California Fruit and Vegetable

Tag: UC Davis

  • UC Davis Researchers Target Spotted-Wing Drosophila and its Threat Against California Berries

    Back in 2010, the UC Davis entomology labs of integrated pest management specialist Frank Zalom and molecular geneticist and physiologist Joanna Chiu  joined forces to target the spotted-wing drosophila (SWD), a serious threat to berry production in California.

    Drosophila suzukii, native to southeast Asia and first discovered in California in 2008, lays its eggs in such soft-skinned, ripening fruits as strawberries, raspberries, cherries, blueberries, peaches, nectarines, apricot and grape.

    It packs a powerful economic impact. The first year of its discovery in California, the economic loss amounted to $500 million. Latest statistics from 2015 indicate a $700 million national economic loss.

    The Zalom lab discovered the first SWD field populations with insecticide resistance in 2017. As the pest continues to spread throughout much of the country, anxious growers are worried about its increased resistance to pesticides.

    The team’s newly published research in Scientific Reports is the first to characterize the molecular mechanisms of insecticide resistance in D. suzukii and provide insights into how current management practices can be optimized.

    Lead author of the paper, “Transcriptome Analysis of Drosophila suzukii Reveals Molecular Mechanisms Conferring Pyrethroid and Spinosad Resistance,” is Christine Tabuloc, then a doctoral candidate and now a postdoctoral researcher working under the mentorship of Professors Chiu and Zalom.

    “In this work, we leveraged high throughput sequencing to identify biomarkers of insecticide resistance in D. suzukii,” Tabuloc explained. “We found that different genes are responsible for resistance to different chemicals. Specifically, we found that genes involved in metabolism are highly expressed in flies resistant to pyrethroid insecticides. We also observed evidence of two different mechanisms of resistance in 2 lines generated from a single spinosad-resistant population. We found an increased expression of metabolic genes in one line and increased expression of cuticular genes in the other.”

    “Therefore, we developed a diagnostic panel using these biomarker genes to differentiate between pyrethroid resistance and spinosad resistance,” Tabuloc related. “Not only can our assay now inform whether there is resistance, it can tell us which chemical the population is resistant to and how severe the resistance is. Additionally, this method is faster, enables for the testing of more populations, and is more comprehensive as compared to bioassays, the conventional way of testing for resistance.”

    Tabuloc added that “our work has enabled for the detection of resistance in California populations, and we are currently doing a nationwide screening to determine whether resistance is now present in other states. Currently, we are working with the Zalom lab to use the results of our assays to try and combat resistance. There are experiments in progress trying to increase the efficacy of insecticides by blocking some of the genes involved in resistance, such that the enzymes encoded by those genes have decreased function.”

    Zalom, a UC Davis distinguished professor emeritus who directed the UC Statewide Integrated Pest Management Program for 16 years, said he has been “working on spotted-wing drosophila with Dr. Chiu and her lab members since she joined the UC Davis faculty in 2010, and it has been an absolute pleasure.”

    Zalom, a past president of the 7000-member Entomological Society of America (ESA) and an elected Honorary Member, ESA’s highest honor, praised Chiu, a 2019-2024 Chancellor’s Fellow professor and now chair of the Department of Entomology and Nematology, as “one of the most collaborative researchers who I have ever worked with. When our lab found the first SWD field populations with insecticide resistance in 2017, it seemed obvious to ask Dr. Chiu about identifying the mechanism of resistance to different chemical classes and if it would be possible to develop a molecular diagnostic to confirm presence of  insecticide resistance in field populations without conducting the time consuming and labor-intensive bioassays that we were using.”

    “Dr. Chiu and her PhD student Christine Tabuloc took on this challenge and their work culminated in the description of genes associated with the resistance and the diagnostic assay presented in this paper,” Zalom said.

    The Zalom lab “selected the SWD isolines from California field populations displaying resistance to pyrethroids and spinosyns after conducting bioassays on many hundreds of SWD adults, then helped Dr. Tabuloc validate  results of the molecular assay,” he said.

    “This work not only represents good science; it has very practical implications,” Zalom said. “Dr. Tabuloc and I presented results of the work from both of our labs at a special berry grower seminar on insecticide resistance organized by UC Agriculture and Natural Resources (UC ANR) Farm Advisor Mark Bolda in Watsonville. The presentations were extremely well-received. The original program was targeted for about 1.5 hours, but the meeting extended to over three hours due to the extent of questions and great discussion that followed. Growers and their consultants are hungry for new information that they find interesting and potentially useful, and this work was clearly of interest to them.”

    Bolda, strawberry and caneberry farm advisor in Santa Cruz, Monterey and San Benito counties, “was the first person who found the insect and asked me to come down to look at it and the problem,” Zalom remembered. “That was 2008, and we weren’t able to get an actual species identification until 2009!”

    Bolda noted that the recent berry grower meeting targeted SWD resistance on the Central Coast, with the UC Davis entomologists presenting. “The research was top shelf and the need, of course, is very great,” Bolda said. “Some of the information that Frank and Christine presented has been put into immediate use in the industry.”

