- Author: Mike Hsu
During summer swarming season, homeowners urged to check for signs of Formosan subterranean termite
In the lottery of troublesome termite infestations, “Roger,” a Rancho Santa Fe homeowner, hit the jackpot (a pseudonym is used to protect his privacy). In 2021, his house in San Diego County was identified as home to only the fourth documented colony of the Formosan subterranean termite (Coptotermes formosanus) in California.
“FST is one of the most destructive urban pests in the world,” said University of California, Riverside entomologist Chow-Yang Lee, affiliated with UC Agriculture and Natural Resources through the campus' Agricultural Experiment Station. “It's also the only termite species listed in the ‘100 of the World's Worst Invasive Alien Species.'”
Endemic to East Asia, this termite is now established in many tropical and subtropical regions, including across the American South. Annually, its infestation costs more than $4 billion in control measures and damage repairs of structures in the U.S.
FST was first discovered in California in La Mesa (San Diego County) in 1992, and it was rediscovered in that city in 2018. Another infestation was reported in Canyon Lake (Riverside County) in 2020. And then, the following year, Roger received his surprise.
“Imagine being in your kitchen looking at your drywall and it's totally normal and then the next day there's a four-inch hole there and you're like ‘What the heck is that? Who put their elbow into the drywall?'” he recalled.
FST colonies can reach millions of individuals
Roger hired a pest control company, Green Flash Pest Control, which sprayed a powerful liquid termiticide in the soil around the house. But the termites – workers, soldiers and winged “alates” – continued to appear. The company tried a second application of soil treatment. But, again, the termites kept popping up.
“We were deeply concerned about the potential damage these termites could cause to the home since these invasive termites are extremely destructive,” said Eric Veronick, director of operations at Green Flash. “Unfortunately, there isn't a whole lot of information available on the behavior and management of this termite in California.”
The company called upon Siavash Taravati, a UC Cooperative Extension urban Integrated Pest Management (IPM) advisor based in Riverside.
“Some colonies are aerial, meaning that they are formed above the ground with limited or no connection to the soil – in such cases, soil treatment using contact insecticides may not be very effective in managing these termites,” Taravati said. “Furthermore, contact insecticides usually kill a much smaller portion of the colony when compared to termite baits.”
To make matters worse, once FST is established in an area, there have been no records of successful eradication anywhere in the world, according to Taravati. He added that a major reason why the Formosan subterranean termite is so destructive is the enormous size of their colonies.
“Their colonies can reach millions of individuals, versus most native subterranean species that reach a few hundred thousand individual termites per colony,” Taravati explained.
This termite, through its sheer numbers, can turn the wood in a structure into a “spongy kind of cake,” in Taravati's words. More than 10 pounds of wood in a house can be eaten by a mature colony each month. The financial hit for a homeowner can be substantial, up to tens of thousands of dollars – not to mention the increased risks to safety.
“Anything from studs to rafters to door frames and window frames – everything is going to be compromised, if the termites are left unchecked. And then, as soon as we have a major stress on the building, let's say there's a big storm or an earthquake – there's a high risk of at least part of the building collapsing,” said Taravati, who also noted that, unlike California native subterranean termite species, FST can attack and kill live trees and plants.
“These termites can be a nightmare,” he said.
Summer is ‘swarming season' for FST
Since the Rancho Santa Fe case in 2021, four more colonies have been documented, in La Mesa again and also in Highland Park, Hollywood Hills and La Verne (the latter three in Los Angeles County). Taravati said it's possible that FST has been spreading via structural lumber or potted plants and soil.
And even if a colony appears to be eliminated at a certain locale, Taravati noted, there is always the chance that part of the colony survives or more colonies of termites already have been established in nearby locations, as a result of swarming termites from the originally infested property.
Although nominally “subterranean,” certain members of an FST colony grow wings and fly to nearby locations to establish new colonies. These winged alates are also called swarmers because of their behavior during the “swarming” season, when termites mate and reproduce.
For the Formosan subterranean termite, that swarming season in California is late May through early August, so now is the time for homeowners and building managers in southern and central California to keep an eye out for those winged termites.
“If you experience a termite swarm in your house, contact a pest management professional and keep some termite samples in a Ziploc bag in the event you need to send the samples to UC Riverside for morphological and DNA-based identifications,” said Lee, who added that it's a good idea to periodically check your structure for signs of infestation, such as wood damage or shelter tubes (mud tubes).
Lee said FST swarmers have a lighter colored body compared to the dark color of native subterranean termites and the orange-brown body of drywood termite swarmers (see this flyer for additional identification information).
Following an especially wet winter, there's a chance California could see more FST infestations, as this termite generally requires moist environments to thrive, Lee added. He recommends that concerned community members seek professional advice.
