third-party organizations want to co-fund new research is a testament to the vision of our members and staff.
Q Over the years, have there been any research projects or results that have surprised you?
A highlight of my time with CWC was working with Dr. Elaine Hardman, who conducted animal model studies and found that mice consuming walnuts had a reduced risk of breast cancer. California Walnuts supported a pilot study she conducted with women who had breast lumps large enough for research and pathology biopsies. Some of these women consumed 2 ounces of walnuts daily for about two weeks. It was found that these subjects had beneficial changes in gene expression, which could suppress growth and survival of breast cancers. It’s remarkable research showing the simple task of consuming walnuts as part of a healthy diet may have such a large impact.
As a registered dietitian for more than 40 years, I have seen significant changes in dietary fat recommendations. When I started my career as an R.D., we were taught to counsel avoidance of all fatty foods and promote consumption of simple carbohydrates. This was based on the research available at the time. Research by Joan Sabaté, M.D., D.Ph., Emilio Ros, M.D., Penny Kris-Etherton, Ph.D., RDN, David Jacobs, Ph.D., David Baer, Ph.D., Linda Tapsell, Ph.D., and so many others changed the way health professionals and consumers looked at and differentiated the types of fat (saturated, monounsaturated, polyunsaturated.) The walnut industry was visionary in supporting dietary fat research as related to walnuts, which are a significant source of plant-based omega-3 ALA (alpha-linolenic acid, 2.5 g/oz).
Q What would you like to share about the future of walnuts as it relates to nutrition?
California Walnuts have a unique nutrient composition, which lends so well to health research. I’m deeply proud of our industry for its commitment to research and the studies conducted to date, especially since research on whole foods is uncommon. Our industry was ahead of the curve when strategically planning support of nutrition and health research, and we have gladly marketed all of the health benefits our research has established. But we’ve just scratched the surface; there is much more to learn about walnut consumption and health!
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At petal fall and rapid leaf expansion there are two core factors affecting yield:
1. The capacity of nut and leaf cells to continue dividing before cell expansion starts, and
2. The ability and efficiency of leaves to photosynthetically produce and rapidly export sugars and proteins to developing nuts.
Nutritionally supporting these two aspects is critical to achieving top yields and quality at harvest. However, soil nutrient availability, root uptake, and nutrient translocation are hindered by the cold and sometimes wet soil conditions of early spring. Under these conditions, the capacity of the plant to naturally source and deliver adequate nutrition falls short of the levels demanded by the flowers and young leaves. The cascading effects of these nutritional deficiencies negatively impact yield by shortening bloom receptivity, reducing nut set, restricting maximum nut size, and decreasing nut retention. In the end, fewer and smaller nuts predominate harvest, shrinking yields.
Foliar nutrient applications bypass these early season limitations and provide unrivaled nutrient delivery to the flowers, developing nuts, and young leaves. To drive the plant beyond these limitations and restore yields, the Right Nutrients must be available at the Right Time, in the Right Form, in the Right Place in the Plant and without undue influence from other nutrients ( Right Mix).
Calcium and zinc are the cornerstones of leaf, nut, root, and vascular development, size potential, and tissue strength. Physiological defects (small leaves, short shoots, and low yields) due to calcium and zinc deficiencies are irreversible and require proper management prior to and at the time of demand. Iron, magnesium, copper, and manganese are vital to chlorophyll production and photosynthetic function (yield). Understanding, planning for, and satisfying these peak nutrient demands not only maximizes yield potential but also saves money by taking advantage of nutrient synergies and avoiding antagonisms.
Applying Sysstem LeafMax, Vigor SeaCal, and Agro-Best 9-24-3 at rapid leaf-out is an ideal way to meet early season almond nutrient needs while simultaneously reducing plant stress.
Cell division in developing leaves and nuts directly impacts yield potential. At petal fall, nut and leaf cell division is not yet finished and foliar applications of calcium, zinc, phosphorus, and seaweed work together to maximize leaf and nut size. An application of Sysstem LeafMax, Vigor SeaCal, and Agro-Best 9-24-3 during petal fall delivers the calcium, zinc, phosphorus, and seaweed needed for heavy yield potential. The micronutrients in the application ensure the photosynthetic factory is able to support a large nut crop while driving nitrogen metabolism in the plant.
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Increasing irrigation efficiency has been an ongoing endeavor in the almond industry, but, as drought and water use pressures on growers increase, more attention is being paid to the technologies designed to further improve
efficiency.