    “What made it really special was that since we were moving only a month or so later, and this was the last Extension meeting to be held at my UC Cooperative Extension Office,” Bolda said. “After 40 some years, that’s saying a lot and it was totally apropros that Frank, given his many, many years of service, was the very last to run a meeting there….and Christine presented also…she was really great and presented fabulous information.”

    Among the “iconic individuals of Central Coast strawberries” who attended, Bolda said, was retired entomologist Ed Show (Driscoll Strawberry Association, Inc.) “who has been a part of strawberries since the 1970s.”

    “It was nostalgic for me since it was the last meeting that was held there because they were moving to a new office,” Zalom said. “I must have done 80 presentations at that auditorium over the years, including some of the very first ones that I did when returning to California when I was doing research on brussels sprouts and apples in that area.”

    Fruitville Collaboration. Professor Chiu said the publication “culminated years of fruitful collaboration and hard work by our lab and Professor Zalom’s lab, primarily driven by Christine…This research could not have been accomplished without Christine who is uniquely qualified to successfully lead the project; she combines her knowledge in insect genomics and bioinformatics with Drosophila molecular genetics.”

    Chiu pointed out that “When the Zalom lab and my lab first started our collaboration in 2010, we were already worried about the potential development of insecticide resistance in D. suzukii given the primary method for management is insecticide application and the generation time of these flies are short. Unfortunately, this became a reality in 2017.”

    “We hope that our research in developing more efficient molecular diagnostics to identify resistant populations will help prevent the spread of resistance to other U.S. states by allowing them to be proactive; perhaps to adjust their management program as soon as low level of resistance is detected,” Chiu said. “We are continuing to perform research to determine if resistance, once found, can be ‘weakened’ and what are mechanisms that could drive it. We think this will be very beneficial for growers in California, who currently have to tackle D. suzukiiwith insecticide resistance.”

    Tabuloc, who joined the Chiu lab as an undergraduate research assistant in 2012, received her bachelor of science degree in biochemistry and molecular biology from UC Davis in 2015, and her doctorate from UC Davis in 2023.

    In addition to Chiu, Zalom and Tabuloc, the 12-member team of researchers and co-authors included Curtis Carlson, Kyle Lewald, Sergio Hidalgo, Cindy Truong and Ching-Hsuan Chen, all from the Chiu lab; Nicole Nicola and Fatemeh Ganjisaffar of the Zalom lab; and Cera Jones and Ashfaq Sial of the Department of Entomology, University of Georgia, Athens. At the time, Truong and Chen were undergraduates, and Ganjisaffar was a postdoctoral fellow, and now a senior environmental scientist with the California Department of Food and Agriculture.

    Federal and state grants awarded to Chiu and Zalom funded the project: a USDA National Institute of Food and Agriculture; and a California Department of Food and Agriculture Specialty Crop Block Grant. The team credits Bloomington Drosophila Stock Center for providing D. melanogaster stocks.

  • UC ANR Publishes First-Ever Olive Production for Oil Manual

    Facing a deluge of lower-price products from Europe, the California olive oil industry is doubling down on its clear-cut competitive edge: the consistent and bona fide quality of its oil.

    “Olive Production Manual for Oil,” a new book published by University of California Agriculture and Natural Resources, aims to help California olive growers maximize that advantage.

    “It’s a tough market to compete in, but I think the way to win for California is to compete on quality,” said book co-editor Selina Wang, a UC Cooperative Extension specialist in the UC Davis Department of Food Science and Technology. “The quality of California olive oil is unmatched, but you can’t make good quality olive oil with bad fruit, so the goal is to get more fruit from the trees – and for the fruits to be high-quality fruit.”

    The 273-page manual, available for purchase online, is the first of its kind in the U.S. While some parts of the book are specific to California (which grows nearly all of the olives for domestically produced olive oil), most of the material would be useful to producers in other states, Wang noted.

    “Through our conversations with growers, it became clear to us that a manual like this – not a scientific publication but a manual that is easy to follow, written in language that is accessible, and with pictures and illustrations – would be really helpful to the growers,” she said.

    Growth of California olive oil industry necessitated creation of manual

    The new oil olive production manual, published by UC ANR, is the first of its kind in the U.S. Copyright UC Regents

    Aside from a book focused predominantly on table olives and another on organic olive production (by UCCE farm advisor emeritus Paul Vossen), there was no one-stop, comprehensive resource on the bookshelf for oil olive growers. The need for such a manual had become more acute as oil olives replaced table olives in California orchards during the last 20 years.

    Whereas harvesting by hand was historically cost-prohibitive, the introduction of super-high-density planting systems in 1999 made oil olive production more economically feasible. Mechanical pruning and harvesting of new cultivars (Arbequina, Arbosana and Koroneiki) – specifically bred for these densely planted orchards – led to the rapid expansion of oil olives in the state. According to a U.S. Department of Agriculture report, California olive oil production jumped from 2 million pounds in 2006 to an average of 21 million pounds in 2021–23.

    With about 37,000 acres of oil olives planted across California, the Olive Oil Commission of California saw the need to support the production of this manual. Championed by Dan Flynn, founder and executive director emeritus of the UC Davis Olive Center, Wang and co-editor Louise Fergusonoutlined the contents of the book. They then sought out a mix of growers and industry professionals and UCCE advisors and specialists to write its chapters.