“Do not attempt to control an FST infestation by yourself,” Lee said. “This is not your typical native Californian subterranean termite species; they are highly destructive, and you want to intercept the problem with the right strategy before it's too late.”
Homeowner: ‘I owe them my house'
In Roger's case, Taravati enlisted the help of Lee and his UC colleague, Greg Kund. They made multiple visits to inspect the home and analyze the situation – going “above and beyond,” according to Roger.
At Lee's suggestion, they used a caulk gun to insert a gel-like experimental bait into the wall where the termites were coming out. Once spread and passed on to the other nestmates, the product – which contains a chitin synthesis inhibitor (a type of insect growth regulator) – interrupts the termites' development so they are unable to properly molt and replace the short-lived “workforce” of foragers and soldiers. The colony eventually collapses and is eliminated.
“Generally speaking, IGRs are much more effective, but they require more patience,” Taravati explained. “You're not going to see the results the next day, or two-three days. You're going to see the results in a few weeks – but when you see the results, it's massive.”
And that's exactly what Roger and Green Flash Pest Control saw.
“Soon after their bait application, the termites stopped emerging from the walls and that gave us and the homeowner a big sigh of relief,” Veronick said. “I appreciate their expertise and dedication in helping us get rid of this destructive pest."
Roger said he is immensely grateful to the UC team.
“They were fantastic; I owe them my house,” he said. “They were super gracious and helpful and responsive and – ultimately, the thing I care most about – they were effective; they fixed the problem. Here we are two years later and – knock on wood, or maybe I should knock on something else! – everything is good.”
Lee also credited Taravati for bringing his knowledge and “can-do” attitude to communities across Southern California.
“He is highly knowledgeable and always able to come up with feasible solutions,” Lee said. “We need good Cooperative Extension urban IPM advisors like Siavash who could provide good advice and bring solutions to the stakeholders, be they homeowners or pest management professionals.”
Taravati said community members need to maintain their vigilance and urges them to download and share the FST flyer that includes identification tips and contact information. He said they are always free to e-mail him with their concerns and photos of suspected FST – not only to help stop the spread of the pest but to expand scientific understanding.
“This termite is so new to California – even for us, as researchers. Despite being in La Mesa since the 1990s, it wasn't until 2020 when these termites were detected in other places, including Riverside and Los Angeles counties,” Taravati explained. “All of us need to learn more about this pest and closely monitor the behavior of this pest.”
/h3>/h3>/h3>/h3>- Author: Saoimanu Sope
Besides starting fires for the sake of research, Luca Carmignani, UC Cooperative Extension fire advisor for San Diego, Orange, Los Angeles, and Riverside counties, has started leveraging his connection to local UC campuses by providing opportunities for hands-on learning.
Early one morning in May, students and staff from UC Irvine and UC Riverside gathered at the South Coast Research and Extension Center to collect data for their own research projects. South Coast REC, located in Irvine, is part of a statewide network of research and education facilities operated by UC Agriculture and Natural Resources.
In one area of the field, graduate students picked leaves and twigs from dried shrubs, carefully placing them in a device that measures moisture content. In another area, a postdoctoral scholar set up a device that records levels of particulate matter, carbon dioxide and other air pollutants emitted by a fire.
Tirtha Banerjee, professor in the Department of Civil and Environmental Engineering at UC Irvine, coordinated the field day with Carmignani. The two first connected as members of iFireNet, an international network of networks that connect people to fire research, when Carmignani was a postdoctoral researcher at UC Berkeley.
Now, the two are collaborating to help environmental science and engineering students realize the potential of their research interests.
Jacquelynn Nguyen, a Ph.D. student in the Civil and Environmental Engineering department at UC Irvine, is interested in understanding how ash from wildfires and prescribed burns can be used as a treatment for per- and polyfluorinated substances. PFAS are a group of “forever chemicals” that can be found in heat-resistant materials – including fire extinguisher foam – and are extremely difficult to eliminate.
Before Nguyen could collect her ash samples, Carmignani needed to cautiously set the dried shrubs on fire, providing a realistic situation for data collection purposes.
“We're trying to figure out if the ashes from these fires can be used as activated carbon, which could be used as a treatment for PFAS,” said Nguyen. “We want to see if this treatment can basically absorb PFAS and prevent it from traveling into soil and groundwater.”
While Nguyen is concerned about the impact that wildfires have on the land, Soroush Neyestani, a postdoctoral scholar in the Environmental Sciences department at UC Riverside, is interested in its impact on the air quality.
During a fire, it's difficult to determine how much emissions are a result of flames versus smoldering, the process of burning slowly with smoke but no flames, and current air quality models do not provide accurate guidance on this matter. Using an air quality sensor, Neyestani wants to quantify the difference in emission levels during the two phases.
