Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
University of California
Division of Agriculture and Natural Resources

News stories

South Coast REC program educates, trains future ag workforce

GROW program also builds skills of students with learning differences

High school students taste a variety of fruits grown and harvested at the South Coast REC during a GROW field day. Photo by Saoimanu Sope.

Renowned for pioneering research that leads to exciting new crop varieties like the Luna avocado, the University of California South Coast Research and Extension Center (REC) in Irvine is also an important hub for agricultural education. Through programs like the GROW program, South Coast REC – administered by UC Agriculture and Natural Resources – is a dynamic resource for workforce development in the community.

Originally created by the Orange County Farm Bureau, GROW provides out-of-the-classroom experiences in agri-business, career exploration and other educational opportunities for local high students in school districts with agriculture programs. Participants engage in field days at South Coast REC to learn about the research component of agriculture, and the research center quickly became a popular aspect of the program.  

In 2016, South Coast REC stepped in to oversee GROW. Tammy Majcherek, UC Cooperative Extension community education specialist for Orange County, has been at the forefront of the program's successful partnership between the Orange County Farm Bureau and the REC.

“Each field day we host is different, and that's intentional,” said Majcherek. “The students aren't just learning about agriculture – they're experiencing it. During their visit, they see where their food comes from and realize that agriculture isn't just planting seeds or hopping on a tractor.”

Students tour South Coast REC during a GROW field day. Photo by Saoimanu Sope.

In 2023, GROW reached more than 600 high school students and continues to nourish the minds and lives of Orange County community members. Students interact with UCCE advisors, industry partners and other experts to learn about a wide variety of topics related to agriculture including hydroponics and emerging ag technologies, pest management, food safety and preservation, plant breeding and more.

Andres Martinez, a junior at Fullerton Joint Union High School in Orange County, recently visited South Coast REC for a GROW field day and said it surpassed his expectations. "Everything was cool. I thought we were just going to be sitting in a classroom but my expectations definitely got blown out the water," he said, adding that he loves to eat and his favorite part of the visit was trying new food.

Martinez admitted that the visit deepened his interest in agriculture and he would like to return to South Coast REC to learn more about where his food comes from. 

Students from Fullerton Joint Union High School, including Andres Martinez (right), snack on lettuce grown in hydroponics at the South Coast REC. Photo by Saoimanu Sope.

Chocolate avocado pudding, anyone?

“We provide an opportunity for the students to see how growers, nutritionists and chefs intersect,” Majcherek said, noting that participants not only get to taste the crops harvested at South Coast REC, but they get to use it in creative dishes like chocolate avocado pudding.

Using cocoa powder, avocados, milk or milk alternatives and a sweetener, participants create a new and different snack. Thy Phan, a student at Westminster High School, recently visited South Coast REC for a GROW field day and said the pudding taste surprised her. “It didn't look that good when we were making it, but I actually like it,” she said.

“Of course, not all the students are going to like it but many of them are, at least, willing to try something new because they're involved in the process of creating it,” said Majcherek.

Jacob Ortigoza, another student from Westminster High School, confirmed that he was not a fan of the chocolate avocado pudding. “I didn't like the flavor, but making it was fun. I'd like to do more cooking,” he said.

GROW continues to expand its programming to serve students in various Career Technical Education programs, including cuisine, biology and mechanical engineering, as well as young adults in Adult Transition Programs.

A student from Westminster High School scoops chunks of avocado into a bowl to make chocolate avocado pudding. Photo by Saoimanu Sope.

GROW participants enter the workforce at SCREC

Adult Transition Programs (ATP) cater to 18- to 26-year-olds who have learning differences and are shifting from the student life to that of a young professional. Skill-building, for personal or professional use, is the primary focus of ATP and Majcherek was adamant about providing a space for ATP members to learn and explore at South Coast REC.

Gavin Olsen, who was a member of ATP at Esperanza Education Center in Mission Viejo, also learned of South Coast REC during a GROW field day. Despite growing up in Orange County, Olsen admitted that he had no idea the REC existed, but is glad he finally does.

“I grew up knowing about agriculture and come from a family of farmers,” said Olsen, who dreams of owning land one day. “At South Coast, I'm learning what it takes to manage land and I'm understanding plants better,” he added.

