California Ag Network

Tag: UC Davis

  • Grapevine Red Blotch Update from UC Davis Foundation Plant Services

    Foundation Plant Services (FPS) has been testing grapevines in its foundation vineyards for grapevine red blotch virus (GRBV) since 2013. Red blotch infection rates have remained extremely low in the Classic Foundation Vineyard, ranging from 0% to 0.21% since 2013. None of the 4,270 vines were infected in 2020 (see table). Russell Ranch Vineyard (RRV) remained unaffected until 2017 when five of 4,132 vines, only 0.1%, were infected with GRBV. Since then, despite significant efforts to prevent the occurrence of the disease, the infection rate in the vineyard has increased to 0.5% (24 of 4,406) in 2018, 7.1% (339 of 4,761) in 2019, and 18% (788 of 4,367) in 2020 (see table).

    Since the discovery of red blotch in the foundation vineyards, all propagated vines related to the positive vines tested negative in every case, indicating the incidence of red blotch at RRV is due to field transmission of GRBV. In addition, material from these plants was distributed prior to the last negative test date, suggesting that material was GRBV-free at the time of distribution. In 2018, we implemented a test-to-order policy that further ensure orders being shipped were negative just prior to distribution.

    One of the greatest challenges in managing red blotch has been vector-mediated transmission. The three-cornered alfalfa hopper, Spissistilus festinus, has been documented as a vector in greenhouse studies and has been found in RRV. Given this threat, we have implemented more frequent vineyard inspections and additional spray treatments specifically targeting the vector and developed a comprehensive program for control of this vector. However, it remains unknown if other vectors are involved in the transmission of red blotch. We are working closely with University of California scientists to monitor the foundation vineyards for potential vectors and track the spread of the virus.

    Given the level of red blotch infection in Russell Ranch Vineyard, we feel the best course of action is to discontinue distributing material from RRV. However, grapevine material from the Classic Foundation Vineyard, which represents the majority of clonal families from RRV, will continue to be available for distribution and is tested for GRBV as dormant canes prior to shipping.

    FPS is greatly committed to maintaining the highest testing standard for our foundation vineyards. We will continue to test all vines in the foundation vineyards individually on an annual basis and implement the best management strategies to safeguard foundation material. In addition, FPS has begun working

    with UC Davis planners to design a 24,000 square foot ‘Emergency Greenhouse’ that will protect approximately 4,000 of FPS’ most valued Foundation grapevines. This is essential to protect the material from vectors and guarantees immediate access to the clean plant material in case of field infection. FPS is currently renting two 1,100 sq ft greenhouses in the interim from the College of Agricultural and Environmental Sciences to temporarily house the most valuable clonal selections as newly propagated virus-tested mother vines in a protected environment.

    Moving forward, a collaborative approach between FPS and the grape industry is needed to protect grapevine Foundation material from exposure to viruses. Although there are major knowledge gaps about the transmission and epidemiology of grapevine red blotch virus, well-funded research teams around the country are working on elucidating the biology. In the meantime, FPS is moving forward to ensure protection of the core grape Foundation which is an essential asset to the US grape industry. — By Deborah Golino (FPS Director dagolino@ucdavis.edu) & Maher Al Rwahnih (Director of Laboratories malrwahnih@ucdavis.edu)

  • Main Fungal Canker Diseases Affecting California Almonds

    In California, fungal canker diseases have long been known to affect almond trees. However, they have become an increasing concern to growers in recent years as they are affecting a greater extent of young trees, eventually resulting in significant tree losses. Canker diseases can also become prevalent in mature orchards, impacting yield, the lifespan of trees, production costs and overall profitability of almond orchards. Ultimately, trunk and scaffold canker diseases constitute a major cause of tree death and branch dieback in California almond orchards.

    As the University of California (UC) Assistant Cooperative Extension Specialist in Plant Pathology for fruit and nut crops when I receive calls from farm advisors, almond growers and Pest Control Advisers (PCAs) the questions they most frequently have are in relation to canker diseases, asking how can it be diagnosed, and how can it be treated.

    Symptoms on affected trees are very conspicuous and often alarming to growers. Moreover, field diagnosis of canker diseases is difficult as symptom delineation among the various canker diseases is not clear. Hence, laboratory tests are usually required to obtain accurate disease diagnosis, which is essential to the implementation of appropriate management strategies.

    With support from the Almond Board of California (ABC) and with the help of farm advisors, my laboratory conducted statewide surveys to characterize canker diseases in almond orchards and to get a thorough understanding of the main diseases and pathogens present. This work has provided molecular tools and a database for the accurate identification of fungi commonly isolated from almond cankers.