    “Most of the information is data-based, from people who are working with the olives,” said Ferguson, a UC Cooperative Extension pomologist at UC Davis. “This is the first data-based olive oil production manual we’ve had.”

    Manual infused with firsthand insights, practical recommendations

    Of the three main varieties planted in super-high-density systems, Arbosana has the most consistent fruit yield. Photo by Dan Flynn; copyright UC Regents

    Hard-earned experience taught growers a valuable lesson that is conveyed in the book – the need to hand-prune. While mechanical pruning helps control the size of the trees, some hand-pruning is still required to allow light to filter to the leaves. Failing to do so leads to a dramatic decrease in yield.

    “That happened in many of the orchards that were inexperienced in these new cultivars and new super-high-density planting systems,” Ferguson said.

    She added that other key topics in the manual include irrigation management in a water-constrained state, nitrogen management, harvest timing and orchard site selection. Choosing a good spot for planting is crucial in this era of extreme climate volatility, Ferguson noted, as olive trees are significantly affected by temperature shocks in spring (fruit set) and fall (harvest).

    For Wang, another overarching theme in the manual is the importance of testing. Testing the soil, water and leaves provides critical data that growers can use to adjust their inputs and production practices for optimal profitability.

    “You may spend a couple hundred dollars on the lab work, but it will pay off, for sure – you’re going to increase the health and productivity of your trees,” Wang explained. “Oil olive growers are paid based on the oil content in their fruit; you not only want to have a lot of fruit on the trees, you want to make sure that your fruit are accumulating oil.”

    California oil olive growers, practices continue to evolve

    Wang and Ferguson hope their book will help California producers compete more effectively in the global marketplace. Currently, about 90% of the olive oil consumed in the U.S. is imported from Mediterranean countries, due primarily to the lower price point. In that region, producers tend to harvest riper olives that produce oil at a greater volume but lesser quality.

    In contrast, California growers harvest earlier and produce oil that is higher quality (with more flavor and more antioxidants) and far exceeds accepted standards for “extra virgin olive oil.”

    According to Wang, California olive oil mills have nearly maximized their efficiency, and the growth opportunity for the industry is in the orchards: to optimize practices to produce more fruit, and to plant more trees. Wang said the new manual can help on both fronts.

    “Just like for other crops, focusing on quality – while increasing efficiency and productivity, and therefore profitability – is the name of the game,” she said.

    Ferguson also stressed that knowledge continues to evolve and urged growers to reach out to the editors and chapter authors with their experiences.

    “Most of the authors are in California and they’re working,” she said. “So if you start to notice things that are different, or you want more information or something is not clear, the authors are available.”

    The manual can be purchased at https://anrcatalog.ucanr.edu/Details.aspx?itemNo=3559. — By Michael Hsu, UCANR

  • Biological Control Considerations and Research for Lettuce Growers

    Two of the worst pests plaguing lettuce growers in the Salinas Valley area are aphids, specifically lettuce-currant aphids (Nasovonia ribisnigri), and western flower thrips (Frankliniella occidentalis). Lettuce-currant aphid is an invasive pest that sets up shop in the heart of the lettuce plant and will render the crop unsellable when it reaches high enough numbers. Thrips can both cause cosmetic damage to lettuce crops and are also responsible for the spread of Salinas impatiens necrotic spot virus (INSV), the fatal lettuce disease that has driven large losses since the 2020 growing season.

    While effective tools exist to control both aphids and thrips, they are almost exclusively chemical. Chemical sprays are increasingly under pressure due to changes in the regulatory framework in California as well as the development of pest resistance and discoveries of key chemistries in area watersheds1,2. The UC Davis FiVE lab biological control research program addresses a growing interest in developing alternative tools for managing both pests that do not rely on chemical applications. Biological control provides an opportunity for the management of thrips and aphids that do not rely on chemical tools.

    Biological control is defined as the use of natural enemies to control a target pest. Three general categories of biological control could possibly be used as management practices for lettuce pests in the Salinas Valley area:

    • Conservation biological control refers to the establishment and maintenance of resources and conditions favorable to a native or endemic beneficial species. Instead of releasing predators into crop fields, specific types of flowers and other habitats are planted to attract beneficial species that are already a part of the local ecosystem. To date, most efforts on biological control in lettuce have used the conservation biological control approach.

    • Inundative biological control involves the release of a beneficial insect species in large numbers with the expectation that the beneficials that are released will only provide control for a short amount of time before eventually dying out. Such releases would need to be repeated at regular intervals for the duration of the growing cycle for a crop.

    • Augmentative biological control refers to the use of releases of smaller numbers of beneficials to areas where a smaller population of the species already exists, but not in numbers great enough to provide adequate control of the targeted pest species. The goal of augmentative releases is to bolster already-existent populations of beneficial species so they achieve great enough numbers to provide control of the pest or pests of interest.