The 50th Almond Conference brought together panelists from the field and the laboratory to explain how sensing technologies and irrigation evaluations can save water and irriga-
tion costs.
An additional conference panel discussion focused on fertigation, making practical recommendations to address increasing nutrient costs and assist with fertilization plans.
Remote sensing tools will be one avenue for managing water and protecting tree health.
“You want to be able to see early stress,” UC Davis researcher Mallika Nocco said. Thermal cameras can capture that early stress. When leaf stomata close in response to high temperatures, leaf temperatures rise.
“A cooler tree is a happier tree,” she said.
She emphasized optimizing water use rather than deficit irrigation scheduling. In orchard rows, that includes precision monitoring for specific cultivars. At the orchard level, that includes use of precision irrigation, using lysimetry or UAVs for monitoring on a daily or weekly basis.
Optimized irrigation or controlled deficits can be strategies on the orchard level with monitoring by aerial sensing. Moving to the groundwater basin level, managed aquifer recharge, groundwater banking and public-private partnerships can be used.
Nocco cited the T-REX project, Tree
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Crop Remote Sensing of Evapotranspiration Experiment, to help growers further optimize water use in orchards.
Automation to collect measurements of stem water potential, daily estimates of actual ET at the tree scale using drones or satellite data or methods to monitor stress responses are some of the long-term goals of the project which is funded by the Almond Board and CDFA.
Tools include drones, hyperspectral imagery, eddy covariance systems and field-based observations and measurements of radiometric canopy temperature, stem water potential, photosynthesis and actual ET.
On a much larger scale, managed aquifer recharge capturing flood water, using remote sensing for site suitability and orchard response are also tools to manage irrigation water.
Tom Devol, Almond Board’s senior manager of field outreach and education, noted that simple tests for distribution uniformity in an irrigation system have the potential to save money.
“DU can have a big impact on the bottom line,” Devol said. “Testing is recommended at least once every three years.”
Common causes of non-uniformity in an irrigation system are clogged emitters, system leaks and mixed nozzles. The goal is to operate the system at 95% efficiency. Most pres-
surized systems are operating at 85% or less, Devol said.
Almond Board partners with Resource Conservation Districts across the state to promote DU testing with mobile irrigation laboratories. Kevin Greer, who operates a mobile lab out of the Red Bluff area, said when you put numbers to system inefficiencies, you can see where money is lost.
A missing sprinkler at 0.87 gpm is 52.2 gallons per hour. That equals 1,253 gallons lost in a 24-hour set and 18,792 gallons a year at 20 sets. Improper line repairs, leaks at filters and clogged screens all add up to lost water and yield losses.
Rising costs of nutrients will mean almond growers must make do with less, UC researcher Patrick Brown said in a panel discussion at the Almond Conference. Applying nutrients correctly is the number-one way to save costs, he added.
Nitrogen and potassium are the macronutrients most important for production. Zinc and boron lead the list of micronutrients that must be managed. Phosphorus and calcium are macro nutrients that must be monitored and applied when necessary.
Brown recommended optimizing nitrogen and potassium with a nutrient budget approach: Supplying them at the right time and the right amount. That means matching supply with tree demand and considering all inputs, including nitrogen in irrigation water and residual soil nitrogen. Applications also need to be done when roots are active.
“Always start when trees are hungry,” Brown said. Knowing yields will help in determining the amounts of nitrogen. Research has shown that in mature almond trees, from dormancy to mid leaf-out, there is very little N uptake. Uptake begins at mid leaf-out and is essentially complete by hull split. New numbers from the Almond Board show N demand from first leaf to maturity. At first leaf, the total non-yield N demand directed to leaves and woody biomass is 30 lbs. By third leaf, total non-yield N demand is at 65 pounds plus the expected yield times 0.068.
Brown said that differences between years, orchard zones and cultivars impact N decisions.
Potassium is the most expensive nutrient, but almost identical to N in timing and demand.
In N decision making, Brown said to always have a cultivar-specific, yield-driven fertilization strategy. That requires prediction and in-season adaptation. In-field variability
should be identified and corrected by investing in correcting local nutrient deficiencies and fertigation system optimization. He noted that N is not retained well between seasons in low-organic-matter soils, and a uniform field N rate cannot be efficient.
Yield mapping can be a tremendous tool in almond production, Brown said. Yield determines both N and K demand. Brown noted that cultivars and orchard zones differ in productivity and nutrient demand. Unlike N, K is not lost below the root zone, but
remains in the system for future use. Reducing K applications in these areas is possible, Brown said. He also warned that measuring and interpreting soil and tissue K is more difficult than any other element.
