Posts Tagged: pest management

Diagnosing herbicide problems takes detective work

Field day offers examples, tips for solving the mystery

A grower applies an herbicide to his tomato plants, or thinks a neighbor's treatment is drifting over her almond trees. A short time later, the leaves start to bleach or shrivel. Was it the herbicide? Or maybe water stress? Soil nutrients? Perhaps an insect?

Figuring out the causes of crop problems takes detective work, and like solving any mystery, it starts with knowing the signs, gathering evidence and asking questions.

The Diagnosing Herbicide Symptoms field day at UC Davis was an opportunity to see, up close, the shriveled cotton, scorched corn and dying sunflowers that can result when herbicides are applied incorrectly. Using the right herbicide – in the right proportion, at the right time and in the right field – can make the difference between a thriving crop and a financial loss.

A top take-away to avoid problems: “Don't do stuff at night!” laughed Becky Wheeler-Dykes, a UC Cooperative Extension farm advisor attending the June 26 event to better serve growers in Glenn, Tehama and Colusa counties. “The packages look the same. People grab the wrong jug.” And then, disaster.

Instructors were Brad Hanson, professor of Cooperative Extension; and Kassim Al-Khatib, the Melvin D. Androus endowed professor for weed science; both in the Department of Plant Sciences. They were joined by John Roncoroni, a Cooperative Extension emeritus farm advisor rooted in the department's weed science program. Attendees were a mixture of people from agriculture, industry, government officials, university researchers and Cooperative Extension advisors. The event was hosted by the Weed Research and Information Center, based in the Department of Plant Sciences.

Out in a field west of campus, visitors could see the progression of damage, from control plots with green and healthy crops to plants that looked sadder as herbicide concentrations increased. Visitors could see the patterns of damage for common foliar chemicals such as glyphosate, paraquat, and 2,4-D, as well as soil-applied herbicides from several chemical classes.

“There's a lot of detective work,” said Stephen Chang, a master's student in Hanson's lab aiming for a career in Cooperative Extension. “For example, the company that makes the herbicide says there shouldn't be a problem, but the grower says, there is a problem. This course helps with developing the skills to figure out what happened.”

It might not be the herbicide at all

Detective work and problem-solving frame the approach, Hanson explained. The cause of crop damage can be simple or complex. Like a good mystery, what appears to be a clue can turn out to be a red herring. Professionals need to draw on their inner Sherlock Holmes to observe and document symptoms, look for patterns in the plants and in the field, ask questions, gather information about the larger environment and collect samples.

An herbicidal Agatha Christie would then suggest: What if it's not herbicide damage at all? Participants learned to consider the possibility of insects, pathogens and viruses, as well as problems with water, nutrients, soil condition and even root damage from cultivation practices.

Hanson recalled puzzling over symptoms he found in an orchard. The culprit? “A leaking natural gas line,” he said.

More resources for herbicide issues

Participants also heard from Molly Mathews, deputy agriculture commissioner from Yolo County, on how a field investigation is conducted. Lawyer Robert Davies, of Donahue Davies LLP in Folsom, outlined the basics of what happens when there are lawsuits related to crop damage from herbicide drift.

The Diagnosing Herbicide Symptoms field day is part of a larger program of education and outreach offered through the Weed RIC, said director Julia Stover-Blackburn. It was the first time the event has been offered since the COVID-19 pandemic, she added.

• For more information about field days and resources, visit the Weed RIC webpage.
• For a thorough discussion of herbicide symptoms, visit this page overseen by Al-Khatib and sponsored by University of California Agriculture and Natural Resources.
• This online course follows an earlier version of the Diagnosing Herbicide Symptoms field program.

This story was originally published on the UC Davis Department of Plant Sciences website.

Report outlines top concerns in California organic agriculture

Organic Agriculture Institute needs assessment refines how it can address pressing challenges

The explosive growth of organic agriculture in the U.S. – reflected in a 90% increase in organic farms from 2011 to 2021, according to U.S. Department of Agriculture statistics – has come at a cost for some farmers. With new farming operations increasing the supply of organic commodities, along with consolidation of buyers, growers report that their profit margins are not what they used to be.

