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Posts Tagged: Mark Mason
Drought focus of Water Resources IMPACT magazine special issue
UC ANR experts address emotional toll of drought
Preparing the American West for prolonged drought is the focus of a double issue of Water Resources IMPACT magazine. The California Water Commission staff are guest editors for this special open-access edition of the magazine, which is published by the American Water Resources Association.
Faith Kearns, academic coordinator of University of California Agriculture and Natural Resources' California Institute for Water Resources, is among the authors delving into how drought impacts people and the environment and how we can better prepare for the inevitable.
The first issue, published on Feb. 14, focuses on water scarcity issues confronting California and the ways these issues affect different sectors.
In “Trauma, Care, and Solidarity: Addressing the Emotional Toll of Chronic Drought,” Kearns highlights the effects of drought on mental health. She points to the spike in suicide hotline calls when wells ran dry in Southeast Asian communities in California's Central Valley.
By listening to Southeast Asian farmers, Ruth Dahlquist-Willard and Michael Yang of UC Cooperative Extension were able to “lighten the load” for them by providing pragmatic support, Kearns writes.
“The scale of some of these highly emotional issues – drought, wildfires, climate change – can make them seem incredibly difficult, if not impossible, to deal with,” Kearns said. “At the same time, they are affecting everyone living in the western U.S. on a daily basis. I wanted to highlight and provide models based on work that people – whether they are researchers, clinical psychologists, or Cooperative Extension advisors – are doing right now to ease the way.”
The authors who contributed to the double issue are a diverse array of Tribal experts, academics, nongovernmental organization thought-leaders, water managers and water policy influencers, each of whom brings their own perspective on the topic of drought. Their expertise and perspectives in climate science, water policy and water management will help inform drought-related decision-making and support policies that better prepare the state to thrive during periods of prolonged water scarcity.
In addition to Kearns, the first issue includes articles contributed by:
- Samantha Stevenson, University of California, Santa Barbara
- Jay Lund, University of California, Davis
- Ron Goode, North Fork Mono Tribe
- Andy Fecko, Placer County Water Agency
- Jeff Mount, Public Policy Institute of California, and Ted Grantham, University of California, Berkeley/UC Cooperative Extension
- Nat Seavy and Karyn Stockdale, National Audubon Society
- Kjia Rivers, Community Water Center
- Cannon Michael, Bowles Farming
- Michelle Reimers, Turlock Irrigation District
The January/February edition of Water Resources IMPACT magazine can be accessed, free of charge, on the American Water Resources Association website at https://www.awra.org under “Publications.”
The second issue, to be published in March, will focus on drought response, considering the options for adaptation. This two-part series complements the Commission's work on strategies to protect communities and fish and wildlife in the event of a long-term drought.
New UCCE advisors bring fresh ideas to protect lettuce from INSV, Pythium wilt
Salinas Valley lettuce growers lost about $150 million in 2022 due to diseases
A stormy winter could portend another devastating year for the lettuce industry in the Salinas Valley, which saw approximately $150 million in lost gross revenue in 2022 due to INSV (impatiens necrotic spot virus) and associated diseases. Recent drenching rains might mean more weeds – overwintering “reservoirs” for the tiny insect, the Western flower thrips, that carries INSV.
Or the extreme precipitation could benefit growers, as thrips in the soil – during their intermediate stage of development – might be drowned in the waterlogged fields.
As with so many aspects of the INSV crisis, the ultimate effects of flooded fields on thrips populations remain unknown.
“We don't know if thrips are just so persistent and so stable in that pupal stage that maybe they will emerge unaffected,” said Kirsten Pearsons, University of California Cooperative Extension integrated pest management farm advisor for Santa Cruz, Monterey and San Benito counties. “There's just so much about their biology and ecology in the Salinas Valley that we just don't know.”
The mystery of thrips, INSV and soilborne diseases (namely Pythium wilt) is why UC Agriculture and Natural Resources assigned Pearsons to the area last November and hired Yu-Chen Wang in October as UCCE plant pathology advisor for the three counties.
“They're stepping in at a critical moment,” said Richard Smith, the region's UCCE vegetable crop production and weed science advisor who retired in January after a 37-year career. “They've gotten grants funded already – and that's just incredible. They're hitting the ground running.”
Experienced in disease diagnosis and collaboration with growers and industry partners, Wang said her pathology background – paired with Pearsons' entomology expertise – will be crucial in addressing INSV and other diseases.
“It is important for Kirsten and me to work together and provide different insights for the vector and the pathogen, respectively,” Wang said.
‘It's going to take everything to get a crop'
One priority is untangling the dynamics of INSV and Pythium wilt co-occurrence – the subject of ongoing research by JP Dundore-Arias, a plant pathologist at California State University, Monterey Bay. While the vegetables may tolerate one disease or the other, their one-two punch often deals the lethal blow.