Almond hulls and shells can serve as nutrient sources, potentially saving in fertilizer costs. Brown said that at current prices, using hulls and shells at 4 tons per acre to return N and K to orchards can save $300 in N and K alone, but there are the added benefits of increased soil health and water retention.
“Increase efficiency, don’t cut nutrients,” panelist Tommy Bottoms said. Bottoms, who is with Timothy and Viguie Farming and El Molino Farms, noted that fertigation will always be worse in terms of efficiency than irrigation.
He advised taking a close look at the actual irrigation system and determining its level of performance, sampling water to determine nutrient output and correcting problems.
Bottoms also stressed the value of
developing a nutrition management team. A significant portion of the production budget is in the hands of those responsible for feeding the trees. They should look at other orchards, both good and bad, and develop a sense of ownership. After irrigation schedules and fertilizer amounts, the check list includes determining fertilizer run times, starting the pump and checking for leaks and pressures.
“Calculate, measure and check again. Monitor tank levels,” Bottoms said. To achieve continuous improvement, understand crop demand and move toward continuous fertigation by using high-frequency, low-volume applications, improving estimation of tree yield and recognizing opportunity cost. Bottoms said that if automation is part of the solution, it must be made cheaper and easier to implement.
By JULIE R. JOHNSON | Contributing Writer
UCCE Orchards Advisor Luke Milliron shared what he believes are the highest priorities for successfully growing almonds and walnuts during his North Valley Nut Conference presentation in January at the Silver Dollar Fairgrounds in Chico, Calif.
“What it really gets to, are you a risk-taker or are you riskaverse, that is what it really comes down to,” Milliron said.
His presentation covered four different subjects: almond/ walnut rootstocks, walnut rootstock weaknesses, water and freeze.
“These are the things that have massive financial implications,” Milliron said.
He went on to add, “What we are talking about in difference here concerning what rootstock you plant can be a 1000to 2000-pound difference in a single year. We are talking about hundreds of thousands of dollars of income in a short time span.”
Almonds
“As Roger Duncan, who’s done the most research at UC, will say, rootstock selection is by far the most important decision when planting; it is a lot more important than variety,” Milliron said.
He encouraged growers to not select by default or “to not make the decision on what rootstock to choose based on what their neighbors are planting.”
Milliron encouraged when making rootstock selection to make it site-specific, or based on the physical, chemical and biological conditions of the site.
His presentation focused for almonds on Krymsk 86 (K86)-peach x plum; Viking-peach, almond, plum, apricot complex; and peach x almond hyrids such as Hansen 536, Titan SG1 and Nickels.
“If you are a farmer in the north state, anchorage and wet feet are the two highest priorities for most of our almond farmers,” Milliron said.
He noted with anchorage, K86 has become the default goto due to its “incredible” anchorage capabilities, with Viking coming in close second.
However, with K86, he cautioned that while it is good for anchorage, wet feet and moderate vigor, it has problems with salinity, nematodes (particularly root-knot) and compatibility issues with some varieties such as Monterey, Independence and a few others.
“As for phytophthora, it isn’t great, but at this point when it comes to phytophthora, we don’t have a lot of great options,” Milliron said.
He advised growers to check for rot-knot nematodes at a
site before planting K86 as it is the worst in susceptibility.
Referring to a boron trial by Katherine Jarvis-Shean, UCCE orchard systems advisor in the South Sacramento Valley, Milliron said peach-almond hybrid rootstock, such as Titan SG1 and Nickels, consistently had the highest yield; however, due to salinity, K86 and Lovell did very poorly.
“Viking is a rootstock I am very intrigued by,” Milliron added.
In anchorage it is second to K86, has moderate vigor, relative salt tolerance including boron (but not as good as the peach almond hybirds), does well under some nematode conditions, and does well in high-pH/alkali soil.
Viking’s yield compared to K86 is questionable. Some growers believe
K86 provides a better yield.
It is somewhat susceptible to phytophthora and compared to K86 does have issues with wet feet.
“I like peach/almond hybrids, but we don’t plant a lot of them because we are so concerned about anchorage and wet feet, and maybe with wet feet we should be more concerned about phytophthora, and peach/almond hybrids are often the worst about phytophthora,” Milliron said.The hybrid is also weak in the areas of crown gall, lesion and ring nematode and bacterial canker.