Those market size considerations are among the challenges highlighted in a new report detailing the initial findings by the University of California Organic Agriculture Institute on the most pressing needs of the state's organic sector. OAI gathered and analyzed data from 423 responses to an online grower survey, over 60 interviews with stakeholders across the organic community, and additional observations from farm visits and workshops.

The report describes other frequently mentioned systemic priorities, such as maintaining integrity of the term “organic,” developing a market for organic seeds, spreading consumer awareness, and alleviating the burdens of organic certification and reporting.

Shriya Rangarajan, the postdoctoral researcher with OAI leading this statewide needs assessment, said that the reported challenges varied by organic status (fully certified, transitioning to organic, or a mixed farm with some conventional), type of crop, as well as size of the operation. She noted survey respondents were roughly representative of the sector overall – 70% small-scale growers and 30% medium and large.

“Organic is not a homogenous industry, to say the least – small growers and large growers are very different; for small growers, their challenges tend to be financial and regulatory, especially relating to certification requirements and labor,” said Rangarajan. She added that larger growers mentioned different types of challenges, weeds and pest pressures for instance, given the difficulty in controlling managing these at scale without the use or availability of organic inputs.

Organic Agriculture Institute key to sharing resources across state

Another common theme from the assessment is that the organic sector needs more accessible resources to address those myriad concerns. For OAI, established in 2020 under UC Agriculture and Natural Resources, the initial findings validated and refined the direction of its research and extension programs.

“As a new organization, we've been trying to figure out where we fit into this ecosystem and how we can support it,” said Houston Wilson, a UC Cooperative Extension entomology specialist who has served as OAI's director since its founding.

Because OAI was envisioned as a hub of resources and connections for California's organic community, Wilson and his colleagues are especially interested in understanding how its constituent members obtain information – and how OAI can improve their access.

“Growers are finding it difficult to navigate the resources that exist for organic agriculture, like technical information, financial support, compliance and certification support,” Wilson said. "While we'd like to see more resources for organic in general, those that currently exist can sometimes be hard to navigate or it can be hard to know where to go for the right thing – that became really apparent early on.”

While some producers are contacting OAI directly with their questions, Wilson is eager to develop tools and systems that can serve the community more broadly. For example, Wilson and Krista Marshall – OAI's policy and partnerships coordinator – are currently beta-testing a new map tool, built in conjunction with UC ANR's Informatics and GIS (IGIS) team. The map, expected to be ready in fall 2024, will enable users to click on their county and see all available resources related to organic agriculture.

Wilson added that OAI will have four full-time staffers by fall, further expanding its research, extension, and education efforts. After holding four field events this past year, OAI aims to increase activities in the coming year, including not just field events but also online resources, webinars and more. Also, a new training and technical assistance coordinator will be tasked with bringing Cooperative Extension advisors and other technical assistance personnel across the state up to speed on a range of organic topics, so they can more effectively answer questions from clientele in their region.

New survey aims to trace crucial organic knowledge networks

Although the OAI team has gained a sense of how information is shared across the organic community (and started to formalize those interconnections through a California Organic Agriculture Knowledge Network), they are now developing a survey to study those relationships more systematically.

“We're trying to understand what kind of knowledge resources people tap into, which is something that has come up repeatedly in our needs assessment,” Rangarajan said. “We're trying to understand who people are speaking to because, at the end of the day, organic is still a relatively small part of agriculture in California, and that makes it more fragmented. So trying to connect those different parts becomes important.”

Once Wilson has a more nuanced understanding of organic knowledge networks, he will be able to strategize and position OAI – and the UC – as a more effective partner and contributor in the sector.

“Given the history of organic, growers have had to rely on each other a lot,” Wilson explained. “We understand that the university has unique expertise to bring to the table, but we also acknowledge that there's all these other knowledge holders out there, so one of the roles that we see ourselves having is helping to facilitate those connections, strengthen them and increase the frequency of interaction.”