Gavin Olsen picks vegetables during a GROW field trip to South Coast REC. Photo courtesy of Gavin Olsen.

Lindsey Pedroncelli, interim director of South Coast REC, envisions the center as a launch pad for success. “We not only want to highlight novel career paths to students, but we want to train and empower them to work in these spaces,” she said.

Earlier this year, Olsen was hired as a field technician, supporting matters like plowing weeds, setting up irrigation lines and preparing field plots. Olsen has dyslexia and said the nature of his work at South Coast REC requires him to be hands-on, which he loves and prefers over desk work.

“I love getting my hands dirty and I feel like the hands-on aspect of the job is the best part,” Olsen said.

Pedroncelli wants South Coast REC to continue serving students by providing a base of knowledge that will help them succeed in the various agricultural industries.

“Beyond teaching the basics, we aim to assist students in taking the next step – whether that be pursuing a certification or degree at a college or university, taking part in an internship, or getting their first industry job,” Pedroncelli added.

To donate and support the GROW program, visit https://give.ucanr.edu/forms/SCREC-GROW.

Olsen discards tree logs to help clear a field at South Coast REC. Photo courtesy of Gavin Olsen.
Posted on Monday, November 18, 2024 at 12:18 PM
Tags: agriculture (33), bureau (1), development (4), farm (5), food (57), Fullerton Joint Union (1), GROW (2), high school (2), Orange County (12), South Coast (5), students (17), Westminster (1), workforce (1), youth (17)
Focus Area Tags: Agriculture, Food

Virtual fencing ‘game-changer’ for ranchers grazing cattle

Tech can save ranchers time and benefit animals and land, becoming more viable

Cattle wearing solar powered virtual fencing collars.

After the Caldor Fire destroyed seven miles of fencing on their cattle ranch in 2021, Leisel Finley and her family needed to replace the fence.

Finley, a sixth-generation rancher at Mount Echo Ranch in Amador County, said reconstruction costs were bid at $300,000 and would take at least a year to build, leaving the family without summer pasture and a herd of hungry cows to feed. Additionally, the U.S. Forest Service mandates that grazing be withheld for two years in postfire landscapes. This put the family in a difficult position.

While watching a recording of a California Cattlemen's Association meeting, Finley learned about a pilot program for virtual fencing. Desperate to find an alternative solution, she registered to try the livestock containment technology, which uses GPS enabled collars to monitor each animal's location in near real time.

Livestock producers can draw a perimeter on a map of their pasture using a laptop or smartphone application and send those instructions to the collar. The collar then uses audio and tactile cues to contain the animal in the area.

Eager to discover the short- and long-term benefits of virtual fencing, Finley turned to Scott Oneto, farm advisor, and Brian Allen, assistant specialist, from the University of California Cooperative Extension office in the Central Sierra. Since partnering with Oneto and Allen, Finley said she has come to understand and uncover more of the technology's potential.

The team has consistently observed the technology's value in integrating with and enhancing traditional livestock production systems across California. Though still in its early stages of development, the location tracking and containment system appears to provide time- and cost-savings that make it a game-changer for ranchers.

Ability to monitor location of animals in real time

Virtual fencing really stands out in its ability to monitor each animal's location in real time. During roundups, ranchers can use their smartphones to see their own location relative to their herd. The system can also send alerts if an animal crosses the virtual boundary or if a collar remains stationary for an extended period, potentially indicating that the animal is sick or that the collar has fallen off.

Rounding up cattle on large, forested grazing allotments can be challenging, as the process generally requires a group of people and many return trips to find every animal. Prior to virtual fencing, Finley and her father could gather about 85% to 90% of the herd in a week. Since using virtual fencing, Finley said one of their most recent roundups lasted three days, and they located every single cow.

Something that every livestock producer dreads is the notorious call from a neighbor or California Highway Patrol alerting them that one of their cows is out in the middle of the road. It always seems to happen at midnight or while they are out with friends or family. This scenario changes with virtual fencing.

Cows wearing a different brand of virtual fence collars.

Containment based on animal behavior

The containment system that virtual fencing is built on is based on animal behavior. When the animal crosses an invisible boundary, the collar emits an audio warning, prompting most animals to instinctively turn back into the desired area. If the animal doesn't respond, the collar delivers a mild electric pulse as a secondary deterrent.