“The challenge is – which is why it's great to have Yu-Chen and Kirsten – is that we have so many problems now, whether it's Fusarium (wilt), or Verticillium (wilt), or Pythium, or INSV,” said Mark Mason, pest control adviser for Nature's Reward, which primarily grows lettuces on 5,000 acres across the Salinas Valley.
Mason said that co-infections on his crops (sometimes with three or four diagnosed diseases) make it difficult to assign monetary damages to a specific pathogen, but he noted he has seen fields with “100% loss.” According to the Grower-Shipper Association of Central California, about 11,500 acres were deemed not harvestable in 2022, representing 12% of lettuce industry acreage.
Given the gravity and complexity of the disease dilemma, Pearsons said she has been fielding calls from growers seeking new and better solutions – ways to improve existing tools, techniques borrowed from other crop systems, and additional biological or chemical means of control.
And although there are a couple of pesticides that manage the disease-carrying thrips reasonably well, growers and researchers are worried about their diminishing efficacy due to overuse. Plus, they only constitute a short-term fix.
“Managing the thrips will only reduce the amount of INSV that can get transmitted,” Pearsons explained. “You can kill 99.9% of the thrips, but you get one thrips that has INSV that enters a field, and now you have an infected lettuce plant. All of the thrips are going to come and they can spread it from there; pesticide slows things down, but it's not going to eliminate it.”
Finding disease-tolerant lettuce cultivars is a more sustainable approach. Trials conducted last year by Smith, Wang and others identified several varieties that appeared to hold up well to Pythium and INSV. While additional research could maximize their potential benefit, Wang said even the hardier cultivars will lose their resistance over time, and a multi-layered INSV strategy with “integrated management tools” is crucial.
“We realized, when this thing started happening, that we cannot spray our way out of this problem,” Mason said. “We need varieties; we need management practices; we need pesticides…it just seems like it's going to take everything to get a crop.”
Weeds key to disease control
An all-hands-on-deck approach helped control thrips-harboring weeds last winter. With fields drying out from January storms, Smith said communities must get back to weed management – with a focus on prominent weed hosts for INSV and neglected areas adjacent to farms. Hotspots of infection last year were traced to industrial lots that were overlooked during the weeding process.
“People can't lose sight of the fact that we still need to be controlling the weeds in key areas, because that's the reservoir of the virus during the winter,” Smith said. “We have to stay on task with that.”
Yet despite the diligent weed abatement, crop damage from INSV and Pythium was widespread in 2022, and Smith said it's “very possible” that high heat during the summer was a contributing factor to especially prevalent disease in fall. Thrips populations tend to thrive in warmer weather, Smith said, but much more research needs to be done to understand the basic biology of the insect, including how they acquire the virus and how they spread it.
High hopes for future
Pearsons cited the work of Daniel Hasegawa, a research entomologist with the U.S. Department of Agriculture, who leads teams in monitoring thrips populations in several locations across the Salinas Valley. Currently the counting of thrips on sticky card traps is done manually, but Pearsons and Mason mentioned the possibility of using AI and machine learning to expedite that process.
Mason said that the grower community is excited about the new technologies and ideas that Pearsons and Wang are bringing to the region. As a participant in the search for candidates to fill the advisor positions, Mason said “they were, in my opinion, by far the best fit for what we were looking for.”
“I hope they stay here for 30 years,” he added.
The new advisors both noted the palpable energy and cooperative spirit in the Salinas Valley to proactively meet the challenge.
“Looking to the past, there have been other outbreaks and diseases that they've managed to overcome,” Pearsons said. “These farmers are resilient and creative and I fully believe that lettuce will still be growing here for years to come – it might look a little different, and it might take a little bit of a painful period to get to that point, but I think that we're going to be able to come up with some solutions.”
And while there are concerns that some lettuce growers might decide to leave the region, Wang said she also believes in the industry's strong roots and rich history.
“Salinas Valley has had a beautiful climate for lettuce for so many years; there are some undeniable advantages here,” she said. “This is still the best place in the United States – and maybe the world – to grow lettuce.”
Your water-efficient landscape doesn’t have to be barren
UC climate-ready landscape trials identify low-water yet attractive plants
Good news: roses can be a part of your water-efficient landscape. Lorence Oki, UC Cooperative Extension environmental horticulture specialist in the UC Davis Department of Plant Sciences, identified rose cultivars that remain aesthetically pleasing with little water.