    This article will provide an overview of the main canker diseases that impact almond trees and how they can be recognized. But first, let’s review some general concepts about canker diseases.

    What is a canker?

    A canker in woody plants generally refers to a lesion produced in the bark of a plant’s stem, twig, or branch, often resulting in a dead area that can block water and nutrient transport to portions of the tree, thus causing parts of the plant to die back. Most cankers are caused by fungi, which invade bark tissue and the current season’s wood. However, some fungi colonize in both bark and internal wood tissue, causing canker rot or wood cankers that persist for years.

    Wood cankers typically consist of brown-to-dark brown discoloration of xylem tissues and may vary in shape from wedge-shaped to round, or irregular. 

    What are the main infection pathways and disease cycles of canker diseases?

    In orchard systems, cankers usually originate around wounds such as pruning wounds, mechanical injuries, sunscald and sunburn lesions, as well as wounds caused by insect borers. In almonds, canker pathogens infect trees mainly through pruning wounds made for primary and secondary scaffold selection to provide the general structure of trees. Cracks in the tree crotch or on the trunk as well as shaker injuries provide other entry points for canker-causing pathogens in almonds. Canker diseases may go unnoticed during the early stages of infection, though symptoms become more visible as the trees age.

    Most fungal canker pathogens produce fruiting bodies on dead wood of infected host plants. The spores produced by these fruiting bodies serve as inoculum for new infections, mostly during wet weather. The vegetation present in the vicinity of orchards, particularly trees in riparian areas or neighboring orchards of susceptible crops, may serve as inoculum sources for fungal canker pathogens affecting almonds. Once a canker disease has been established in an orchard, infected almond trees can provide additional inoculum for further infection. 

    Does stress play a role in the exacerbation of canker disease?

    Recent outbreaks of canker diseases in perennial crops have been attributed in part to drastic changes in production practices, climate change and increased plant stress, the continuing adaptation of pathogens to new environments, and, most importantly, the global movement of plant material. Ultimately, though, trees suffering environmental stresses are more susceptible to canker diseases.

    Microorganisms that usually do not cause disease in non-stressed hosts may become opportunistic pathogens of stressed plants. Increases in canker diseases are common during extended periods of drought or following sudden temperature fluctuations. Drought stress can also impair the plant’s ability to defend against fungal invasion. Conversely, excessive watering can kill roots and predispose plants to canker pathogens.

    What are the main canker diseases in California almonds, and what are their symptoms?

    Ceratocystis canker

    Ceratocystis canker, caused by the fungal pathogen Ceratocystis destructans (formerly known as Ceratocystis fimbriata), is one of the most prevalent canker diseases in California almonds – it occurs statewide in all almond producing counties. While this disease is generally associated with shaker damage and bark injuries on trunks during harvest, C. destructans is also capable of infecting branches from fresh pruning wounds and if left untreated can kill branches, scaffolds and entire trees. Ceratocystis is spread by several species of sap-feeding beetles and fruit flies.

    Ceratocystis canker starts as water-soaked injuries that are darker than the surrounding healthy tissue. Symptoms of established infections include amber-colored gumballs that are produced around the margin of the canker, where the fungus is most active. The cankers are perennial, persist over several years, and are most active during the growing season. Young trees infected with Ceratocystis canker may die rapidly while infections in older trees usually progress slowly. 

    Band canker and other Botryosphaeriaceae cankers

    Although band canker was first reported years ago as a disease in almonds, it’s appearance had been very sporadic up until the last decade, when this disease was suddenly being reported in large numbers of commercial orchards and causing severe damage.

    Band canker

    Band canker produces unique symptoms that include oozing amber sap that forms in a ring around the circumference of the tree. Young, vigorous varieties that grow quickly from aggressive nitrogen and water inputs are especially prone to band canker. Solid sprinkler irrigation or micro-sprinklers that wet the tree trunk can create conditions favorable for infection.

    Band canker is often an annual disease that occurs when trees are in their second-to-fifth leaf and usually does not necessarily reappear the following year. However, an increasing number of cases have been reported lately where cankers are being re-activated in following year. Tree death due to band canker has become more common as multiple bands can develop as the canker continues to grow from one growing season to the next.

    Botryosphaeriaceae cankers are characterized also by gumming around pruning wounds made near the trunk or in main scaffold branches. Band canker and Botryosphaeriaceae cankers are particularly common in young almond orchards in the northern San Joaquin Valley and well as in the Sacramento Valley.