    Conservation biological control in the Salinas Valley

    Syrphid flies

    Aphid pests of lettuce have been effectively managed in some lettuce production systems through the planting of sweet alyssum adjacent to and interspersed within crop fields3. Sweet alyssum is a favorite of the Syrphid fly (Diptera: Syrphidae), the primary biological control agent used to control aphid pests in lettuce. Syrphids, also called hoverflies or flower flies, are a family of black and yellow pigmented flies which resemble bees and stinging wasps. The coloration is a protective camouflage; Syrphid flies are harmless to humans. Syrphid adults are frequently seen visiting flowers for their nectar and pollen, which the insect consumes both as an energy source and to support their reproduction.

    In exchange the female Syrphid flies will lay eggs in lettuce plants with lettuce aphid infestations, the primary food source for their young. Once the eggs hatch, the syrphid maggots, which are predatory on slow, soft-bodied insects, will feed on the aphids and suppress their population. Syrphid larvae are known to be voracious; some California species have been shown to consume upwards of 100 aphids per day4!

    Syrphids are the intended beneficiaries of most conservation biological control in central coast lettuce fields, but other beneficial species take advantage of these resources as well.

    Other predatory species love sweet alyssum

    Many other biological control agents are supported by insectary plantings5. Ladybird beetles often inhabit lettuce fields and may provide some control of lettuce aphid infestations. Common lacewings (family Chrysopidae) are also found in lettuce fields and insectary plantings. Lacewings, which are only predatory in their immature or larval life stage, can provide biological control services against lettuce aphids and western flower thrips. Minute pirate bug (Orius sp.) and aphid midges (Aphidoletes aphidimyza) have also been observed in and collected from insectary plantings in lettuce fields, but it is not known the extent to which they can suppress populations of lettuce aphid or Western flower thrips.

     UC Davis Fi-VE Bug IPM Lab biological control research programs

    Including insectary plantings to attract naturally occurring predators has historically been the only efficient way to get beneficial species into crop fields. Newly developed technology using drones as a dispersal tool may provide another option for growers interested in using biological control as part of their pest management programs for aphids and thrips. This technology drastically reduces the time and labor required to conduct large releases of laboratory-reared beneficial insects, making the approach more feasible for growers.

    As part of a research program funded by the California Department of Pesticide Regulation (CA DPR) and in collaboration with Daniel Hasegawa at USDA-ARS and with Parabug, we are studying the release of biological control agents using drones for the management of aphid and thrips pests of lettuce crops. Our three experimental programs are as follows:

    In-field inundative releases of green lacewing larvae and predatory cucumeris mites to control aphids and thrips in lettuce

    In-field drone release of green lacewing eggs and predatory mites

    Experiments run by former Monterey County IPM Advisor Alejandro Del Pozo-Valdivia found that a single inundative release of green lacewing eggs (Chrysoperla rufilabris) in lettuce fields reduced aphid pressure six weeks after release6. Our experiment builds on Alejandro’s work, examining whether repeated releases of green lacewing eggs throughout the lettuce growing cycle reduce aphid numbers. Additionally, the experiment includes two treatments aimed at suppressing western flower thrips: inundative releases of a species of predatory mite (Amblyseius cucumeris), and a combined release of both predatory mites and green lacewing eggs.

    Augmentative releases to bolster non-syrphid predatory species in insectary strips and intercropped alyssum

    An insectary strip treated with an augmentative release of Orius insidious

    Other native predators of aphids and thrips are present in the insectary plantings growers use to attract syrphids, but their numbers are too low to provide suppression of thrips and aphids in adjacent crops. These species are reared by commercial insectaries, but using them in an inundative release could prove too costly for growers. Experiments in this program examine the use of smaller releases of these predatory species early in the growing cycle over insectary plantings. The goal is to determine whether the presence of floral resources allows the predators to stick around and build up enough in population to control aphids and thrips in the crop field. Experiments will be conducted with aphid midge (Aphidoletes aphidimyza), an aphid predator, and minute pirate bug (Orius insidiosus), a predator of western flower thrips.

    Augmentative releases to manage thrips in non-crop areas

    Drone release of thrips predators over ice plant

    Western flower thrips plague not just vegetable crop fields but also the vegetation surrounding crop areas. In this experiment, we will examine whether releases of cucumeris mites and minute pirate bugs over field edges planted with ice plant will establish these predators in the vegetation and provide long-term suppression of western flower thrips. — By Ian Grettenberger and Addie Abrams, UC Cooperative Extension

    Citations

    1. Deng, X. Study 321: Surface water monitoring for pesticides in agricultural areas in the Central Coast and southern California (2022)
    2. Gao, Y., Lei, Z. & Reitz, S. R. Western flower thrips resistance to insecticides: detection, mechanisms and management strategies. Pest Manag. Sci. 68, 1111–1121 (2012).
    3. Brennan, E. B. Agronomic aspects of strip intercropping lettuce with alyssum for biological control of aphids. Biol. Control 65, 302–311 (2013).
    4. Hopper, J. V., Nelson, E. H., Daane, K. M. & Mills, N. J. Growth, development and consumption by four syrphid species associated with the lettuce aphid, Nasonovia ribisnigri, in California. Biol. Control 58, 271–276 (2011).
    5. Bugg, R. L., Colfer, R. G., Chaney, W. E., Smith, H. A. & Cannon, J. Flower Flies (Syrphidae) and Other Biological Control Agents for Aphids in Vegetable Crops. (University of California, Agriculture and Natural Resources, 2008). doi:10.3733/ucanr.8285.
    6. Del Pozo-Valdivia, A. I., Morgan, E. & Bennett, C. In-Field Evaluation of Drone-Released Lacewings for Aphid Control in California Organic Lettuce. J. Econ. Entomol. 114, 1882–1888 (2021).