That may include further supporting efforts that connect transitioning organic farmers with experienced growers (a mentorship program led by Certified California Organic Farmers, or CCOF), or giving more structure to grower-researcher partnerships that can help address a host of production challenges. In OAI's grower survey, weed management topped the list, followed by water and disease issues, all exacerbated by climate variability.

“I think a lot of the real innovation changes are coming through growers experimenting with their own practice,” Rangarajan explained. “From a research perspective, one of the best ways to take this forward would be to formalize those experiments in some way so that knowledge becomes more reportable.”

And collaboration on “organic topics,” such as finding alternatives to synthetic pesticides, are a boon to the entire agricultural sector – conventional growers included.

“Everyone is trying to reduce pesticide use; everyone is trying to reduce environmental impacts,” Wilson said. “You don't have to be certified organic to benefit from organic research; these practices can be used by anyone.”

The report with OAI's initial findings on organic needs can be found at: https://ucanr.edu/sites/organic/files/396228.pdf.

UC Master Gardeners empower college students to garden for mental wellness

Although training is required to become a University of California Master Gardener, the benefits of gardening can be experienced by anyone and everyone.

“As long as you're willing to get your hands dirty,” said Laurie Menosky, a UC Master Gardener volunteer in Orange County, “you can learn to grow all sorts of things.”

In early April, Menosky partnered with ETN Medical Infusion (a clinic in Orange County) and the Sustainability Program for Student Housing at UC Irvine to teach students how to grow tomatoes. Menosky welcomed all in attendance, including families with toddlers who seemed fascinated by the 60 tomato plants atop one of the tables in the room.

The UC Master Gardener Program is a part of UC Agriculture and Natural Resources. During her presentation, Menosky taught participants how to choose varieties that fit their taste and growing environment, how to cultivate a thriving environment, and how to control pests and diseases using integrated pest management practices.  

“We have 16,000 residents at UCI and sustainability is one of our values. One of the ways we engage students is through on-campus gardens,” said Rachel Harvey, sustainability program manager for UCI Student Housing and a UC Master Gardener volunteer in Orange County.

UC Irvine has one teaching garden reserved for undergraduate learning, and three gardens operated and maintained by graduate students. “I was on the waiting list for a garden plot for a while, but it was totally worth the wait,” said Johanna Rinaman, a fifth-year Ph.D. student studying physical chemistry.

While the highlight of the event for many people was the opportunity to take a tomato plant home, another important takeaway was how gardening can be a good activity for your mental health. Sarah Nghiem, family medicine specialist at ETN Medical Infusion, who worked closely with Menosky, was instrumental in developing the mental health content for the day, encouraging attendees to attempt gardening with a mental health perspective.

Nghiem and her team received funding from the Orange County Health Care Agency through the Mental Health Services Act to work with transitional aged students (15-24 years-old) on understanding the importance of mental health, which led to the collaboration between UC Irvine, her alma mater, and the UC Master Gardeners of Orange County.

“I didn't do any gardening during the winter, and I felt a lot more anxious and depressed during that time,” Rinaman said. “I know gardening improves mental health because I've immediately felt a difference whenever I spend time with plants.”

Rinaman, whose father taught her a lot of what she knows about gardening, said that having access to a 4 feet by 6 feet plot to grow her own food is one of the many things she loves about UC Irvine.

Like Rinaman, Menosky turns to gardening to decompress, especially during the long days of summer. Teaching others about the physical and mental benefits of gardening gives her an opportunity to share her experience and, hopefully, help others find new ways to manage stress.

“We often have attendees come back years later telling us how our information has helped them and how much more they are enjoying their time in their gardens,” she said. 

To conclude her presentation, Menosky instructed participants to line up for their own tomato plant. Attendees took their plants outside to transfer them from a small pot to a grow bag – a type of container that helps root structure development.