    Infections by Botryosphaeriaceae fungi are usually associated with growth cracks or pruning wounds on the trunk and main scaffold branches. Studies have revealed there are at least 12 different Botryosphaeriaceae species in almonds, each with various levels of virulence. Among them, Neofusicoccum species, including N. parvum and N. mediterraneum, are the most common in California. Neoscytalidium dimidiatum also occurs frequently in cankers developing around pruning wounds on the trunk. This pathogen also can cause shoot blight and fruit rot in almonds.

    Eutypa dieback

    Eutypa dieback in almonds occurs sporadically in the Sacramento Valley and in the northern San Joachim Valley. Eutypa dieback is caused by the fungus Eutypa lata and is a common disease in apricots, sweet cherries and grapevines. Eutypa dieback in almonds is usually found in young trees.

    Cankers mostly originate from pruning wounds on limbs or trunks as well as from cracks formed at the junction of scaffold branches and the trunk, extending downward toward the graft union or upwards into one or more scaffold branches. Amber-colored gum turning dark brown to reddish brown normally exudes around the cracks. Irregular-shaped to wedge-shaped, brown-colored cankers are observed from cross sections of limbs and trunks.

    Limb dieback may occur several months or years after infection. The fungal fruiting bodies, i.e. the perithecia of E. lata. are rare in almond orchards, suggesting sources of inoculum for this disease most likely originate from surrounding susceptible hosts including apricot and grapevine as well as natural host plants in riparian areas such as willows. 

    Cytospora cankers

    Cytospora species have been isolated sporadically in almond orchards in California, Cytospora canker is generally associated with pruning wounds in the branches of third-leaf trees or older. At least five species of Cytospora have been associated with cankers in California almonds. Symptoms of Cytospora canker include longitudinal cankers in branches and scaffolds often associated with pruning wounds, vascular discoloration of the wood and moderate gumming.

    Florent Trouillas, UC Davis Plant Pathologist

    Cytospora species have been traditionally thought to be secondary to sunburn and other stresses or injury in stone fruits. However, their prevalence in cankers together with pathogenicity studies suggest that this group of fungi constitutes virulent pathogens. Overall, Cytospora pathogens are of increasing concern in recent years in many fruit and nut crops in California.— By Florent P. Trouillas (Through the Almond Board of California), Assistant Cooperative Extension Specialist in the Department of Plant Pathology at the University of California, Davis

    Stay tuned for a follow-up article from Trouillas on how growers can manage different types of canker diseases in their orchards. Growers are also encouraged to check out the Univeristy of California IPM website for more information on various types of canker diseases.

  • Whitehall Lane Winery Released the First-Ever Camminare Noir and Paseante Noir Wines Made from California’s Newest Sustainable Grape Varieties Developed at UC Davis

    Dr. Andrew Walker, UC Davis Professor of Viticulture & Enology (Geneticist)

    These red wines were 20 years in the making; or rather, the grape vines took two decades to develop. Whitehall Lane joined forces with Dr. Andrew Walker of UC Davis and Dr. Paul Skinner of Vineyard Investigations in Napa Valley and planted these experimental grape varieties because they are highly resistant to Pierce’s disease. Pierce’s disease is caused by a bacterium spread by leafhopper insects called sharpshooters. It infects grape vines across the US and costs California grape growers more than $100 million per year.

    “These varieties will hopefully make viticulture much more sustainable and provide a high-quality wine that the industry will welcome,” said Walker. Whitehall Lane owner Katie Leonardini agrees with Walker adding, “Rather than trying to manage the sharpshooter with insecticides and potentially harming other beneficial insects, these new rootstocks dovetail into our sustainable and green practices. And the wine is outstanding too!”

    Whitehall Lane bottled the 2019 Camminare Noir and 2019 Paseante Noir wines as single, distinct varietals. These grapes from the winery’s Oak Glen Vineyard were harvested on October 15, 2019. Winemaker Jason Moulton kept the two small lots separate saying, “It was amazing how distinct these two wines were from color to flavor to texture.” He continued, “As they developed in our custom American oak barrels, it was evident that these were excellent stand-alone wines.”  The special American oak barrels were designed by Nadalie Cooperage in Calistoga, CA to specifically suit the characteristics of these new American wines.

    The Camminare Noir profile is a cross between Petite Sirah and Cabernet Sauvignon and the wine has aromas and flavors of blackberries, raspberries, cherries and a dense tannin profile. The Paseante Noir is a combination of Zinfandel, Petite Sirah, and Cabernet Sauvignon and delivers flavors of cassis, coffee, and berry.  Fewer than 25 cases of each were made and are available at the winery.

