Posts Tagged: integrated pest management

Cooperative Extension advisor, UC experts tackle ‘nightmare’ termite

The Formosan subterranean termite is "one of the most destructive urban pests in the world," according to University of California, Riverside entomologist Chow-Yang Lee. Photo by Siavash Taravati

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.

Through its sheer numbers, this termite can turn wood into a "spongy kind of cake," says Siavash Taravati, UC Cooperative Extension urban Integrated Pest Management advisor. Photo by Siavash Taravati

“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.

For FST, swarming season in California is late May through early August, so now is the time for homeowners in southern and central California to keep an eye out for those winged termites, seen here dead along a window sill. Photo by Siavash Taravati

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).

Experts encourage community members in southern and central California to share and circulate this flyer, which includes tips on identifying the Formosan subterranean termite.

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.” 

One strategy is to use an "insect growth regulator" that interrupts the colony's development of workers, soldiers and winged "swarmers", seen here together. Photo by Siavash Taravati

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.”

New online pesticide-use course aims to protect water quality

Animated character guides learners through new UC IPM online course and explains how pesticide runoff enters storm drains and leads to surface water.

Do you know that some pesticides used around homes and other structures are toxic to small aquatic organisms living in nearby streams, creeks, rivers and oceans? The UC Statewide Integrated Pest Management Program has launched a new online course on runoff and surface water protection in California. This course is designed for pest management professionals working primarily in structural pest control or landscape maintenance, but residents and property managers may also find the presented information useful.

Developed by pest management experts from the California Department of Pesticide Regulation (DPR) and the University of California, this course presents information on the Surface Water Protection Regulations that are found in Title 3 of the California Code of Regulations. These regulations were put into place to prevent pesticide runoff into California waterways and to reduce surface water contamination from pyrethroid insecticide use.

In this course, you will learn about the types of pesticide applications that are allowed under the regulations, as well as application types that are prohibited and also application types that are exempt. The course takes a close look at pyrethroids, particularly bifenthrin because of its high use in urban areas, high detection in surface waters, and high toxicity to aquatic organisms. Fipronil, another commonly used ingredient in structural and landscape products, is addressed in the course as well because it causes similar water-quality concerns as pyrethroids. Bifenthrin is used for managing pests such as ants, crickets and lawn grubs. Fipronil is used for ants, roaches and termites.

The Urban Pyrethroid and Fipronil Use: Runoff and Surface Water Protection course has been approved by DPR for a total of 1.5 continuing education units, including 0.5 hour of Pesticide Laws and Regulations and 1.0 hour of Other and by the Structural Pest Control Board for 1.5 hours of Rules and Regulations.

The course takes about 90 minutes to complete. It is divided up into seven sections so a person can stop and resume where they left off. The course is free. To take the course, people need to set up an account at https://campus.extension.org/ then they can enroll. The direct link to the course is https://campus.extension.org/course/view.php?id=2221.

UC IPM currently offers 22 online courses with continuing education units from DPR. Many of these courses are also credited by the California Structural Pest Control Board, Certified Crop Adviser, the Western Chapter of the International Society of Arboriculture, and the Arizona Department of Agriculture.

Residues from urban pesticide applications may be washed into storm drains and lead directly into creeks, rivers, and oceans. Credit: Petr Kosina, UC IPM

Screen from the surface water protection online course showing buttons a learner can click on to learn about regulated applications to various surfaces.

More detail, key updates in new edition of pesticide safety manual

More than just a study guide, the manual provides information on essential processes and procedures that will help keep applicators safe – as well as reduce environmental impacts from misapplication.

Publication in English, Spanish prepares private applicators for state exam

Expanded from four chapters in the previous edition to 12, the third edition of Pesticide Safety: A Study Manual for Private Applicators aims to be more than just a study guide.

The manual, available for purchase in English and Spanish, provides much more detail on essential processes and procedures that will help keep applicators safe while using pesticides – as well as reduce environmental impacts from misapplication.

Published by University of California Agriculture and Natural Resources in collaboration with the state's Department of Pesticide Regulation, the manual – intended for members of the agricultural community who own, manage or work on farms that use restricted-use pesticides – also includes substantial updates.

 “The information in the book they were using was way out of date,” said writer/editor Shannah Whithaus, senior editor for pesticide safety education with UC ANR's Statewide Integrated Pest Management Program. “Also, the book was much, much shorter than it needed to be, because it wasn't providing enough information for people to safely apply pesticides, given the complexity of the regulatory environment we're in now.”

The new edition features a more user-friendly layout that clearly highlights key learning objectives.

The new manual reflects important changes to federal and state regulations since the publication of the previous edition in 2006.

“There are significant regulatory updates which help you stay up-to-date with safety rules and standards – and protect your workers from overexposure to pesticides,” said Lisa Blecker, technical editor of the publication, and currently a pesticide safety educator at Colorado State University.