However, Milliron explained, on the plus side, he has found this hybrid to be very vigorous and get much higher yields than many other rootstocks.Peach/almond hybrid is also salt tolerant including boron, resistant to root knot nematode and does well in high-pH/alkali soil.
“You can’t ignore those results,” Milliron said.
In a Nickels Soil Lab trial, 25th leaf trees with peach/almond hybrids and Viking rootstocks “held value the longest.”
Research conducted by Franz Niederholzer, Ph.D., UCCE orchard systems advisor, has shown plum and rootstocks with plum, such as K86 and Rootpac-R, can have compatibility issues with some varieties, namely Monterey to some extent and definitely Independence.
Quoting Bill Burchell, Milliron said, “It takes 20 years to prove a variety. And I would add rootstock and new rootstock/variety combos to that.”
He added, if a grower is risk-averse, plant next what’s been most profitable for you over the past 20-plus years.
“What is giving you the most profit on a year-in-year-out basis, maybe just stick with that as there is risk to planting something that doesn’t have that 20-year track record,” Milliron explained. “I would much rather do the trial for you and being the researcher and finding out that something is problematic.”
He talked about the current almond variety trial at the California State University, Chico farm.
“In addition to what we currently have, we will be planting this winter another 30 new varieties to start testing,” he said.
Right out the gate when talking about walnut rootstocks, Milliron said, “Please, don’t plant Paradox seedling. It is so susceptible to phytophthora and crown gall. I would really point toward the new clonals as the way to go.”
When selecting a rootstock, he suggests first looking at the problems that may arise, such as blackline, phytophthora, nematodes and crown gall.
The problem/rootstock:
Blackline: own-rooted English
Phytophthora: RX1
Nematodes: VX211
Crown gall: RX1, Black
Salinity: Black as a possibility
For potential planting sites with oak root fungus, Milliron suggests focusing on other problems. “For waterlogging,
we just don’t have anything yet,” he said. “For most situations, I would plant RX1 or VX211. Both have good vigor and less crown gall.”
Although there is little data currently on the Grizzly variety, Milliron finds it to be “very promising.”
Milliron encouraged growers to use county Resource Conservation District Mobile Irrigation labs.
“Free system evaluations are available through several counties,” he explained. For help contact:
Tehama, Shasta, Butte, Glenn counties: Kevin Greer, 530727-1297 or kevin@tehamacountyrcd.org.
Yolo County: Conor Higgins, higgins@yolorcd.org
Solano County: Kevin Young-Lai, kevin.young-lai@solanorcd.org
Sutter-Yuba-Colusa counties: Karandave Kang, karandeavek@gmail.com
“If you have your water spraying every which way, then none of the rest of your efforts matter at all. And when you try to do cross protection, you will really be in trouble,” Milliron added.
Another focus was pressure chambers.
“I am a big proponent,” he said. “Water status has huge growth, yield and tree health consequences. I think asking the tree what it is experiencing in terms of water, there is no substitute for doing that.”
Milliron referred to a water trial by Integrated Orchard Systems Specialist Bruce Lampinen and said at the end of the eight-year trial, trees at 16 bars hadn’t filled half the space versus trees at 8 bars were at maturity.
“What that means is for an 80-acre orchard, just 4 bars of stress can have a difference that equals out to $443,520 loss to the grower,” he said.
Walnut: Irrigate at 2 or 3 bars drier than the fully watered baseline.
Almond: Irrigate at 2 to 4 bars drier.
Milliron went on to explain, however, more water isn’t always better. “For instance, you give a walnut tree a little too much water and you get a canopy that just starts collapsing in on you.”
In addition, too much water is just asking for phytophthora, which moves with water. “Watch your irrigation set length. Avoid ponding and keep water off the trucks,” he emphasized.
To help avoid water problems, Milliron reminded growers of cultural management in the orchard (use stream-splitters, avoid sprinklers contacting low scaffold and plant on berms) with the question, “Can soil infiltration be improved with
amendments or cover crops?”
Check soil moisture and distribution uniformity and pay attention to the beginning and end of the season were his final remarks on water.
“Don’t water until the tree tells you it needs it. In the spring, you will see your neighbors already watering, but if your trees say they don’t need it yet, wait until they do,” Milliron said.
Milliron shared six steps to prepare for sudden autumn freeze:
August: Fertilizer cut-off.
September: For young trees, withhold irrigation until terminal bud sets.
If rains haven’t come, irrigate going into November. October to December and April: Monitor soil moisture and weather.
If a freeze is predicted and soil is dry, it should be wetted two to three days prior.