Field trials by Oneto and Allen demonstrated the system's success. Recently, the team trained a herd of 37 cattle of mixed ages that had no previous exposure to virtual fencing. During the initial six-day training period, the cattle responded to the audio warning alone about 75% of the time when they approached a virtual fence boundary, with the remaining 25% of cases requiring an electric pulse.

After about three weeks, the herd was responding to audio cues alone about 95% of the time. The field trials also showed that the collars contain the livestock within the desired areas 90% to 99% of the time when the entire herd wears virtual fence collars and their basic needs for safety, connection to the rest of the herd, water, forage, shade, etc. are met.

Opportunities for improvement

While the technology is effective in its current capacity, there are notable areas where it can improve. One limitation to the system is the current reliance on cellular networks to operate. If an animal wanders into an area outside of coverage, the collar will continue to operate based on the last instructions but won't receive updates or report locations. This is especially a concern in many areas of California with poor cell reception, including the steep forested rangelands where many livestock producers have summer grazing allotments.

Another limitation is that some companies require a solar-powered base station with radio and cellular antennas to be placed on the pasture. These facilitate the transfer of animal locations and updates to the virtual fences. A base station going offline would create the same conditions as a drop in cell signal until the base station is repaired. Some companies are currently developing collars that bypass the need for these base stations.

The other major concern for ranchers is the cost for a virtual fencing system. The average rancher can expect to pay an estimated $20,000 to $30,000 in upfront costs. The cost to set up a base station alone is $5,000 to $10,000. However, this cost is highly dependent on several factors, including the manufacturer, the number of livestock to be collared, if the livestock are large or small ruminants, and the number of GPS base stations to cover the range.

According to Allen and Finley, the high cost of virtual fencing can be offset by the unique animal and land management benefits it can provide. “While physical perimeter fencing remains essential, VF is rapidly emerging as an innovative tool to control livestock with ease, precision, and flexibility in ways that were not previously feasible with traditional fencing,” Allen said.

Finley described the technology as a “game-changer” for her family.

Virtual fencing helps control invasive grasses, installing fuel breaks

Virtual fence successfully contained cattle within a three acre area to graze Medusahead, despite the presence of more desirable forage nearby, as indicated by the line grazed into the pasture.

While virtual fencing is designed to contain livestock without physical fencing, it is not intended to outright replace secure perimeter fencing. Instead, it operates best as a highly dynamic and adaptable cross-fence, allowing for more intentional grazing on the landscape to meet livestock production and natural resource conservation objectives within a secure physical perimeter.

With grant funding from the USDA Natural Resources Conservation Service, the UCCE team continues to work with Finley and other livestock producers to test these applications on California's diverse rangelands.

Within the Sierra Nevada and Coast Ranges foothills, these trials include using virtual fencing on cattle for targeted grazing of invasive grasses to support the recovery of native forage and installing fuel breaks within the wildland-urban interface to remove vegetation where the edge of a pasture meets urban housing.

Using virtual fencing, 25 cattle were successfully concentrated on a field of Medusahead (Elymus caput-medusae), an invasive annual grass. The herd respected the virtual fencing boundary 99% of the time despite nearby preferable forage. Grazing reduced medusahead seed heads from 2,072 per square meter in the ungrazed control area to just 68 per square meter in the grazed section.

GPS locations of virtual fencing collared cattle during a 3-week fuel break trial demonstrates how well animals respect the technology after proper training.

In a different trial, 37 cattle with virtual fencing collars were contained within 120-feet-wide fuel breaks along the boundary of an annual rangeland and residential area. Cattle stayed within the boundaries 99% of the time, leading to an 81% reduction in fine fuel biomass and lowering wildfire risk in the wildland-urban interface.

Within rangelands on conifer forests, these UCCE trials concentrate cattle on brush to reduce the flammable plants and vegetation that competes with desirable timber species. It also can prevent livestock from entering sites that are sensitive to livestock presence.

Upcoming grazing trials will focus on how virtual fencing works with goats and sheep. In addition to Oneto and Allen, UCCE's contribution to virtual fencing research is in large part due to Leslie Roche, UCCE specialist and associate professor at UC Davis, Dan Macon and Jeff Stackhouse, UCCE livestock and natural resources advisors, Kristina Horback, associate professor at UC Davis and Lone Star Ranch in Humboldt County.