In addition to emphasizing the broader ecological ramifications of improper pesticide use, the manual includes information on subjects that might get short shrift in other manuals, such as the correct calibration of equipment to ensure accuracy of application.

“All of that is now in the book and fully fleshed out,” Whithaus said. “[Applicators] are going to be able to do that much more effectively using the new book, compared to the old one – it was really hard to be thorough in 80-some pages.”

The new edition – totaling more than 200 substantive pages – also features a more streamlined and user-friendly layout modeled after a sister publication, The Safe and Effective Use of Pesticides, written for commercial applicators.

“A significant update is a layout that is not only beautiful, but helps you identify key information you need to know in order to make safe and effective pesticide applications,” Blecker explained.

She highlighted the “knowledge expectations” listed at the beginning of each chapter and in the margins of the book, next to the relevant passages. The statements serve as “visual cues” to help readers learn and retain the material they need to pass California DPR's certification exam for private applicators.

And while the manual functions as an improved study aid for owners, managers and workers who apply pesticides, it doubles as a reference that they can turn to for years to come.

“It's going to be able to serve as a reference manual, as opposed to just a study guide,” Whithaus said. “You really will be able to use this book as a tool to help you do better in managing your land.”

The manual, listed at $29, is available for purchase in English at https://anrcatalog.ucanr.edu/Details.aspx?itemNo=3383 and in Spanish at https://anrcatalog.ucanr.edu/Details.aspx?itemNo=3394.

UC explores alternatives to fumigants for strawberries

Soilborne diseases reduce strawberry yields and eventually kill infected plants. Photos by Joji Muramoto

Strawberries, which generated $2.2 billion for California growers mainly on the coast in 2019, are sensitive to soilborne diseases. Strawberry plant roots infected by fungi are unable to take in nutrients and water, causing the leaves and stems to wilt. The diseases reduce fruit yields and eventually kill infected plants.

To protect the delicate plants from pathogens, strawberry growers fumigate the soil with pesticides such as chloropicrin and 1,3-dichloropropene before planting transplants. Due to the potential negative effects on the environment and human health, however, use of fumigants are highly regulated and developing non-fumigant alternatives has been a priority of the strawberry industry.

For a biological alternative to manage soilborne diseases in strawberries, Joji Muramoto, UC Cooperative Extension organic production specialist based at UC Santa Cruz, has received a $411,395 grant from USDA National Institute of Food and Agriculture to study the ability of other crops to suppress strawberry pathogens in the soil.

Strawberry plants infected with a. Verticillium wilt, b. Fusarium wilt, and c. charcoal rot. These symptoms are very similar to each other and are difficult to diagnose visually.

Verticillium wilt, caused by Verticillium dahliae, is a common soilborne disease that can be controlled with anaerobic soil disinfestation (ASD), a fermentation-based biological treatment using carbon sources such as rice bran under plastic mulch in moist soils for 3 to 5 weeks in autumn. About 2,000 acres of berry fields, mostly organic, were treated with ASD in California and Baja California, Mexico, in 2019.

In 2008-09, the diseases fusarium wilt, caused by Fusarium oxysporum f. sp. fragariae, and charcoal rot, caused by Macrophomina phaseolina, emerged in Southern California and now threaten strawberry plants throughout the state. 

ASD isn't as effective against F. oxysporum and M. phaseolina unless it is applied in summer on the coast. As saprophytes, they feed not only on living plants, but also can colonize crop residues and rice bran especially at lower coastal temperatures in autumn. Treating fields on California's coast with ASD during summer is difficult because it competes with the vegetable production period.

Charcoal rot symptoms can resemble other soilborne diseases so it is essential to identify the pathogen using molecular approaches. Photo by Joji Muramoto

Based on promising studies in Asia and other areas, Muramoto plans to test alliums – such as onion, bunch onion and leek – and a certain variety of wheat (Summit 515) to see if they will suppress F. oxysporum and M. phaseolina. His team will conduct a series of greenhouse and field trials and test these crops with and without ASD to compare the effects on soilborne pathogens.

“Studies have shown the potential of using allium crops to control Fusarium wilt, and Summit 515 wheat for charcoal rot,” Muramoto said. “Our goal is to examine the effectiveness of suppressive crops, optimize them for California strawberry production systems, and evaluate their economic feasibility for commercial use.”

“No single tactic is likely to replace fumigants,” he said. “Integration of multiple biological approaches such as crop rotation, ASD, and use of resistant strawberry varieties is a key to develop a successful non-fumigant-based soilborne disease management strategy for strawberries. This project is a part of such broader efforts.”