If a grower has the capability, consider active frost protection with solid-set irrigation.
If a grower does suspect damage, Milliron advised to cut into the branches as soon as possible and check for drying or browning.
If damage does occur, paint the southwest side of the damaged trees with 50% diluted (1:1 water to paint) white interior latex paint.
If trees don’t leaf out in April as expected, look back at temperature records. “Was there a sudden autumn freeze?” Milliron asked.
Don’t overreact. Wait, Milliron stressed.
“Provide water starting in May, nutrition, treat for sunburn and wait to prune,” he said. “You will often see delayed leaf out on blank wood. Do start pruning by summer and cutting out the dead wood and, if at all possible, burn it to avoid Bot or Phomopsis.”
He invited those attending the conference to listen to the podcast “Growing the Valley” created by Milliron and Dr. Phoebe Gordon, farm advisor in Madera, produced through UCCE and available on its website, growingthevalleypodcast. com.
The recent series of atmospheric rivers have dumped enough rain and snow on Northern California to give us hope that the end of the drought may be near. California’s Department of Water Resources is reporting that Central San Joaquin precipitation at the end of January was 177% of normal, year-to-date, and 84% of normal for the entire water year with two potentially wet months still ahead. According to Department officials, the 2022-23 water year, so far, is “the best start to the snowpack in over a decade.”
Additional evidence of this year’s water supply bounty is the tremendous amount of water flowing through the Sacramento/San Joaquin Delta out to the Pacific Ocean. The region depends on this outflow for ecosystem health and to reduce salinity in the Delta where many Bay Area communities get their water. The amount of outflow was so abundant in early January news
writers throughout California were asking why more wasn’t being done to capture the abundant supplies.
That’s the good news.
The bad news, especially for communities in the San Joaquin Valley, millions of acres of the country’s most
productive farmland, and the consumers who depend on it, is that we aren’t doing enough to capture these flood flows when they’re available. That’s because a set of calendar-based regulations set limits on how much water can be captured, even if trees are being toppled and water is flowing over the banks of creeks and streams.
On Jan. 16, Bay-Delta outflow peaked at over 172,500 cfs (cubic-feet per second), while export pumping had ranged from just 6,500 cfs to about 8,500 cfs due to environmental restrictions intended to protect Delta smelt. That day, exports began to rise, reaching near capacity of 13,890 cfs on January 24. If water system operators had the flexibility to safely increase pumping earlier in the month, an additional 200,000 acre-feet could possibly have been captured and stored for use later in the year.
The rule preventing us from saving more of this near-biblical amount of water is based on fish behavior under certain historic conditions. How-
ever, we are clearly living through exceptional circumstances, and the rules and rule makers are utterly incapable of adjusting, which could be the difference between these storms taking us out of drought instead of suffering through another dry year.
Instead of relying on real-time data, like almost all other decisions we make, California’s water regulators are held to a specific set of rules based on arbitrary dates on the calendar or one-time occurrences in the Delta. The pumps that are in place to deliver water to farms, homes and businesses are currently running at half of their capacity, even though billions of gallons of water are flowing out to the ocean, far more than the State’s environmental regulations require.
As California struggles to recover from three years of intensive drought, and the San Joaquin Valley desperately
tries to restore its groundwater supplies, this management of such a scarce resource is mystifying given how much water is available right now.
Anyone who has spent enough time in California understands how fickle our water supply can be. Our changing climate is delivering wetter wet years and hotter dry years than in decades past. There are enormous opportunities to build the infrastructure needed to capture flood flows like the ones we’ve experienced so far this year.
Both the state and federal governments have made funding available to repair our existing infrastructure and to build new projects, such as wisely placed new or enlarged reservoirs to capture high storm flows like the ones we saw in January. New canals and pipelines can carry the water we’ve saved to areas in the San Joaquin Valley where they can be stored underground, replenishing the region’s groundwater.
Diverting water during these peaks gives us the opportunity to share in the
abundance that is benefiting California’s natural environment. The fact that we can share this abundance also provides the necessary resources to keep our farmers farming and delivering the safe, local and affordable food California families depend on when they visit the grocery store.
And we need updated policies and projects designed for the 21st century, with functional flows, new spawning areas and habitat for young fish instead of a calendar-based approach funneling flows through channelized water ways that provide little if any ecosystem benefits.
Rather than accepting our changing climate as an inevitable path to scarcity and relegating vast parts of our state to perpetual water shortages, we believe better, science-based management is the key to future water supply abundance for all Californians.
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