To learn more about the trials led by the UCCE team,visit https://cecentralsierra.ucanr.edu/Virtual_Fencing/ 

Posted on Wednesday, November 13, 2024 at 11:23 AM
Tags: Brian Allen (1), cattle (34), Central Sierra (1), graze (2), ranch (2), rangeland (32), Scott Oneto (8), technology (14), virtual fencing (1)
Focus Area Tags: Innovation, Natural Resources

Extreme weather accelerates nitrate pollution in groundwater

UC Davis researchers insert a device that continuously collects water samples underground, providing real-time data on nitrate contaminant movement. Photo by Isaya Kisekka

Extreme weather spurred by climate change, including droughts and heavy rains, may increase the risk of nitrates from fertilizers ending up in groundwater, according to a recent study from researchers at the University of California, Davis. The study found heavy rains after a drought caused nitrates to seep 33 feet under farm fields in as little as 10 days. The study was published in Water Resources Research.

“The conventional wisdom was that it could take several weeks to years for nitrates to move from the crop root zones to reach groundwater,” said corresponding author Isaya Kisekka, a professor in the Departments of Land, Air and Water Resources and Biological and Agricultural Engineering. “We found these extreme events, such as California's atmospheric rivers, are going to move nitrate more quickly.”

In this study, different methods were used to measure how much nitrate, a component of nitrogen fertilizer, was seeping down through the soil in a tomato and cucumber crop near Esparto, California. Scientists conducted their research from 2021 until 2023 when California was experiencing periods of drought followed by atmospheric rivers. They measured nitrate during both the growing seasons and the rainy seasons.

Drought can leave more nitrogen in soil

Previous studies have shown about 40% of nitrogen fertilizer used for vegetables isn't absorbed by the plants but remains in the soil. During droughts, crops don't use nitrogen efficiently, leading to excess nitrogen in the soil. This study found that if a drought is then followed by heavy rainfall, that sudden burst of water causes nitrate to seep in groundwater more quickly. The nitrate concentration in the shallow groundwater exceeded the U.S. Environmental Protection Agency maximum contaminant level of 10 milligrams per liter for drinking water.

“In California, we often say we swing between droughts and floods,” said Kisekka. “These extreme events that come with climate change are going to make the risk of these chemicals ending up in our drinking water much more severe.”

Groundwater is the primary source of drinking water for most of California's Central Valley. In some regions, such as the Tulare Lake Basin, nearly one-third of drinking and irrigation wells exceed the EPA's safe nitrate level. High nitrate levels in drinking water can increase health risks, especially for young children. It may also increase the risk of colorectal cancer.

Need for real-time soil nitrate monitoring

Central Valley farmers are required to report to the Regional Water Board how much nitrogen they applied to their field and how much was removed as part of the crop's yield. The study compared different ways of monitoring when nitrate from fertilizers seep into groundwater. Kisekka said the results highlight the need for affordable, real-time soil nitrate monitoring tools to help farmers manage fertilizer use efficiently.

By using conservation practices that limit leftover nitrates in the crop's root zone after harvest, farmers can help reduce nitrate contamination in groundwater.  

This study's data will also help improve a model called SWAT, which is used to track nitrate seepage into groundwater across California's Central Valley. This effort is part of the Central Valley Water Board's program to regulate irrigated farmlands.

Other UC Davis authors include Iael Raij Hoffman, Thomas Harter and Helen Dahlke.

The study was supported by the USDA Natural Resource Conservation Service through its Conservation Effects Assessment Project. The national project is designed to assess the effectiveness of conservation practices across different watersheds. The study also had support from the USDA National Institute of Food and Agriculture.

Posted on Wednesday, November 13, 2024 at 10:26 AM
  • Author: Amy Quinton, UC Davis
Tags: drought (194), nitrate (13), water (115)
Focus Area Tags: Agriculture

UC ANR to focus efforts on issues where it can create greatest benefit

Strategic Vision 2040 prioritizes seven California challenges

Aiming to help tackle some of California's most pressing challenges, University of California Agriculture and Natural Resources has released its Strategic Vision 2040. The document serves as a blueprint to guide UC ANR's work, structure and resource allocation over the next 15 years to make a positive impact in communities across California.