    Whitehall Lane planted the two rootstocks in 2016 in their Oak Glen Vineyard. Dr. Walker, professor of viticulture and enology at UC Davis, developed the rootstock, creating grape varieties that provide high-quality wine while elevating the level of sustainable grape growing. “Whitehall Lane was constantly replanting dead vines infected by Pierce’s disease,” said Dr. Skinner. “I knew the Oak Glen vineyard was a perfect location for Walker’s experimental varieties.”

    Whitehall Lane Winery is a family-owned and operated winery in Napa Valley’s historic Rutherford Appellation. They are dedicated to growing and making premium Cabernet Sauvignon, Merlot, Sauvignon Blanc, Chardonnay and Pinot Noir wines from their eight estate vineyards.  They provide friendly hospitality at their Napa Valley winery and are Napa Green winery and vineyard certified with sustainable practices.

    Dr. Walker is a faculty member of the Department of Viticulture and Enology at UC Davis. His lab is actively involved in breeding wine grapes for resistance to Pierce’s disease.

  • UC Davis Wants Samples of Your Fermented Foods for Science

    It’s not always easy to find silver linings during the COVID-19 pandemic, but here’s one that food scientists at the University of California, Davis, have discovered: More people are exploring the ancient art of fermented foods.

    “My mom made her first batch of sauerkraut this summer,” said Maria Marco, a microbiologist and food science professor with the UC Davis College of Agricultural and Environmental Sciences. “With so many of us sheltering-in-place, fermented foods are more popular than ever.”

    Marco takes more than a culinary interest in America’s latest food trend. Marco and Erin DiCaprio, a food safety expert and Cooperative Extension specialist at UC Davis, are investigating the microbial mysteries of fermented fruits and vegetables to better understand the role fermentation can play in healthy diets.

    And you can help.

    “We’re calling on people from across the state to send us samples of their home ferments so we can characterize their microbial composition,” Marco said. “Citizen scientists can help us expand the body of knowledge about the nutritional content and beneficial bacteria in fermented fruits and vegetables.”

    Marco, DiCaprio and their team of mostly undergraduate student scientists are looking for “fresh” ferments that are composed mainly of fruits and vegetables. By fresh, they mean samples taken right after fermentation, before refrigeration. They will be collecting samples for the next year. If you live in the Davis or Sacramento area, they can arrange to pick up your sample. If you live outside the area, or want to learn more, contact the team at EAT LAC (as in, lactic acid).

    Managing microbes

    Fermented foods and beverages are produced by nurturing conditions that discourage the growth of harmful bacteria and encourage the growth of beneficial microorganisms. Take sauerkraut, for example. When you combine cabbage, salt, time and the right temperatures, you can help friendly microbes flourish. As they do, they convert sugars in the cabbage into lactic acid and other compounds with tangy flavor that keep harmful bacteria at bay.

    Similar chemistry is at work when producing a long list of fermented foods, such as yogurt, cheese, bread, alcohol, chocolate, coffee, salami, vinegar, kimchi, miso, tempeh and pozol.

    Besides adding new flavors and textures, fermentation can extend the shelf life of food, improve our ability to absorb some nutrients and — perhaps — provide an environment for beneficial bacteria to thrive in our digestive systems and help prevent chronic disease.

    “It’s quite possible that consuming fermented foods as part of a regular diet supports a healthy digestive tract and the microorganisms living in our intestine,” Marco said. “Our health may be helped by what those microbes eat, as well as by the nutrients they produce. Our goal is to provide solid evidence that can show whether fermented foods can, indeed, help fight disease. And if so, how.”

    Tips for fermenting safely at home 

    What’s the best way to ferment fruits and vegetables at home? DiCaprio is working with the UC Master Food Preserver Program to provide online fermentation classes.

    In the meantime, here are DiCaprio’s top tips:

    • Follow a research-based recipe, like the ones you can find at UC Food Safety, the USDA Complete Guide to Canning and the National Center for Home Food Preservation. “Some of the resources available online and in print haven’t been vetted for safety,” DiCaprio said. “They might not have you add enough salt in the beginning, for example, which is important for keeping your product from spoiling.”
    • Sanitation matters: Keep hands, equipment and the preparation area clean and sterile throughout the fermentation process.
    • Control temperature: Don’t let your ingredients get too hot or too cold.
    • Monitor the process to make sure it’s fermenting properly — that little bubbles are slowly rising to the surface, for example, and that mold isn’t growing throughout the container. “You can’t just set something on a counter and forget about it,” DiCaprio noted.
    • Skim the scum. It’s common for a layer of yeast and mold to form atop your vegetable brine after a few days. DiCaprio recommends skimming it off each day.