Cassie Ekwego, a third-year transfer student studying civil engineering, couldn't hide her excitement after carefully lifting her plant. “I don't think I realized how attentive you need to be when working with plants,” said Ekwego, reflecting on what she learned from Menosky's presentation.

Now that she has her own plant to care for in her own home, Ekwego is eager to put her new knowledge to the test. “I love tomatoes, but this is going to be a huge responsibility for me,” she said.

Randy Musser, UC Master Gardener program coordinator for Orange County, said that while he enjoys talking to avid gardeners, bringing gardening to new people in the community is special to him. “This tomato workshop is particularly exciting for me because it is an opportunity for the UC Master Gardeners to grow our connection to UCI and young people just starting off on their gardening journey,” said Musser.

With a generous contribution from UC Master Gardener volunteer Sheila Peterson, Musser was able to purchase enough supplies to help attendees, like Ekwego, jumpstart their gardening experience.

Students, whose stress levels can skyrocket throughout the school year, value opportunities to be outdoors, try something new and be in community. “The garden is a different type of classroom. It's a place where students can learn and experiment, hopefully in a way that reduces stress,” said Harvey of UCI Student Housing.

Ekwego, who tried gardening for the first time while volunteering at UC Irvine's teaching garden, is just one of the many students inspired by their experiences. “Gardening reminds me that it's OK to get my hands dirty,” Ekwego said.

UC ANR adds 9 experts in water, wildfire, pest management and more

To help more Californians address challenging issues, University of California Agriculture and Natural Resources has hired UC Cooperative Extension experts to work in communities stretching from Humboldt and Siskiyou counties in the north, and south to San Diego County. State funding has enabled UC ANR to expand its expertise.

Since 1914, UC Cooperative Extension's researchers have been working directly with community members to improve the lives and livelihoods of Californians.

The nine recently hired UC Cooperative Extension specialists and advisors bring expertise in forestry, pest management, water, plant disease, horticulture, toxicology, economics, rice farming and wildfire.

To see a list of UC Cooperative Extension advisors who have joined in the past few months, visit https://ucanr.edu/About/DirectorySearch/Recent_Hires. The most recently hired scientists are introduced below.

Gill joins UCCE as environmental horticulture advisor

Haramrit Gill joined UC Cooperative Extension on April 1 as an environmental horticulture advisor for Tulare, Kings, Fresno and Madera counties.

She will be identifying landscape plants that are heat-tolerant, disease-resistant and fire-resistant. Gill will be researching California native plants with sustainable attributes that include superior adaptation, biodiversity enhancement, water efficiency and soil health benefits.

A native of Punjab, India, Gill earned her undergraduate degree in agriculture followed by a master's degree in horticulture at Punjab Agricultural University, where her research focused on micropropagation and haploid production in muskmelons. She earned a Ph.D. from the Department of Horticultural Sciences at Texas A&M University.

Her early research investigated the impact of nitrogen on spinach root architecture. Her doctoral work concentrated on rose breeding and deciphering the genetic underpinnings of flower color transition traits, fragrance and dwarfing in roses, with a particular focus on the intriguing phenomenon of flower color transformation from yellow to dark pink as blooms matured. She also collaborated on projects aimed at enhancing heat tolerance and disease resistance in roses. 

Gill is based at the UCCE office in Tulare and can be reached at hamgill@ucanr.edu.

Jordan joins UCCE as forestry and natural resources advisor 

Christian Jordan joined UCCE on March 18 as a forestry and natural resources advisor for Shasta, Siskiyou and Trinity counties. He will work to advance forest resilience and sustainable management on private and public lands, with a focus on conifer forest resource management and sustainable natural resources. 

In 2020, Jordan completed a Master of Forestry at UC Berkeley, with an emphasis on forest resilience in the context of increasingly severe wildfires. Prior to joining UC ANR, he worked in the private sector in defensible space and home hardening, installing residential exterior sprinkler systems for ember defense.  

Jordan brings a diverse educational and work background to the position. In 2014, he earned a bachelor's degree in geography from UC Berkeley, writing a thesis on future climate and viticulture in Napa and Sonoma counties. Upon graduating, he worked in the wine industry before returning to natural resources. 