The Vision was informed by thousands of comments and feedback from hundreds of UC ANR employees and community members – including program participants, government agency staff, elected officials, nonprofit groups, California Tribes, industry partners, farmers and producers.

As a long-trusted source for practical tools and information, UC ANR is the critical link between UC research and the everyday challenges affecting Californians' lives and livelihoods.

“UC ANR is uniquely positioned to cultivate, co-create and share science-based solutions on a wide range of issues in California, across the U.S. and around the globe,” said Glenda Humiston, UC vice president for agriculture and natural resources. “The Strategic Vision 2040 reaffirms our commitment to serve as a catalyst for collaboration and innovation in achieving a brighter future for all.”

The Vision document is the result of a 15-month process in which thousands of comments and feedback from hundreds of UC ANR employees and community members – including program participants, government agency staff, elected officials, nonprofit groups, California Tribes, industry partners, farmers and producers – were distilled and synthesized.

Informed by those insights, UC ANR refreshed its mission and vision statements and also identified seven distinct California challenges as priority areas in which UC ANR can make a significant impact:

Core Areas of Research and Programming

  • Agriculture and Food Systems
  • Natural Ecosystems and Working Landscapes
  • Thriving People and Communities

Overarching Issues

  • Climate Change
  • Innovation
  • Regulations, Policy and Compliance
  • Systemic Inequities

“It's important to note that these seven challenges are complex and interrelated, and demand the kind of interdisciplinary, collaborative approaches that UC ANR has become known for fostering and sharing,” Humiston said.

The seven challenges are complex and interrelated and will demand UC ANR's unique approach to generating, co-developing and sharing science-based solutions.

The Strategic Vision 2040 will provide direction for UC Cooperative Extension researchers and educators who bring their know-how and partnership ethic to all 58 California counties; UC ANR's 14 statewide programs and institutes; and approximately 20,000 volunteers in the 4-H Youth Development, UC Master Gardener, UC Master Food Preserver, and UC Environmental Stewards programs. UC ANR also supports a network of nine Research and Extension Centers, as well as productive collaborations among campus-based Agricultural Experiment Station faculty and UCCE advisors and specialists.

In the coming months, a UC ANR committee will develop a five-year Strategic Framework that will translate the Vision into action. Specific goals and objectives will guide UC ANR in its mission to cultivate thriving communities, sustainable agriculture, resilient ecosystems and economic prosperity.

The Strategic Vision 2040 document is found at: https://ucanr.edu/files/StrategicVision2040.pdf

Posted on Friday, November 1, 2024 at 2:27 PM

UC ANR experts, resources guide response to shothole borers in Bay Area

The expertise of UC Cooperative Extension advisor Beatriz Nobua-Behrmann, seen here training volunteers to spot signs of invasive shothole borers in Southern California, is now informing the ISHB response of Northern California communities. Photo by Krystle Hickman, UC IPM

UC Cooperative Extension scientists, partners managed invasive beetle in Southern California

Late in 2023, a potentially devastating beetle was detected in the San Francisco Bay Area for the first time. But land managers, arborists and agency staff have one big advantage as they devise plans to control the invasive shothole borers (ISHB).

Thanks to collaborations led by University of California Agriculture and Natural Resources, they can draw upon the hard-earned experience of their colleagues in Southern California. Over the past decade, SoCal communities have lost “tens of thousands” of trees due to ISHB infestations, according to Beatriz Nobua-Behrmann, UC Cooperative Extension urban forestry and natural resources advisor for Los Angeles and Orange counties.

In one regional park, about 500 trees had to be removed in the span of just one year. “That kind of impact happened in many locations; a whole street might lose 90% of the trees – all of a sudden,” said Nobua-Behrmann, a member of a statewide network studying ISHB.

An adult female invasive shothole borer measures only about 2 mm in length. Photo by John Kabashima

Spurred by such severe impacts, UC scientists have been studying ISHB and testing various control measures since about 2012. Their lessons are now informing efforts in San Jose – where the first case in the Bay Area was detected in November 2023 – and across the region.

“The UC ANR team is comprised of subject-matter experts,” said Drew Raymond, interim agricultural commissioner for Santa Clara County. “The team has compiled all of the experience from the agencies that have been doing work in Southern California and transplanted that experience here to Northern California.”