  • International Olive Symposium Coming to UC Davis

    The IX International Olive Symposium grants a golden opportunity for researchers and industry stakeholders to once again share research findings and industry development, at the University of California, Davis, September 10-14th. This is not an annual event, so take advantage of this rare occasion and visit some of the best places that California has to offer!

    This 5-day Symposium, hosted by ISHS, will include all aspects of basic and applied research, including: and will include all aspects of basic and applied research, including: breeding & genetics, crop physiology & biology, orchard design, propagation, planting systems, canopy management, soil management, crop protection, harvest, irrigation & fertilization, climate change and sustainable orchard management, precision management and new technologies, table olive & olive oil processing, quality and safety, olive oil health benefits, adulteration, by-products, marketing including, economics, certification and rural policy.  For more information and to register to attend, click HERE.

  • Nearly 70% of Private Label Avocado Oil Rancid or Mixed With Other Oils

    Avocado oil has become a popular choice for many people in recent years because of its heart-healthy benefits and versatility in cooking. However, not all avocado oil products on store shelves are created equal. Some products are labeled as “pure” avocado oil when they contain other oils or additives. No enforceable standards defining the chemical and physical characteristics of avocado oil exist yet.

    Researchers at the University of California, Davis, analyzed samples of 36 private label avocado oil products and graded them based on quality and purity. Private label products are made by a third-party processor and sold under a grocery store or retailer brand label. Their findings, published in the journal Food Control, show that 31% of the samples tested were pure, and 36% were of advertised quality. Quality refers to whether the oil is fresh or has gone bad due to aging, heat or light exposure. For purity, researchers measured fatty acids, sterols and other components that differentiate avocado oil from other oils.

    The study included oils purchased from 19 retailers in the U.S. and Canada with various price points. They found that lower-priced oils were more likely to be tainted with other oils.

    “We found that low-cost products indicate a higher probability for adulteration, but high cost didn’t guarantee purity or quality,” said Selina Wang, associate professor of Cooperative Extension in the Department of Food Science and Technology. She and Hilary Green, a postdoctoral researcher at UC Davis, co-authored the paper.

    Researchers also identified certain chemical markers in avocado oil that professional retail buyers can use to make more informed decisions when it comes to choosing suppliers. This way, consumers can feel confident about the products they buy.

    This is the second comprehensive study conducted by UC Davis researchers on the quality of avocado oil sold in the U.S. The first study released in 2020 found that many of the test samples were of poor quality, mislabeled or adulterated with other oils.

    “This study demonstrates that although progress is being made in standard development since our first market study in 2020, there are still issues with purity in avocado oil and these issues extend significantly into private label oils,” Wang said.

    Avocado oil standards

    Since the release of the first UC Davis study, Wang said there’s been a coordinated effort by researchers, industry leaders and government agencies to establish enforceable standards. The Avocado Oil Expert Group was formed in collaboration with the American Oil Chemists’ Society to discuss potential standards and future research projects.

    Wang’s research group has been studying how natural factors like different types of avocados, harvest times, geographic origins and processing methods could affect the chemical composition of avocado oil. They want to create standards that will accommodate natural variations while detecting any adulterations.

    Wang hopes that the study’s findings will contribute to the establishment of standards that benefit both consumers and avocado oil producers who want to compete in a fair market.

    “I’m very optimistic for the future of the avocado oil industry,” Wang said. “It’s a high-value product with high consumer demand, similar to what I saw with olive oil 10 years ago. Olive oil quality and purity have improved significantly, which is where I see avocado oil going, if we can establish fair standards and eliminate fraudulent products.” — By Tiffany Dobbyn, UC Davis

  • Thirteen UC Davis Scientists Contribute to Special Journal Edition on Spotted-Wing Drosophila

    Thirteen UC Davis scientists or former affiliates are among authors from eight countries who contributed to research articles for the Journal of Economic Entomology’s Special Collection: Research Advances in Spotted-Wing Drosophila suzukii Management.

    The recently published Special Collection showcases 14 articles.

    Native to Asia, the agricultural pest is a worldwide threat to the berry production industry, which includes raspberries, blackberries, blueberries, strawberries, and cherries. The tiny insect, about 1/12 to 1/8 inch long, invaded the continental United States in 2008.

    “All of the papers were by invitation of the co-editors of the special collection—Jana Lee, Cesar Rodrigue-Saona, and me,” said journal editor-in-chief Frank Zalom, a UC Davis distinguished professor emeritus and recall professor in the Department of Entomology and Nematology. Zalom’s research includes the spotted-wing drosophila.