Jordan is based at the UCCE office in Redding and can be reached at cjordan@ucanr.edu.

Pastrana joins UCCE as plant pathology advisor 

Ana Pastrana joined UCCE on Jan. 16 as a plant pathology advisor serving Imperial, Riverside and San Diego counties.

In her role, Pastrana will collaborate with pest control advisers and support growers with disease management. In addition to identifying high priority concerns, she will conduct research and develop educational content that addresses growers needs.

Before moving to Southern California, Pastrana worked as a research scientist on plant pathology at the University of Seville, Spain, and at Vineland Research and Innovation Center in Canada. Previously, she completed a postdoctoral assignment in the Department of Plant Pathology at UC Davis in the Thomas Gordon Lab, where she specialized in soilborne diseases affecting strawberries and blackberries. 

While attending the University of Seville, Pastrana earned master's and bachelor's degrees in biology. At Investigación y Formación Agraria, Pesquera, Alimentaria y de la Producción Ecológica, a government institution in Spain, she earned a Ph.D. and completed her dissertation on strawberry diseases. 

“At that time, Europe banned methyl bromide and other soil disinfectants. Strawberries rely on these disinfectants so plenty of soilborne diseases emerged,” Pastrana said. 

Originally from Seville, Spain, Pastrana said that her small hometown is surrounded by plum and citrus trees. Her mother, like many others, worked in the agricultural industry and Pastrana wondered how plant life works, inspiring her to study biology. 

As a Ph.D. student, Pastrana didn't know she would pursue plant pathology specifically because she was open to studying diseases in general whether it be humans, animals or plants.

“Plant pathologists are like doctors. Not everyone is happy to work with us because it usually means that there is some sickness involved,” said Pastrana. “But if growers work with pathologists from the beginning, we can focus on preventative care and helping to protect plants from getting sick.” 

Pastrana is based at the UCCE office in Holtville and can be reached at ampastranaleon@ucanr.edu.

Mokwunye named area IPM entomology advisor 

Idongesit Mokwunye joined UCCE on Jan. 3 as an area integrated pest management entomology advisor.

She will be studying insect pests of economic importance affecting tree fruit and nut crops, such as pistachio, almond, walnut, table grapes and stone fruit. Major pests include navel orangeworm, mealybug, carpophilus beetle, mites and scale insects.

Prior to joining UC ANR, Mokwunye worked as a nut crop entomologist at the Cocoa Research Institute of Nigeria for over 15 years and headed its Crop Protection Division.

“My journey into entomology as a career started when I was posted to the Cocoa Research Institute of Nigeria for the mandatory one-year National Youth Service Corp,” Mokwunye said.

“I was really fascinated at the diversity and economic importance of the insect species (both beneficial and pests) on agricultural crops and natural landscapes generally,” she said. “The hands-on lab experiments and field activities were exciting, engaging and inspiring. I was actively involved in setting up experiments, data collection, data entry and informal discussions on research projects. I was seeing the insect world in an entirely different perspective.” 

She already held a bachelor's degree in zoology from the University of Lagos, Nigeria.

“The then-head of the department observed my interest and encouraged me to get a master's degree,” said Mokwunye, who then earned a master's degree in entomology from the University of Ibadan, Nigeria. “During the course of the second degree, I got a job in the same institute and today the rest is history.”

Mokwunye holds a Ph.D. in entomology from the Federal University of Agriculture Abeokuta, Nigeria. Her research interests include integrated pest management, chemical ecology, extension entomology and economic entomology. She has worked on the population dynamics of the cashew stem girdler as it correlates with weather parameters, its damage potential, semiochemical interactions and chemical control of insect pests.

She has served as a resource person engaging stakeholders in outreach activities and facilitating training programs on good agricultural practices. In addition to publishing more than 25 research articles, she is a fellow of African Women in Agricultural Research and Development, Orange Knowledge Program of the Netherlands Government, and Scientific Exchanges Program of the USDA. 