Lucy Diekmann, UC Cooperative Extension urban agriculture/food systems advisor, and Igor Lacan, UCCE environmental horticulture and urban forestry advisor, have coordinated regular meetings and trainings of Bay Area agricultural officials, land managers and arborists.

“Lucy and Igor have been instrumental in organizing our partners to establish an effective plan for shothole borers,” said Sara Davis, city forester for San Jose. “Because experts across the broader UC ANR network have many years of firsthand experience with this invasive pest, we are able to draw on their practical know-how to guide our monitoring, management and public education efforts.”

Davis is leading a trapping program in San Jose to determine how widespread ISHB is. Aside from a recent detection in the Santa Cruz Mountains, almost all of the approximately 30 confirmed cases in Northern California have been clustered along the riparian corridor of Coyote Creek through downtown San Jose. This pattern of intense but geographically limited damage was also seen across Southern California – notably in San Diego County along the Tijuana River Valley, where ISHB wiped out the willow population.

“I would expect us in the Bay Area to see this type of localized damage that is not fundamentally different from what they're seeing in Southern California,” Lacan said.

Unusually troublesome pest triggers deadly tree disease

The elusive nature of ISHB (with the female seen here next to the smaller male), as well as other aspects of its biology, render typical tools in the integrated pest management toolbox ineffective. Photo by Akif Eskalen, UC Davis

The invasive shothole borers – a term for two species that are virtually indistinguishable, the polyphagous shothole borer and Kuroshio shothole borer – were first detected in Los Angeles in 2003. The tiny beetles, measuring 1.5 to 2 millimeters in length, became a major concern a decade later when swaths of urban forest began dying across LA County.

Infestations are harmful – and fatal for at least 17 tree species in California – because the fungus that the beetle “farms” as its food source causes a disease called Fusarium dieback. Alarmingly, ISHB make their home in a wide variety of trees; Nobua-Behrmann said 65 tree species in California have been identified as “reproductive hosts” where they can grow their populations.

“The fact that they are such a generalist species means that they can find a host almost anywhere,” she said, noting that sycamore, box elder, cottonwoods, oaks and willows are favorites of ISHB.

Furthermore, typical tools in the integrated pest management toolbox are unavailable or ineffective for this invasive beetle. Unlike most insects, these shothole borers mate with their siblings before leaving the tree, so they don't need to search for mates afterward. This means they are not attracted to the pheromone traps typically used for pest control; traps used for ISHB only work to track their numbers, not reduce them.

“Their biology limits what we can do,” Nobua-Behrmann said. “Since the beetles spend most of their lives inside the trees, it's also hard to reach them with insecticides.”

Largely hidden within trees, ISHB can build up their numbers, undetected for years. A tree with green and plentiful leaves may in fact be harboring a significant infestation. “It's easy for this beetle go under the radar and create a big population and a big problem before you even notice,” Nobua-Behrmann said.

Female ISHB create "galleries," the tunnels within which the beetles spend most of their lives, as seen in this sycamore branch. Photo by Beatriz Nobua-Behrmann

Monitoring and early identification of infestations are crucial

Given this pest's elusive nature, monitoring and early intervention have proven to be essential in Southern California.

“All of the success stories have a major component of monitoring and detection; if you have a good monitoring program and you can quickly identify the trees that are infested, timely action can make a big difference,” said Nobua-Behrmann, citing Disneyland in Anaheim as one example where frequent surveys and robust monitoring prevented major impacts.

As most municipalities don't have the abundant resources of a world-famous theme park, Nobua-Behrmann pioneered a program in Southern California to train community members on recognizing telltale signs of the beetle. Specifically, they looked for its entry holes, which have a characteristically round shape and size, comparable to the tip of a ballpoint pen.

Beginning with UC Master Gardeners and UC California Naturalists and then members of the general public in LA and Orange counties (and later other SoCal counties), the program trained about 100 people on how to look out for the beetle. After verification by experts, volunteers were found to be nearly 90% accurate in identifying ISHB.

Although the volunteer monitoring program is on hiatus, Nobua-Behrmann said it had clear benefits that could potentially help other regions. “It would be great to get this program going in Northern California and hopefully get volunteers and people in the general public to help identify infestations there as well,” she said.