    Lee, formerly with the UC Davis laboratory of the late chemical ecologist Steve Seybold, is a research entomologist with the Horticultural Crops Research Unit,  U. S. Department of Agriculture, Agricultural Research Service, Corvallis. Rodriguez-Saona, who received his doctorate from UC Riverside, is an Extension entomologist with the Department of Entomology, Rutgers University, the State University of New Jersey.

    In addition to Zalom and Lee, the UC Davis-linked authors include Joanna Chiu and Antoine Abrieux (Joanna Chiu lab); Zain Syed and Kevin Cloonan (Walter Leal lab); Gregory Loeb (Rick Karban lab); and Kelly Hamby, Hannah Burrack, Fatemeh Ganjisaffar, Brian Gress, Nicole Nicola and Mark Demkovich (Zalom lab).

    Overall, the Special Collection includes authors from Austria, Brazil, Canada, Italy, Spain, Sweden, United Kingdom, and the United States that represent perspectives from universities, federal and state laboratories, growers, and pest product companies, according to the editors.

    One paper, Spatio-temporal Variation of Spinosad Susceptibility in Drosophila suzukii (Diptera: Drosophilidae), a Three-year Study in California’s Monterey Bay Region, is from the Zalom lab and includes co-author, molecular geneticist and physiologist Joanna Chiu, professor and vice chair of the Department of Entomology and Nematology.

    The work of molecular geneticist and physiologist Joanna Chiu, professor and vice chair of the UC Davis Department of Entomology and Nematology, is included in the Journal of Economic Entomology’s special collection targeting research on the spotted-wing drosophila. (Photo by Kathy Keatley Garvey)

    UC Davis Department of Entomology and Nematology communication specialist Kathy Keatley Garvey provided the cover photo of the spotted-wing drosophila feeding on a raspberry.

    Since 2008, “D. suzukii has become a key economical pest of raspberries, blackberries, blueberries, strawberries, and cherries in the United States and worldwide,” the editors wrote in their introductory remarks. “Not surprisingly, the number of publications has proliferated from 29 publications as of 2010 to 978 additional publications between 2011 and 2021 from a Web of Science search for ‘Drosophila suzukii.’ While many publications are available, this special collection will highlight advances in D. suzukii pest management since its U.S. invasion. We solicited papers by open call and received 66 abstracts, and selected 14 papers covering: 1) review, 2) monitoring and risk, 3) behavioral control, 4) biological control, 5) cultural control, and 6) chemical control.”

    The collection is meant to serve “as a key reference point for entomologists across many institutions (e.g., academia, government, and industry) on important advances in D. suzukii pest management,” according to the Entomological Society of America. “The articles in this collection will also provide scientists information on potential research gaps that will help guide future research directions on this important pest. The goal is to preserve and catalog articles on various aspects of D. suzukii pest management, i.e., monitoring, cultural control, chemical control, behavioral control, and biological control, that will be shared among entomologists.”

  • Field Bindweed Yield Impacts on Processing Tomatoes May be Less than Expected

    Figure 1. Field bindweed (Convolvulsus arvensis)

    Field bindweed (Convolvulsus arvensis) is considered by many tomato growers to be the most problematic of all weeds in California production areas. Indeed, field bindweed and the closely related morning glory weeds were ranked the 8th most troublesome weeds in North America in a recent survey by the Weed Science Society of America. The rapid adoption of drip irrigation and the economic necessity of maintaining the beds and replanting with only minimal tillage for multiple seasons in processing tomatoes has created a system where field bindweed has become more prevalent. Field bindweed is extremely difficult to control because it propagates from seed and vegetatively from buds formed in the roots. Seedlings can be controlled with tillage when very young, but they become perennial very rapidly. Chemical control of seedlings is possible, but established plants are much more difficult to control. Established plants often have a large root system relative to the amount of top growth, and thus are extremely tolerant of post emergence herbicides such as carfentrazone (Shark), glufosinate (Rely), and glyphosate (Roundup).

    Bindweed is a headache not only for its persistent and pernicious growth habit and ability to reduce tomato yields, but also because it can physically stop a processing tomato harvester in the field. Vigorously growing vines can become entangled around the shaker and conveyor belts, requiring the equipment operator to shut down and manually clear out the foliage.

    Several years ago, myself and other UC researchers conducted herbicide trials evaluating field bindweed control — with marginal success. In a given year and location, most of the registered herbicides in tomatoes gave only temporary suppression – about 40 – 80% bindweed control at 8 weeks after transplanting. Best results were observed where herbicides were stacked: trifluralin (Treflan) pre-plant incorporated followed by rimsulfuron (Matrix) post. Glyphosate helped in situations where the bindweed emerged early and could be applied before transplanting (Figure 2).

    Figure 2. Bindweed control plots at UC Davis. Untreated control on the left, glyphosate, trifluralin, and rimsulfuron on the right.

    Earlier this year, I was asked to summarize the effects of weeds on processing tomato yield. This made me go back and look at this work, but with a slightly different emphasis: impact of weed control (or really, lack of weed control) on yield. To increase the size of my dataset, I also included data from trials done at UC Davis. Where I had data for both yield and weed control in good, replicated trials, I performed a regression analysis comparing % weed control and % relative yield (relative yields remove the year-to-year and location variability). In the end, I used 4 trials from 2012-13 (Table 1).