“I am delighted to be here as a UC Cooperative Extension advisor and I hope to bring my expertise and experience in pest management to bear,” she said. “I plan to connect and engage meaningfully with my clientele in order to understand their needs, priorities and perspectives regarding pest management issues.”

Mokwunye is based at Kearney Research and Extension Center and can be reached at (559) 807-0257 and imokwunye@ucanr.edu. 

UCCE water advisor Garza hopes to foster ‘spirit of shared responsibility' 

Laura Elisa Garza Díaz joined UC ANR on Jan. 3 as the UC Cooperative Extension water quality, quantity and climate change advisor for Lake and Mendocino counties, focusing on how intensified droughts, floods, wildfires and other climate impacts affect water supply and quality.

She aims to address Sustainable Groundwater Management Act requirements and enhance local water resilience in collaboration with farmers and natural resource managers, local government water agencies, water districts and other key stakeholders. 

In addition to guiding policymakers in creating comprehensive water-resiliency plans covering development, storage, alternative sources and conservation, Garza – who is fluent in Spanish – will share water research with a diverse range of communities.

“I aim to empower local stakeholders by providing them with the knowledge and tools needed to navigate the complex landscape of water quality, quantity and climate change,” she explained. “My goal is to foster a spirit of shared water responsibility, and ensure that water management practices consider the needs of all – for a more just and inclusive environment for everyone.”

Originally from Monterrey, Mexico (“the city of the mountains,” as she puts it), Garza earned her bachelor's degree from Tecnológico de Monterrey. After completing an Erasmus Mundus joint master's degree program in applied ecology, Garza worked as a specialist with the Water Center for Latin America and the Caribbean.

While pursuing her Ph.D. at UC Davis, she served as a scientific advisor for Pronatura Noroeste, an environmental protection organization, and started the Women in Science Interview Sessions at the Permanent Forum of Binational Waters, where she volunteered. It is an initiative to interview women who have worked or researched water topics in the Rio Grande/Rio Bravo Basin.

After obtaining her Ph.D. in hydrologic sciences from UC Davis, Garza worked as a project manager for the Washington Water Trust in Washington.

At every step of her journey, Garza has been motivated by a deep passion for safeguarding water resources and fostering resilient ecosystems and communities.

“I find inspiration in the intersection of science, community engagement and sustainable water management,” she said. “The opportunity to contribute to the well-being of local communities and the environment drives my commitment to addressing water challenges in a changing climate.” 

Based at the UCCE office in Ukiah, Garza can be reached at legarza@ucanr.edu and (707) 463-4495.

Agyeman joins UCCE as economics advisor for Butte, Glenn and Tehama counties 

Domena Agyeman joined UCCE Jan. 3 as an agriculture and natural resources economics advisor for Butte, Glenn and Tehama counties. 

Prior to joining UC ANR, he was a postdoctoral associate at the Virginia Seafood Agricultural Research and Extension Center at Virginia Tech University.

As a UCCE advisor, Agyeman will provide insights that ensure economic profitability of all agriculture activities, including orchards, rice, forestry and other natural resources-based businesses in those counties. He will also promote broadband access and contribute to regional economic development.  

“I am excited to leverage my expertise to highlight the economic contributions and impacts of the agriculture and natural resources industries in Butte, Glenn and Tehama counties,” Agyeman said, “and to provide producers and other stakeholders in the region with research-based information that will help them navigate their business challenges and opportunities.”

His research interests encompass natural resources and environmental policy impact assessments, economic contributions and impacts analyses, producer decision-making assessments, and consumer preferences assessments.

“To get started, I will be doing a needs assessment, focus group meetings and surveys of target groups,” he said.

Agyeman earned a Ph.D. in agricultural economics from the University of Kentucky, a master's degree in agricultural economics from Mississippi State University and bachelor's degree in agricultural science from University of Cape Coast in Ghana.

Agyeman is based at the UCCE office in Oroville and can be reached at dagyeman@ucanr.edu.