Randall Oliver, statewide ISHB communications coordinator for UC IPM, has been instrumental in educating key organizations and the general public about the beetle. Here, he shares information about invasive tree pests at the recent League of California Cities Annual Conference. Photo by Dahmoon Maeesomy, CDFA

Statewide ISHB network spreads essential information

In addition to coordinating an in-person public training in San Jose in April, Lacan and Diekmann, the UC Cooperative Extension advisors, have been educating local UC Master Gardeners on how to spot signs of the invasive beetle.

For about a decade, Lacan has been warning people about the possibility of ISHB in Northern California, routinely including shothole borers in his presentations on “tree pests to watch.” “I've been doing this since before ‘day zero,' but there was not a whole lot of interest in ISHB, as you might imagine,” Lacan recalled. “But then all of that changed in fall of last year.”

In the past year, Lacan has done a dozen ISHB presentations, workshops and webinars, attended by a total of about 260 people – predominantly city foresters, land managers, production arborists and members of tree-related nonprofits.

The significant branch dieback is a sign of a severe ISHB infestation in this sycamore, one of 17 tree species in California for which ISHB-Fusarium dieback complex can be fatal. Photo by Beatriz Nobua-Behrmann

Lacan noted that the most effective presentations have been at in-person events featuring UC ANR-affiliated experts such as Nobua-Behrmann, UCCE environmental horticulture advisor emeritus John Kabashima, and ISHB program staff Randall Oliver and Hannah Vasilis.

“Here is where we tap into our network,” Lacan said. “This is the power of the statewide shothole borers program.”

Another vital asset has been the collection of practical resources gathered by the ISHB program, the UC Integrated Pest Management team and partner organizations. One example is a deck of identification cards depicting how symptoms of infestation differ from species to species. Such detailed information can help managers determine whether a tree is truly infested – and thus allocate their limited resources more judiciously.

“These very specific, very seriously considered materials are the kind of thing that people really appreciate,” Lacan said. “It's not just a generic ‘it's kind of like this.'”

The symptoms, broken down by tree species, are also listed on the ISHB website. Raymond, the interim agricultural commissioner for Santa Clara County, said his team uses the website to get informed about ISHB and regularly refers community members to it.

“The ISHB website has been a great resource,” Raymond said. “It's full of important and user-friendly information.”

Communities learn to protect trees, adapt to shothole borers

If community members believe a tree is infested, they should review the symptoms of ISHB-Fusarium dieback. If the signs match what they are seeing, they should take a photo of the entry hole (with the tip of a ballpoint pen placed next to the hole as reference) and send images to their county agricultural commissioner's office or local UCCE advisor, who may then seek confirmation.

Extra eyes on urban forests are crucial to help experts identify potential “amplifier trees” – heavily infested trees, with more than 150 entry holes, that are often repeatedly reinfested by subsequent generations of beetles. They contribute to the recurring pattern of severe but localized infestations seen across Southern California – and now in San Jose.

When sharing a photo of a suspected ISHB entry hole, it's a good idea to include the tip of a ballpoint pen in the photo as reference. Photo by Monica Dimson, UCCE

New research suggests that removing severely infested trees – or just the most impacted limbs of those trees – can significantly lower the overall ISHB population and help less-infested trees in the area recover over time.

“You're not going to eradicate ISHB (at least not in Southern California); you're not going to get rid of them – you're going to have them forever,” Nobua-Behrmann said. “But you can keep them at a manageable amount.”

She also emphasized other actions the public can take to prevent the spread of ISHB, such as correctly disposing infested plant material – ideally chipping it to less than an inch in length (or as small as possible) and then composting the chips.

“It's also important to not move firewood and instead buy it where you will be burning,” Nobua-Behrmann said. “It's one of the best things people can do to protect trees from invasive pests.”

After identifying and removing amplifier trees, land managers and landscape arborists should have a plan for replanting, Lacan added. He said they should prioritize species that are less susceptible to the beetle, using his Pest Vulnerability Matrix tool that lists the major pests for different mixes of trees.

“We need to figure out how to have sustainable urban forests, even with this pest,” he said. “We know we can do it, largely thanks to our colleagues in Southern California. So the key lesson is to replant soon – choose smartly, but replant right away.”

Posted on Tuesday, October 29, 2024 at 7:00 AM
Focus Area Tags: Environment, Natural Resources, Pest Management, Yard & Garden

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