    Scott Stoddard, UC Cooperative Extension Merced-Madera Counties Vegetable Crops and Soils Farm Advisor

    Surprisingly, these data suggested that where bindweed dominated, it did not have a big impact on processing tomato yield. Even with just 50% control 8 weeks after transplanting, potential yield was 88-95%. This may have occurred because bindweed does not shade out the tomato canopy nearly as much as some of the common annual weeds. However, when tall broadleaf weeds dominated, such as pigweed, nightshades, and lambsquarters, yields dropped rapidly. I had some plots with a 99% yield drop if these weeds were allowed to grow all season. In this situation, the weeds towered over the tomato canopy.

    There have been no new registered herbicides in processing tomatoes in the last 10 years, while robotic weed control has progressed rapidly during this time. Unfortunately, neither our current slate of registered herbicides nor robots provide adequate control of field bindweed. This may not matter as much as previously thought, however. The annual grasses and broadleaf weeds have far greater yield impact, especially when they grow tall and shade out the crop. Thankfully, there are several registered herbicides that provide effective control of those weed types. — By Scott Stoddard, UC Cooperative Extension

  • Dan Flynn Receives the 2020 California Olive Oil Council Pioneer Award

    The 2020 recipient of the California Olive Oil Council (COOC) Pioneer Award has made a lasting impact on the California olive oil industry. Dan Flynn started the UC Davis Olive Center 13 years ago where he serves as the executive director with just $50,000 from university and industry supporters, and grew it into a world-renowned center for olive research and education. The organization has worked in concert with the California Olive Oil Council from its beginning in 2008. In partnership with the industry, UC Davis has helped millions of consumers understand the quality of supermarket olive oil, provided the analytical foundation for California’s strict olive oil standards and educated thousands to become better olive growers, processors and tasters.

    If the success of a leader can be measured by the fingerprints they leave behind, Dan’s impact on the olive oil industry should not be understated, said David Garci Aguirre, Vice President of Operations for California-based premium olive oil producer Corto. “Several of the most influential events in the industry over the last decade are the direct result of the work completed by Dan and his team at the UC Davis Olive Center.”

    Flynn’s attributes much of the center’s success to creating partnerships between dozens of academic specialists, olive growers and processors. He has worked tirelessly to nurture the network which has resulted in priceless value. Flynn focused on serving the industry while meeting the needs of UC Davis. The partnership between UC Davis and California agriculture has delivered enormous benefits for the California olive crop.

    Flynn has also built relationships with international researchers to leverage their research for the benefit of California. The international conferences with the Culinary Institute of American and the International Olive Council have elevated the California industry on the global stage. He has positioned the UC Davis Olive Center as an independent and trusted facilitator where everyone is welcome.

    “Dan Flynn deserves our recognition, praise and applause. He pioneered making the Olive Center a reality where the millers, growers, and producers have ready access to the research and learning tools needed for the Crop of The Future,” said Karen Bond, Owner of Bondolio Olive Oil.

    Flynn is preparing to retire in June. His successor, Javier Fernandez-Salavador, will inherit a strong Olive Center, guided by a 10-year strategic plan to bolster research, funding and connectivity. “I will still be active in helping the center and I will always be grateful for the support of the COOC and its members,” said Flynn.

    The Pioneer Award was established in 1999 to recognize those who have made a major contribution to the California olive oil industry and the COOC. “The COOC thanks Dan for his commitment, partnership and support over the years, and wishes him all the best in the future,” said Patricia King, Executive Director of the California Olive Oil Council.

  • Will California Remain Leader in U.S. Ag Production?

    A new book shows how California has led the nation in farm sales since 1948 and explores future challenges

    “California Agriculture: Dimensions and Issues” by the Giannini Foundation of Agricultural Economics details the past, present and future of many of California’s major agricultural commodities, including grapes, tree fruits and nuts, vegetable crops, dairy, livestock, nursery and floral production, and cannabis. The new 18-chapter book, written by agricultural economists at UC Davis, UC Berkeley and UC Riverside, addresses issues such as labor, water, climate and trade that affect all of California agriculture.

    “California agriculture overcame many obstacles to become the nation’s number one farm state. Leading agricultural economists are generally optimistic that California agriculture will continue to thrive in the 21st century, despite continuing large challenges,” said Philip Martin, UC Davis emeritus professor of agricultural and resource economics, who is co-editor of the new publication.

    For over 70 years, California has led the nation in farm sales due to its specialization in high-value commodities such as fruits, nuts, vegetables and other horticultural crops. The book uses the most recent Census of Agriculture data to show that, of the $64 billion of these crops produced in the U.S. in 2017, California produced nearly half by value ($31 billion).

    In 1879, wheat and barley occupied over 75% of the state’s cropland. The types of crops grown in California have changed considerably over the years.

    More than 44 percent of California’s $50 billion in farm sales in 2017 were fruits and nuts, with 17 percent of sales from vegetables and melons, and 14 percent from nursery and other horticultural specialties crops. Many of these high-value specialty crops are also very labor-intensive and face challenges from increased cost and decreased availability of agricultural labor. The book discusses how California growers effectively responded to these labor challenges by adopting labor-saving mechanization. California remains competitive with producers elsewhere by relying on superior plant varieties, integrated pest management, and improved irrigation methods that increase both the quantity and quality of California agricultural commodities.