Marsh named rice advisor for Colusa and Yolo counties 

Sarah Marsh joined UCCE on Jan. 3 as a rice farming systems advisor serving Colusa and Yolo counties.

Prior to joining UCCE, she worked in rice breeding research and integrative pest management with several row crops in the Upper Gulf Coast region.

She earned a master's degree in horticulture and agronomy at UC Davis, where she worked with Kassim Al-Khatib, professor of plant sciences, studying weeds and herbicide resistance in rice agroecosystems. She holds a bachelor's degree in plant and environmental soil science from Texas A&M University.

“I grew up on a diversified row-crop and orchard farm in Arbuckle and am grateful for the opportunity to serve the community in which I was raised,” Marsh said. “I hope to spend the first few months getting to know the growers and community of this region and learning what the unique needs of our area are.”

Marsh is based at the UCCE office in Colusa and can be reached at smarsh@ucanr.edu and (530) 415-7052.

Woelfle-Hazard joins UCCE Humboldt-Del Norte as fire advisor 

Cleo Woelfle-Hazard joined UCCE on Jan. 3 as a fire advisor for Humboldt and Del Norte counties. He will support residents, landowners, planners, land managers, tribes and Native fire practitioners in making North Coast communities more resilient in the face of intensifying wildfires.

His research and extension programs focus on climate resilience, cultural burning, fire-water interactions and training a diverse fire workforce.

Woelfle-Hazard collaborates on research with Native nations, agencies and local community members. In collaboration with the Karuk Department of Natural Resources, he is exploring future fire scenarios in the Klamath Basin and how streamflow would change. They are also exploring how fire and flooding can be renewed to revitalize habitat for ecocultural species such as willow, grape, salmon, elk and eel.

His past projects have included community-directed river research with frontline communities in Seattle, the Yukon-Kuskokwim Delta and Sonoma County. Using his expertise in home water and wastewater systems, he evaluated health and economic aspects of water delivery in Oakland and Hubli-Dharwad, India.

As a co-investigator on the Humanities Education for Anti-Racism Literacy project, Woelfle-Hazard collaborated on creating pathways to higher education for Native youth, and for training students to engage in respectful collaborations with Native partners.

He earned a master's degree and Ph.D. in energy and resources at UC Berkeley, where he convened scientists and Sonoma County residents to experiment with capturing winter rain to increase summer streamflow to benefit juvenile salmon, and exploring the possibilities of working with beavers to create cool refuges for coho. He also holds a bachelor's degree in interdisciplinary geosciences from the University of Montana.

Woelfle-Hazard is based in Eureka and can be reached at cwhaz@ucanr.edu.

Jegede joins UCCE as agricultural toxicology specialist 

Olukayode “Kayode” Jegede joined UC ANR on Jan. 2 as an assistant professor of Cooperative Extension for agricultural toxicology with the Department of Molecular Biosciences, School of Veterinary Medicine and Department of Environmental Toxicology in the College of Agricultural and Environmental Sciences at UC Davis. 

Jegede will be studying contaminants of agricultural importance in California, such as pesticides, metals, microplastics, veterinary pharmaceuticals, PFAS, fertilizers and their effects on humans, animals (including aquaculture) and environmental health of soil and plants.

“I will also be looking at various exposure pathways of these contaminants and interactions through food, water, soil and how climate change or other major environmental change events can influence toxicity of these contaminants and mitigation strategies,” Jegede said. “My research will also have a “one-health” perspective to it.”

Prior to moving to California, Jegede was a postdoctoral research associate at the Department of Soil Science, University of Saskatchewan, Canada for a year before moving to Wageningen University and Research in the Netherlands to work as a research scientist focused on terrestrial ecotoxicology.

His past research has examined the effects of metals, pesticides and mixture toxicity on soil biota (mites, springtails, snails, earthworms) and soil enzymes, related ecosystem service function and generating data for environmental risk assessment of metals and pesticides.

“I look forward to helping solve toxicology issues in California through research, advising on and promoting good health for everyone and everything connected to small and large-scale agriculture in California.” Jegede said.