Oki is the principal investigator of the Climate-Ready Landscape Plants project, which may be the largest irrigation trial in the western U.S., and the UC Plant Landscape Irrigation Trials (UCLPIT), the California component of that project. These projects evaluate landscape plants under varying irrigation levels to determine their optimal performance in regions requiring supplemental summer water.
“There are some assumptions that pretty plants use a lot of water, like roses,” Oki said. “Everyone thinks they need a lot of water, but we've found some that don't, and they still look great. A water-efficient landscape doesn't need to look like a Central Valley oak-grassland in the summer. It can look really attractive.”
In 2021, Oki's team at UC Davis identified Lomandra confertifolia ssp. pallida "Pom Pom" Shorty and Rosa "Sprogreatpink" Brick House® Pink as two of the best low-water plants in the trial.
“The useful tip or information that is shared at the end of each trial is the selection and designation of plants as Blue Ribbon winners. These are the plants that looked good with an overall rating of 4 or higher throughout and were on the low (20%) water treatment,” said Natalie Levy, associate specialist for water resources, who manages the project at the UC ANR South Coast Research and Extension Center.
How plants earn a blue ribbon
Each trial year, the selection of new plants is based on research recommendations and donated submissions from the nursery industry. The landscape plants are trialed in full sun or 50% shade cover.
Irrigation treatments are based on the rate of evaporation and plant transpiration (evapotranspiration) measured through a local California Irrigation Management Information System (CIMIS) weather station that provides a reference evapotranspiration (ETo) rate.
Three levels of irrigation are provided to the plants equal to 20%, 50%, and 80% of ETo. The volume of water applied is the same at each irrigation based on soil characteristics, but the interval between applications varies with weather and the treatment. Using this method, irrigations for the 20% treatment are less frequent than the 80% treatment.
“The 20% treatment during the 2022 trial was irrigated an average of once per month while the 80% treatment was irrigated weekly,” explained Levy.
During the deficit irrigation trial, monthly height and width measurements are taken to determine the plant growth index. Monthly qualitative aesthetic ratings on a scale of 1 to 5 are determined for foliage appearance, flowering abundance, pest tolerance, disease resistance, vigor and overall appearance.
A second round of flowering abundance and overall appearance measurements are also taken to capture more of the blooming period. For example, UCLPIT identified in the 2020 trial at South Coast REC that the "Apricot Drift" rose had a mean overall appearance score of 3.5 out of 5, deeming it “acceptable to very nice” and a low water use plant within the Water Use Classification of Landscape Species or WUCOLS guide.
Project expands options for landscape planting
“(WUCOLS) only has 3,500 plants in it. There are guesses that there are close to 10,000 cultivars in urban landscapes in California, if not more,” said Oki. “WUCOLS also didn't have numerical ratings. Instead, you'll see verbal ratings like ‘low water use' or ‘high water use.'”
The UCLPIT project has not only developed numerical recommendations for irrigation, but it has also added new landscape plants that are compliant with California's Model Water Efficient Landscape Ordinance. In fact, UCLPIT's data is one of the few sources that can be used to supplement WUCOLS.
Geographic diversity of trial sites adds to knowledge base
In addition to UC Davis and South Coast REC in Irvine, the trials have expanded beyond California as the Climate-Ready Landscape Plants project and is in progress at Oregon State University, University of Washington, University of Arizona and Utah State University thanks to a USDA/CDFA grant awarded in 2020.
Lloyd Nackley, associate professor of nursery production and greenhouse management at Oregon State University, is the principal investigator of the trial in the Portland metro area, which is entering its third year.
“People know that there are drought tolerant plants, but there are many. We're trying to highlight lesser known or newer varieties. And even though the trial is three years, most gardeners would hope that their garden lasts longer than that,” said Nackley.
One of the observations that Nackley recalls is of the Hibiscus Purple Pillar plant. Unlike the trial at South Coast, the Purple Pillar did not perform well in Oregon in the spring.
“It wasn't until August that we saw the plant bloom and begin to look like what we saw from South Coast in April,” Nackley said.
Ursula Schuch, horticulture professor and principal investigator of the trial taking place at the University of Arizona, was also surprised at the range of performance among different plant types and the effects of irrigation, heat and temperature.
“This research will reassure green industry professionals that they can stretch their water budget to successfully cultivate more plants, watering them according to their needs instead of irrigating every plant according to the highest water-using plants,” said Schuch.
Although research is only conducted in the West, the hope is that there will be trials in other regions of U.S.
Doing so would yield comprehensive information about the plants and their performance in different climates. As extreme weather events persist in the U.S., disease pressure and risks do too. Trials throughout the country would provide location-specific data regarding disease susceptibility.
To learn more about the UCLPIT research project, visit https://ucanr.edu/sites/UCLPIT/
Plant Suggestions for your Rain Garden
Last week in this column we suggested creating a swale in your home garden to capture rain and practice effective water conservation. If you have been inspired to start planning a swale, you may be looking forward to the fun of selecting plants for this...