    “And be sure to start with good, fresh ingredients,” DiCaprio said. “We look forward to seeing the samples!” — By Diane Nelson, UC Davis, Food & Agriculture

    Purple cabbage used to make sauerkraut changes to a light pink color as it starts to ferment. (Hector Amezcua/UC Davis)

  • CDFA & UC Davis Collaborate to Assist Commercial Laboratories Testing Smoke Impact in Wine Grapes

    The California Department of Food and Agriculture (CDFA), the UC Davis Department of Viticulture and Enology, and the UC Davis College of Agricultural and Environmental Sciences are offering laboratory services, with limited capacity, to test winegrapes and wine for the presence of smoke compounds due to recent wildfires. In addition to commercial laboratories already performing tests, these laboratories are offering limited services to hopefully reduce testing turnaround times.

    “We are hearing many growers and grower representatives voice concern over lab turnaround time, as lab results are needed to make a decision about harvesting their winegrapes or to assess the resulting wines,” said CDFA Secretary Karen Ross. “To answer a need in our world-renown California wine industry, CDFA is proud to partner with UC Davis to offer the resources of our laboratories.”

    “The wine and grape industries of California are important to the state and to our college, “ said Helene Dillard, Dean of the College of Agricultural and Environmental Sciences at UC Davis.  “The wildfires this year have been particularly devastating, so we are very happy to be partnering with the CDFA to apply our collective resources to this important issue.”

    “Our staff members are working diligently to meet the laboratory needs of the wine and winegrape industries resulting from the unprecedented number of wildfires on the west coast,” said Gordon Burns, CEO of ETS Laboratories. “We appreciate the partnership of CDFA and UC Davis as we work together to answer industry needs.”

    CDFA’s Center for Analytical Chemistry (CAC) is offering grape analysis. CDFA’s limited testing capacity is estimated to be 30-50 samples per day, with a turnaround time of 3-5 days, as long as a backlog does not occur. If a backlog does occur and the turnaround time will be longer, CDFA will provide that information on its website.

    The UC Davis laboratories are teaming-up to provide wine analysis.

    While the analytical methods of the CDFA and UC Davis labs have been validated and are accurate, the methods are not ISO 17025 (International Organization for Standardization) accredited. Therefore, growers should verify with insurance providers and/or legal counsel that the results will be acceptable before submitting samples. The laboratories will measure seven smoke-related compounds (guaiacol, 4-methylguaiacol, o-cresol, p-cresol, m-cresol, syringol, and 4-methylsyringol).

    To submit grape samples, visit the CDFA laboratory website for sample submission instructions, or contact CDFA at CDFA.CAC_receiving@cdfa.ca.gov or (916) 228-6844. Price per grape sample is $246.

    To submit wine samples, visit the UC Davis laboratory website for more information. Price per wine sample is $150.

  • Report Provides Data on New Almond Varieties

    Almond Board of California—Innovation always has been part of the almond industry. That includes exciting research about new almond varieties intended to meet the changing needs of consumers, end buyers and fast-growing export markets.

    There are about 70 different varieties of almonds grown around the world. California orchards produce about 30 varieties, though 13 of them – with Nonpareil dominating – account for 98% of what is regularly grown. While other countries may grow multiple other varieties, when it comes to total production California remains on top, producing more than 80% of the world’s almonds and supplying millions of pounds annually to more than 90 export markets.

    Still, California growers and handlers must continue to adapt to provide almonds that satisfy shifting consumer appetites, end-buyer demands and other market forces. What a confectionery business or chocolatier wants in an almond can vary greatly from what someone snacking in India or China wants, which can differ largely from what a company producing almond milk in the U.S. wants.

    The diverse uses for almonds and ever-changing preferences continue to influence demand for specific kernel characteristics such as flavor, appearance, shape, texture and color. Similarly, to continue improving not only what we grow but how we grow, the industry is looking into almond varieties that check horticultural boxes, including the ability to produce more pounds per light intercepted and self-compatibility.

    Recognizing the need to constantly innovate and maintain high demand for California almonds, the Almond Board of California (ABC) began funding almond variety development research in the early 1970s and expanded that effort in the late 1980s to include rootstock breeding. Over the past 20 years, this research has delivered five new University of California (UC) varieties – Padre, Sonora, Kester, Winters and Sweetheart – and supported testing of most commercial varieties and rootstocks for overall performance, resistance to pests, diseases and abiotic stresses. The research has kept California on the cutting edge of almond production globally.

    Now, for the first time, decades of data and results from ABC’s first-ever Crack Out Day (an event held last November at which industry members tasted and compared more than 60 almond varieties from around the globe) have been pulled together in a comprehensive breeding report. For growers looking to replant their orchards as well as nurseries and private breeders, the report offers critical information about the performance and potential promise of different almond varieties.