He earned his Ph.D. in toxicology at the University of Saskatchewan in Canada and bachelor's and master's degree in zoology at the Obafemi Awolowo University in Nigeria.

Jegede is based at UC Davis and can be reached at ojegede@ucdavis.edu.

 

Almond growers should prepare for possibility of unusual disease outbreak

Wet winter, El Niño create favorable conditions for aerial Phytophthora pathogen

With heavy rains in the forecast amid strengthening El Niño conditions, almond growers should be on the lookout for a rare disease that can cause severe damage to their orchards, according to Florent Trouillas, a University of California Cooperative Extension specialist in fruit and nut pathology.

Phytophthora, soilborne microorganisms dubbed “water molds” because of their dependence on water, typically cause root and crown rot at the base of trees. But a few aerial Phytophthora can travel upwards and infect the higher parts of the tree. One species – Phytophthora syringae – is drawing special attention due to an unprecedented outbreak last winter, fueled by the atmospheric rivers that lashed California.

“It was found statewide – meaning in every almond-producing county – and disease incidence in orchards ranged from 10% of the trees infected to 75%,” said Trouillas, a UC Davis plant pathologist whose lab is based at UC Agriculture and Natural Resources' Kearney Agricultural Research and Extension Center in Parlier.

Trouillas and his colleagues, UC Davis graduate student Alejandro Hernandez and UC Riverside plant pathology professor Jim Adaskaveg, recently published a detailed online article describing the pathogen, which can infect a range of crops but mainly impacts almonds in California.

Although it doesn't kill the tree, the disease causes branch dieback that requires significant additional work and expense for almond growers. In 2022, almonds were the state's fourth-highest valued commodity, at $3.52 billion.

During last year's aerial Phytophthora outbreak, researchers also observed a new and troubling phenomenon: P. syringae, historically known to attack the cuts caused by pruning, was directly infecting the young shoots on almond trees – without any wounds.

“This was really the first time we had seen widespread evidence of infection on the twigs,” Trouillas said.

Although generally rare, outbreaks of P. syringae have been traditionally associated with wet El Niño years, according to Trouillas – and recent and persistent rain across the state should have growers on high alert.

Prune in dry weather, monitor, mitigate if necessary

While almond growers tend to prune during the downtime of winter, they should keep an eye on the forecast and aim for a 10- to 14-day window of dry weather to perform those tasks, whether training young trees or maintaining the established ones.

“If growers were to prune around a rain event – before, during or shortly after – this increases the likelihood of infection because this pathogen moves around with water,” Trouillas explained.

Researchers speculate that P. syringae, normally found in the soil, gets carried into the upper parts of a tree through strong winds and heavy rain. Alternatively, harvest processes like shaking and sweeping also produce air movements that may blow the microorganism into the canopy, where it waits for a favorable wet environment. The pathogen then attacks the wounds or young shoots, producing characteristic cankers and gumming.

The patterns and colors of the gum balls are keys to diagnosing an infection of this particular aerial Phytophthora. Starting around bloom time (mid-February), growers should monitor pruning wounds and young shoots on their trees, especially in the canopy, for signs of the disease.

The unique coloration of the gum balls – ranging from gold and amber to dark burgundy to bright red (see photos) – generally indicates P. syringae infection. But growers are urged to contact their local Cooperative Extension advisor for confirmation.

“It is super critical for growers that, whenever they see gumming, not to assume that it is this aerial phytophthora, because there are many other diseases that can cause gumming on the tree,” Trouillas said.

If the diagnosis is confirmed, growers may apply a compound that can mitigate the infection. The plant pathologists' recent writeup describes several curative treatment options, as well as a preventive measure that reduces the amount of pathogen in the soil and thus the likelihood of infection.

For more information on the pathogen's history and biology, as well as various options for disease management, visit the article on Sacramento Valley Orchard Source: https://www.sacvalleyorchards.com/almonds/trunk-soil-diseases/aerial-phytophthora-outbreaks-in-wet-years.

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