The process of anaerobic soil disinfestation (ASD): a) Broadcast rice bran at a rate of 6 to 9 tons/acre to feed indigenous soil microbes. b) Incorporate rice bran into the soil. c) List beds. d) Lay drip tapes and cover beds with plastic mulch as soon as the incorporation is completed. e) Saturate and then maintain field capacity soil moisture for three weeks. f) Monitor soil redox potential and apply additional water when the soil is becoming aerobic.

At the end of the three-year study, he plans to share the results at workshops, field days and webinars.

Rachael Goodhue, UC Davis professor of agricultural economics; Carol Shennan, UC Santa Cruz professor of environmental studies; and Peter Henry, USDA Agricultural Research Service plant pathologist, are co-principal investigators on the study with Muramoto.

Also collaborating on the project are Christopher Greer, UC Cooperative Extension integrated pest management area advisor in San Luis Obispo County; Oleg Daugovish, UCCE vegetable and strawberry advisor in Ventura County; Mark Bolda, UCCE director strawberry and cane berry advisor in Santa Cruz County; Jan Perez, food systems specialist, and Darryl Wong, farm research manager, at UC Santa Cruz Center for Agroecology and Sustainable Food Systems; Miguel Ramos of Ramos Farm; Agriculture and Land-Based Association (ALBA); Driscoll's; Naturipe; and The Oppenheimer Group.

Controlling ants the healthy way

To help control ants inside, wipe them up, along with their chemical trails, with an all-purpose cleaner, and fill tiny gaps, cracks and holes with caulk to make their entry difficult.

Spotting ants in the home or yard is no reason to reach for insecticide sprays or call an exterminator. UC Cooperative Extension experts say the insects can be managed by residents in ways that are effective, inexpensive, safe and environmentally kind.

“Ants are probably the No. 1 most common pests of our homes and gardens,” said Carolyn Kinnon, an environmental horticulturist and instructional associate at Mira Costa Community College. “Scientists find chemicals in our waterways that include pesticides commonly used to kill ants.”

Kinnon teamed up with UCCE community education specialist Scott Parker to present a Healthy Garden-Healthy Home online ant workshop during the COVID-19 pandemic to take the place of a planned in-person event. Healthy Garden-Healthy Home was initiated in 2005 with a grant from the California State Water Resources Control Board and continues with funding from San Diego County. With the move online, the workshop attracted four times more participants that usual.

“A silver lining of the COVID disaster has been our ability to reach out to many more individuals,” Parker said.

Healthy Gardens-Healthy Homes aims to cut residents' use of chemicals and reduce soil erosion that can wash into gutters with irrigation or rain water, course through storm drains and into streams, reservoirs and the Pacific Ocean. During the recent UCCE webinar on healthy ant control, Kinnon introduced science-based solutions that can be combined to keep ants at bay.

Use ant biology to battle ants

Ants are always looking for food and will forage any accessible source. Short circuiting this biological need is the first approach to controlling the pest. Outside, ants are often attracted to a sticky, sweet honeydew that pests like aphids leave behind when they feed on plants. Washing off aphids and honeydew with a sharp stream of water from the hose reduces the food source.

In spring, Kinnon said, ants like to feed on proteins, like seeds, nuts, dog food and other fatty substances. Fallen nuts, bird seed and leftover pet food should be discarded to reduce ant activity.

“When honeydew production from sap-sucking insects declines in the hot summer, and there is an absence of food sources outdoors, ants may come indoors,” she said. “Ants will travel several hundred feet in search for food.”

Removing inside food sources – like spills on counters and floors – and blocking access – by filling in holes and cracks – is the first defense against an indoor ant invasion. Kinnon recommends keeping food containers clean and sealed, rinsing empty recyclables – particularly sugar-sweetened beverages – and wiping up grease on barbecues and stove tops.

Wipe up ants and their chemical trails with an all-purpose cleaner, and fill tiny gaps, cracks and holes with caulk to make their entry difficult.

Managing expectations

Another way to achieve environmentally friendly ant management is coming to terms with the fact that they can't be eliminated from outdoor areas.

“Our goal is to focus on reducing population numbers,” Kinnon said. “We have to tolerate a certain number.”

Spraying a pesticide on an ant trail or sprinkling granular pesticides will only kill a fraction of the ants in the yard. Those materials can run off and pollute watersheds.

Baits

If cleaning up food sources, exclusionary measures and increased tolerance aren't enough, pesticide baits are an additional integrated pest management tool.

“This works because female worker ants take the bait back to the nest and feed it to other ants in the colony,” Kinnon said.

The bait must be slow acting so it doesn't kill the worker before she gets back to the colony. Kinnon recommended baits with no more than .5% active ingredient. For best bait placement, follow trails to find the nest and place the bait close by in a safe bait station. If the nest can't be found, the bait station can be placed along the trail.

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