    “The California almond industry is always looking for better and more sustainable almond varieties,” said Sebastian Saa, ABC’s associate director of Agricultural Research. “We’re convinced that through research and innovation, we’ll find varieties that produce not only more pounds of almonds, but also higher quality with reduced management costs and horticultural inputs in terms of water use, pest management and more. As technology and experience advance, it will allow us to discover better, more efficient varieties.”

    Saa listed the following as some of the key takeaways and learnings provided by the report:

    • The growing number of self-compatible varieties being developed globally.
    • Spanish varieties are mostly hard shell, but some new selections are soft shell and should be evaluated in California.
    •  Spanish breeding programs have mastered late-bloom varieties and self-compatibility traits.
    • The Australian breeding program has some varieties that scored very high during Crack-Out Day and should be evaluated in California.
    • Several varieties created by the U.S. Department of Agriculture and UC breeding programs are performing quite well in ongoing trials in California.

    ‘Diversification is key’

    Breeding is an art of balancing improvements while accepting some trade-offs. To define this balance, experts must consider the various segments of the almond industry, starting with the growers, moving to the hullers and shellers, handlers, food companies and then, ultimately, the consumer. As Saa said, “Diversification is key.”

    “Different uses and different needs demand different varieties,” he explained. “When you think about an almond variety for snacking, for example, you think about crunch and strong flavor. But when you think about a variety for almond milk, you’re probably thinking about milder flavors. And if you’re looking for a variety to cover in chocolate, you’re looking for a short but round kernel shape.”

    Nonpareil and other soft-shell varieties dominate the snack segment because of their shape, smooth surface and light blonde color. Mission varieties like Marcona, Butte, Padre and Fritz typically are used for natural roasted and bulk purposes, as well as in candy and chocolate applications. And California varieties like Carmel, Monterey and Wood Colony often are roasted, salted and flavored. They also are good for slicing and slivering.

    Key varietal differences covered in the report include a summary of how many popular almonds grown in California are auto-incompatible, meaning they require cross-pollination between different varieties, and yet how some of the new varieties are self-compatible, requiring no cross-pollination. Another horticultural distinction covered in the report is crack-out percentage and double percentage. California varieties and some Australian varieties have a high crack-out percentage (kernel-to-shell ratio). In addition, the report discusses different varieties’ tendency to produce kernel “doubles,” and finally, maturity rate and its impact on harvest timing is also mentioned. Armed with this knowledge, said Saa, growers can be more flexible and have more operational diversification.

    “If you have only one variety that you need to harvest within a narrow window, you put a lot of demand on your resources at one critical point in time. However, when you have multiple varieties that you can harvest sequentially, you can leverage your equipment and maximize your resources,” Saa said. 

    Looking ahead to the future of breeding

    Creating new almond varieties is a slow and complex process. It can take as long as 15 years to develop a new breed and then another 10 to 15 years to truly test it.

    “Once you develop a variety, you need to see how it performs under differing weather and environmental conditions — and there’s only one harvest per year,” Saa said. “So in order to be confident in a new variety, we need to test during multiple harvests across the valley. Today, we’re trying to do that more efficiently than ever before.”

    To provide a mechanism to evaluate new varieties across the diverse almond-growing regions in the state, the Almond Board began funding long-term and multi-locational Regional Varietal Trials (RVTs) almost 50 years ago. The first trial ran from 1974-1981 and the second from 1993-2006.

    The current RVT – involving orchards in Butte, Stanislaus and Madera counties, all planted with 30 identical varieties – began in 2014. Saa expects the study to last until 2025. ABC coordinates with the UC’s research system on the RVT, and the UC provides important contributions from the leading plant nurseries and private breeders in the state.

    Saa said some important characteristics that researchers will evaluate in RVTs moving forward include:

    • a bloom period that begins no earlier than Nonpareil,
    • self-compatibility,
    • crack-out percentage equal to or more than 40%,
    • percentage of kernel “doubles” equal to or less than 10%, and 
    • increased yield potential.

    Growers interested in ABC’s RVT are encouraged to check out UC Davis’ Fruit & Nut Research & Information Center, as updated information from the ongoing RVT is expected to be published on the center’s website in early 2021.

  • Why Aren’t My Beans Drying Down?

    We cut our blackeye bean (cowpea) research plots at UC Davis almost 3 weeks ago and they’re still too green to harvest. If we tried now, the vines would get wrapped around the threshing cylinder.  Several growers in the Sacramento Valley have mentioned that their corn has sat at the same moisture level for weeks and is not drying down either, as one would normally expect for this time of year. But, nothing is normal this year!