    Water, climate and trade pose challenges and opportunities for California agriculture. In the last decade, water scarcity and decreased water quality, along with regulations to address these issues like the Sustainable Groundwater Management Act, have prompted farmers to use scarce water to irrigate more valuable crops, as with the switch from cotton to almonds. Increased regulations and the increasing scarcity of water affect high-value specialty crops as well as the dairy and livestock industries that accounted for 24% of California farm sales in 2017.

    Climate variability, including drought and heat stress, affects farmworker welfare, crop yields and dairy productivity. Retaliatory tariffs resulting from the 2018 trade war reduced U.S. agricultural exports to China by close to $14.4 billion per year, as exports of dairy, livestock and specialty crops fell.

    California agriculture has a rich history of overcoming challenges by pursuing innovative research, adopting new technologies, and adapting to changing conditions. Learning how California agriculture has succeeded in the past suggests that the state can maintain its dominant role as an agricultural producer in the future.

    Learn more about several of the major California agricultural commodities and the issues and opportunities they face in this new, second edition of California Agriculture: Dimensions and Issues. Read the book for free online as part of the Giannini Foundation’s Information Series (20-01) at https://giannini.ucop.edu/publications/cal-ag-book/. A paperback copy of the 414-page book can be ordered for $55 at http://bit.ly/CalAgBook2ndEd. – By Ria DeBiase, Communications Director, Giannini Foundation of Agricultural Economics

    The Giannini Foundation was founded in 1930 from a grant made by the Bancitaly Corporation (later renamed Bank of America) to the University of California. Its mission is to promote and support research and outreach activities in agricultural economics and rural development to benefit the agricultural industry, policymakers, and society at large. Giannini members include University of California faculty and Cooperative Extension Specialists in agricultural and resource economics. Learn more about the Giannini Foundation of Agricultural Economics at https://giannini.ucop.edu.

  • UC Partners with Gotham Greens to Advance Indoor Ag

    Gotham Greens, a pioneer in indoor agriculture operating high-tech greenhouses across the United States, is placing its latest state-of-the-art greenhouse near UC Davis.

    “We are building a Controlled Environment Agriculture Consortium to support and advance the indoor farming industry, grow more fresh produce on less land and create new jobs for Californians,” said Gabriel Youtsey, UC ANR chief innovation officer. “Gotham Greens is an anchoring partner of this research and industry collaboration that we hope will spur innovation, create a new indoor farming workforce and support industry growth.”

    University of California Agriculture and Natural Resources and the UC Davis College of Agricultural and Environmental Sciences have entered into a partnership with Gotham Greens to advance research and innovation in the areas of indoor agriculture, advanced greenhouse technology and urban agriculture. The new greenhouse facility enables opportunities for Gotham Greens and the University of California system to collaborate on research and innovation focused on advancing the science, workforce, technology and profitability of indoor agriculture globally.

    “We are proud to bring Gotham Greens to the West Coast and partner with one of the highest ranked agricultural research centers in the world to advance the entire agriculture system,” said Viraj Puri, Gotham Greens co-founder and CEO. “California is responsible for growing one-third of the country’s vegetables and two-thirds of the nation’s fruits, yet in recent years, issues surrounding drought, food safety and worker welfare have demonstrated the need for continued innovation. Gotham Greens offers consumers clean, safe and sustainably grown leafy greens, herbs and versatile, time-saving plant-based dressings, dips and cooking sauces.”

    Located in Solano County, the first phase of Gotham Greens’ 10-acre greenhouse facility is expected to open in 2021 and will enable the company to deliver fresh, greenhouse-grown leafy greens to more retailers, foodservice operators and consumers on the West Coast. The company operates one of the largest and most advanced networks of hydroponic greenhouses in North America, where the demand for indoor-grown produce continues to surge. Nearly a decade after launching the nation’s first commercial-scale rooftop greenhouse, Gotham Greens continues to reimagine how and where fresh produce is grown across America.

    “We’re excited about collaborating with Gotham Greens, which is a coveted employer for tomorrow’s leaders in agriculture and engineering,” said Helene Dillard, UCD CAES dean. “This partnership will offer our students the chance to learn best practices from leading experts in indoor farming.”

    The greenhouse will generate 60 full-time jobs and provide students in the University of California system with an opportunity to learn firsthand from the industry leader. Gotham Greens recently raised $87 million in new equity and debt capital, bringing the fast-growing company’s total financing to $130 million and fueling its next phase of growth.

    “We are delighted for Gotham Greens to join Solano County’s thriving agricultural economy and help to usher in a new era in farming innovation, job creation and economic growth for the region,” said Solano County Supervisor John Vasquez.

    Gotham Greens owns and operates greenhouses in New York, Illinois, Rhode Island, Maryland and Colorado. Its products are currently available in more than 40 U.S. states and 2,000 retail stores. — By Pamela Kan-Rice, UCANR, and Jodi Genshaft, Gotham Greens