“There are assumptions that 50% of emissions come from smoldering, but every fire is different. Our main objective is to improve the accuracy of air-quality forecasting,” Neyestani said, noting his concern that these assumptions might not be realistic.
Although the field day was created with the students in mind, Carmignani used the opportunity to polish his own research efforts. Since fall 2022, he has been investigating the flammability of low-water use landscape plants based on various irrigation applications.
“Every time we burn, I feel like we get better. We get better data, and we conduct better analysis, and that's really important for us so that we can figure out how we can apply our research and measure its outcome,” said Carmignani.
In addition to welcoming more collaborations with UC campuses and other organizations, Carmignani is hopeful that these combined research efforts will spark an interest in wildfire awareness everywhere.
- Author: Mike Hsu
After harvesting and cooking their produce, students ask for seconds of kale
How do you get notoriously finicky sixth graders to eat their leafy greens? Have them grow the vegetables themselves.
Students in Riverside have that unique opportunity through a hands-on gardening and nutrition class at Ysmael Villegas Middle School, with help from CalFresh Healthy Living, University of California Cooperative Extension Riverside County (a part of UC Agriculture and Natural Resources).
“We have middle schoolers asking for seconds and thirds of kale – that's not something that's typical!” said Claudia Carlos, program supervisor for CalFresh Healthy Living, UCCE Riverside, which implements SNAP-Ed locally (the educational arm of the Supplemental Nutrition Assistance Program, formerly known as food stamps).
Growing and tending kale, mint and snap peas in two wheelbarrow gardens on the Villegas campus, the second cohort of students capped their 12-week class with a cooking lesson. A simple recipe combining their kale with tomatoes, onions and coconut milk was a big hit.
“It's one thing to tell youth they should eat healthy, but not until they actually grow the food do they actually take a lot of pride in that food they've grown and harvested,” Carlos explained.
By the end of this school year, about 75 students (in three cohorts) will have taken the class, during which they explore career pathways in gardening, agriculture and nutrition – while cultivating new skills and healthy habits such as choosing nutritious snacks and incorporating exercise into their day. Techniques developed by the UC help encourage effective behavior change.
“In this exploratory class, I've learned how to plant, and take care of plants,” wrote one student, in evaluating the class. “I can use these skills later on in life most likely, and I also learned how to be more healthy.”
Teachers observed that other students also have taken steps to apply their new skills and knowledge.
“They become more confident in themselves and their abilities to make healthy choices for themselves and their families – and to advocate for their parents to buy that kale and actually eat it,” said Daisy Valdez, community education specialist for CalFresh Healthy Living, UCCE Riverside, who is helping teach the class.
Valdez also has been training Villegas teacher Kim Weiss, so that Weiss – a first-year full-time teacher – is empowered to teach future cohorts. Both Valdez and Weiss noticed that nearly all of the youth have been enthusiastic about getting their hands in the soil, watering and weeding regularly – even taking care of the “worm hotel.”
“Students are very invested in the plants, how they are doing and their well-being,” Weiss said. “They ask if they can come back to the class and help care for the plants and worms; students worry about who will take care of the plants and worms after they leave.”
In addition to basic gardening and cooking skills, the class also incorporates lessons about herbs and spices, beneficial insects and pollinators, and cultural dimensions of food. The kale cooking lesson, which recently took place during Black History Month, presented a chance to teach about African food and culinary traditions.
“It allows them to not just connect to the garden but also to connect to their peers and to connect to the world around them,” said Valdez, who added that the garden, planted in a pair of cheerful red wheelbarrows, also beautifies the campus and sparks conversations among their schoolmates about food systems.
The Villegas partnership with CalFresh Healthy Living, UCCE Riverside also benefits the entire school in other ways, with programs reaching hundreds of students and community members. In spring 2021, under Valdez's supervision, students created a “food access board” that shows how to obtain healthy and affordable food through CalFresh EBT, farmers markets, WIC and other resources.
The board, which has been set up in the library, cafeteria and lobby, is seen and used by students and family members. Valdez also engaged parents and the broader community by hosting gardening and nutrition workshops.
This year, Villegas students will have the opportunity to further deepen their cultural connections through a new Youth Participatory Action Research project, in which they explore their personal and family histories through the lens of a meaningful and healthy food item, practice or tradition. Youth will then share their findings with school peers and administrators.
As Carlos noted, these young people will not forget such engaging and immersive experiences with food any time soon. In their evaluations, many students wrote that they learned valuable lessons about compost, care for plants and insects, and healthy eating.
And, as one sixth grader said: “I also learned that kale and coconut milk is amazing!”