    Why aren’t our crops drying down?

    Tragic fires throughout the West have pushed a lot of smoke and ash into the sky, creating fog-like conditions that reduce the intensity of the sun, shade crops, and lower temperatures. The blanket of smoke is like stepping into the shade under an awning on a 90oF day. This reduced sun intensity has affected the ability of crops to dry down in a timely manner. Increased humidity levels this past weeks haven’t helped either.

    While shading may be good for protecting tomatoes from sunburn with harvests running late due to COVID-related challenges, it is not good for drying down field crops.

    With the smoke finally dissipating, drying conditions are improving. We ended up turning our blackeye bean crop over to increase aeration and help it dry down.  Dry beans are sometimes turned to help dry the crop down, especially if they’re rained on, but the challenge is to be careful to prevent shattering.

    In corn, there aren’t any easy solutions.  One grower said their corn sat at 16.5% moisture for several weeks and finally they had to harvest it anyway. Dryers are available for drying corn and other crops to the proper storage moisture, but as we all know it’s expensive and with low grain prices this affects the bottom line.  — By Sarah Light & Rachael Freeman Long, UC Cooperative Extension

  • UC DAVIS AIR QUALITY EXPERT: AB 2959 MAY INCREASE GREENHOUSE GASES

    One of the state’s leading experts on the role of animal agriculture in climate change today urged legislators to oppose Assembly Bill 2959, legislation that would result in more food waste ending up in the state’s landfills.

    University of California, Davis Professor Dr. Frank Mitloehner, who has received awards from the United States Environmental Protection Agency (EPA) and the Distinguished Service Award for Outstanding Research – University of California Division of Agricultural and Natural Resources, says the legislation would have “devastating” impacts on farmers and the state’s goals to reduce greenhouse gas emissions.

    “If AB 2959 passes, the bill will take away a valuable opportunity to upcycle organic waste for animal feed and keep it out of the landfill, where it will release methane,” said Mitloehner, who is also director of the CLEAR Center at UC Davis. “We can’t throw blame at our farmers and producers for impacting warming, while taking away an opportunity for them to do their part.”

    According to Dr. Mitloehner, approximately 18 percent of materials that end up in landfills is wasted food. In the United States, about 30 to 40 percent of all food is wasted.

    Assembly Bill 2959 would allow municipalities to force restaurants, grocers and others with food waste to utilize large franchise haulers to dispose of their food waste. Currently, most of these establishments contract with smaller haulers that take food waste to farms for use as animal feed. The EPA’s food waste hierarchy cites this is a better use of food waste than turning it into compost or landfill disposal.

    The legislation is opposed by a broad coalition. It includes the California Restaurant Association, California Grocers Association, the California Retailers Association, the California Farm Bureau, Western United Dairies, the California Cattlemens Association and more than a dozen other groups.

    The bill is expected to be heard by the Senate Environmental Quality Committee, chaired by State Sen. Ben Allen (D-Santa Monica), within the next few weeks.

  • Study Finds 82 Percent of Avocado Oil Rancid or Mixed With Other Oils

    Consumer demand is rising for all things avocado, including oil made from the fruit. Avocado oil is a great source of vitamins, minerals and the type of fats associated with reducing the risk of heart disease, stroke and diabetes. But according to new research from food science experts at the University of California, Davis, the vast majority of avocado oil sold in the U.S. is of poor quality, mislabeled or adulterated with other oils.

    In the country’s first extensive study of commercial avocado oil quality and purity, UC Davis researchers report that at least 82 percent of test samples were either stale before expiration date or mixed with other oils. In three cases, bottles labeled as “pure” or “extra virgin” avocado oil contained near 100 percent soybean oil, an oil commonly used in processed foods that’s much less expensive to produce.

    “I was surprised some of the samples didn’t contain any avocado oil,” said Selina Wang, Cooperative Extension specialist in the Department of Food Science and Technology, who led the study recently published in the journal Food Control. “Most people who buy avocado oil are interested in the health benefits, as well as the mild, fresh flavor, and are willing to pay more for the product. But because there are no standards to determine if an avocado oil is of the quality and purity advertised, no one is regulating false or misleading labels. These findings highlight the urgent need for standards to protect consumers and establish a level playing field to support the continuing growth of the avocado oil industry.”

    Testing domestic and imported brands  

    Wang and Hilary Green, a Ph.D. candidate in Wang’s lab, analyzed various chemical parameters of 22 domestic and imported avocado oil samples, which included all the brands they could find in local stores and online. Wang and Green received a $25,000 grant from Dipasa USA, part of the Dipasa Group, a sesame-seed and avocado-oil processor and supplier based in Mexico.