California fuchsia shrub, Jeanette Alosi
St. Catherine’s Lace buckwheat in bloom, Jeanette Alosi
Yarrow-achillea millefolium whilte, Brent McGhie
Hummingbird-sage, Brent McGhie
Eva Case' coffeeberry, Jeanette Alosi
Redbud in bloom, Jeanette Alosi
Ceanothus 'Concha,' Jeanette Alosi
Now is the time to plant climate-ready trees, says UCCE researcher
In a drought-prone region like Southern California, working with Mother Nature is not only wise but necessary, according to Janet Hartin, UC Cooperative Extension horticulture advisor for Los Angeles, San Bernardino and Riverside counties, who studies climate-ready trees.
In 2020, Governor Newsom launched the California Climate Action Corps, empowering Californians to protect their communities from the impacts of climate change. Newsom's call to action emphasizes the need for long-term and sustainable solutions like Hartin's research, which urges Southern California to care for existing trees and plant new ones.
In collaboration with the U.S. Forest Service and other UC Cooperative Extension scientists, Hartin is amid a 20-year research study identifying trees suitable for California's different climate zones. Her work provides a comprehensive understanding of trees and their benefits related to human and environmental health, particularly as Californians navigate climate change's evolving challenges.
One of these concerns is urban heat islands. UHIs are areas in which heat is reradiated from paved concrete or asphalt surfaces. In cities covered in asphalt, like Los Angeles, average temperatures can become six degrees hotter than surrounding areas.
To reduce urban heat islands, she has been working with community organizations to plant trees. In March, for example, Hartin teamed up with the Inland Empire Resource Conservation District to increase tree canopy in the Inland Empire.
Trees keep cities cool
To keep the city cool, some Los Angeles neighborhoods are repainting pavements with reflective coating. According to a 2020 study published in Environmental Research Letters, reflective coating can decrease pavement temperatures up to 10 degrees. As helpful as this is, augmenting urban landscapes to include heat-, drought- and pest-resistant tree species, whether native or not, can significantly reduce the impacts of urban heat islands too.
“Trees can cool impervious surfaces by 40 to 65 degrees,” Hartin said. During a 2021 study, in May and June Hartin discovered that unshaded asphalt could be more than 60 degrees hotter than shaded asphalt during late spring and early summer in inland and desert cities.
Other than providing shade, trees are effective at deflecting the sun's radiation and cooling the atmosphere through evapotranspiration. Given that they absorb and store carbon as well, trees lessen the impacts of pollution from fossil fuels.
“A well-tended mature landscape tree can absorb 40 tons of carbon over its lifespan,” said Hartin.
In a 2021 blog post, Hartin suggests trees be selected based on their adaptation to the “micro-climate” in each particular landscape, noting factors to consider like shade, proximity to buildings, space needs below and above ground, soil type and water source. She also recommends the Sunset Western Climate Zone maps for reference, noting that they are “more precise than USDA zones for our warmer climates.”
Based on the study with the U.S. Forest Service examining the performance of 12 species of underplanted but promising landscape trees at UC Riverside, favorable candidates include bubba desert willow and maverick thornless honey mesquite for their drought resistance, and red push pistache for its drought and heat resistance.
Tamara Hedges, executive director of UC Riverside Palm Desert Center and member of the Board of Directors for the Oswit Land Trust, agrees that trees are important in our fight against climate change:
“Through our partnerships with the UC California Naturalist and the Master Gardener Programs and many other nonprofits in the Coachella Valley, natural ecosystems are being protected and expanded and built environments cooled through the planting of appropriate tree species. These UC/USFS studies go a long way in identifying new underrepresented tree species."
General tips for planting
For California, planting in early fall through late winter provides ample time for trees to establish a strong root system before enduring the summer heat. Doing so also means that natural rainfall can fulfill water needs, as opposed to solely relying on irrigation systems.
Unlike newly planted trees, mature trees should be watered infrequently but deeply. Watering too often can reduce the level of oxygen in the rootzone and result in waterlogged soils prone to crown and root rots.
During the fall, trees only need about 15% of the water they would require in the summer. When watering, keep the tree trunk dry. Because the roots of the tree grow outward and are usually a foot deep into the ground, Hartin recommends watering the area around the trunk rather than the trunk itself. This will also help avoid water waste.
“Trees not adapted to the climate they're planted in and not receiving proper care are much more susceptible to invasive pests like shothole borers and diseases,” said Hartin. “Even the loss of one front yard tree can significantly reduce shade, increase the surrounding temperature, and diminish energy savings.”