    “In addition to testing commercial brands, we also bought avocados and extracted our own oil in the lab, so we would know, chemically, what pure avocado oil looks like,” Wang said.

    Test samples included oils of various prices, some labeled extra virgin or refined. Virgin oil is supposed to be extracted from fresh fruit using only mechanical means, and refined oil is processed with heat or chemicals to remove any flaws.

    Fifteen of the samples were oxidized before the expiration date. Oil loses its flavor and health benefits when it oxidizes, which happens over time and when exposed to too much light, heat or air. Six samples were mixed with large amounts of other oils, including sunflower, safflower and soybean oil.

    Only two brands produced samples that were pure and nonoxidized. Those were Chosen Foods and Marianne’s Avocado Oil, both refined avocado oils made in Mexico. Among the virgin grades, CalPure produced in California was pure and fresher than the other samples in the same grade.

    A push for standards

    Ensuring quality is important for consumers, retailers, producers and people throughout the avocado oil industry. Retailers want to sell quality products, shoppers want to get their money’s worth and honest producers want to keep fraudulent and low-quality oil out of the marketplace.

    But since avocado oil is relatively new on the scene, the Food and Drug Administration has not yet adopted “standards of identity,” which are basic food standards designed to protect consumers from being cheated by inferior products or confused by misleading labels. Over the last 80 years, the FDA has issued standards of identity for hundreds of products, like whiskey, chocolate, juices and mayonnaise. Without standards, the FDA has no means to regulate avocado oil quality and authenticity. 

    Avocado oil isn’t the only product without enforceable standards. Honey, spices and ground coffee are other common examples. Foods that fetch a higher price are especially ripe for manipulating, especially when adulterations can be too subtle to detect outside a lab.

    Wang is working to develop faster, better and cheaper chemical methods to detect adulteration so bulk buyers can test avocado oil before selling it. She is also evaluating more samples, performing shelf-life studies to see how time and storage affect quality, and encouraging FDA officials to establish reasonable standards for avocado oil.

    Wang has experience collaborating with industry and the FDA. Ten years ago, she analyzed the quality and purity of extra virgin olive oil and discovered that most of what was being sold in the U.S. was actually a much lower grade. Her research sparked a cascade of responses that led California to establish one of the world’s most stringent standards for different grades of olive oil. The FDA is working with importers and domestic producers to develop standards of identity for olive oil.

    “Consumers seeking the health benefits of avocado oil deserve to get what they think they are buying,” Wang said. “Working together with the industry, we can establish standards and make sure customers are getting high-quality, authentic avocado oil and the companies are competing on a level playing field.”

    Tips for consumers

    • The flavor of virgin avocado oil can differ by varieties and region. In general, authentic, fresh, virgin avocado oil tastes grassy, buttery and a little bit like mushrooms.
    • Virgin avocado oil should be green in color, whereas refined avocado oil is light yellow and almost clear due to pigments removed during refining.
    • Even good oil becomes rancid with time. It’s important to purchase a reasonable size that can be finished before the oil oxidizes. Store the oil away from light and heat. A cool, dark cabinet is a good choice, rather than next to the stove.  
    • How do you know if the oil is rancid? It starts to smell stale, sort of like play dough.
    • When possible, choose an oil that’s closest to the harvest/production time to ensure maximum freshness. The “best before date” is not always a reliable indicator of quality.

    – By Diane Nelson, UC Davis

  • Research Opp: Improving Our Understanding of Antibiotics in Dairy Farms

    Antibiotics play an essential role in maintaining animal health and productivity. To provide guidance and knowledge on antibiotic use and management practices, it is important to constantly update our understanding on the role of therapeutic antibiotic use and its impact on animal health. A veterinary project is being conducted by UC Davis to better understand antimicrobial resistance patterns in dairy calves, and we are looking for interested farms to participate in the study.

    The project will last around 1-2 months, with up to 2 people visiting the farm a few times a week to collect fecal samples and health data from animals. Any and all data generated will be made available to the owner/manager, and anyone entering the premises is willing to sign a waiver liability release if requested. Identity of participants will remain confidential. No photos will be taken on the facility without consent, and participants are free to back out of the study at any point, if they wish to do so.

    If interested and/or to obtain more information, please contact:
    Katie Lee (UCD, graduate student): lctlee@ucdavis.edu (408-239-9140) Rob Atwill (UCD, Professor): ratwill@ucdavis.edu (530-754-2154)