- Author: Lauren Fordyce
Healthy Soils Week (Dec. 4-8) is a week-long initiative by the California Department of Food and Agriculture (CDFA) to highlight the importance of soil health throughout California.
Healthy soils can improve crop yields, sequester carbon, reduce erosion, and increase biodiversity. In addition, they can reduce pest problems and pesticide and fertilizer use. Healthy soils lead to healthy plants which are less susceptible to pest attacks and can better tolerate and recover from pest pressure.
In integrated pest management (IPM) we promote the use of cultural control methods to improve soil and plant health, making an environment less conducive for pests to establish, reproduce, and cause damage.
Here are some cultural tips for creating healthy soils and reducing pests:
- Improve soil drainage to avoid oversaturated, water-logged soils. Moist, compacted soils can attract earwigs, slugs, and nematodes and encourage damping off, Phytophthora, and other diseases to develop.
- Use mulch. Mulches can moderate soil moisture and temperature, reduce compaction, and suppress weeds. But use them carefully as improperly selected or applied mulches can damage plants and attract pests.
- Clean up fallen fruit and leaves. Good sanitation is essential for preventing pests from establishing and spreading. Removing infected fruit, leaves, and branches can prevent insects and pathogens from overwintering in the soil.
- Fertilize appropriately. Too much or not enough nutrients in the soil can result in plant stress. Stressed plants are more susceptible to pests and diseases. Applying too much fertilizer (especially nitrogen) can result in excessive plant growth which often attracts pests like aphids and psyllids.
- Dethatch lawns. Thatch includes pieces of grass stems, roots, and rhizomes. It is slow to decay and can build up on the soil surface making it difficult for water to reach the roots. Several turfgrass pathogens can also survive in thatch.
- Solarize the soil as needed. Soil solarization uses heat from the sun to kill pathogens, nematodes, and weed seeds in the soil.
Healthy soil is the foundation of sustainable pest management and a thriving ecosystem.
- Author: Andrew M Sutherland
Baits Eliminate and Prevent Subterranean Termite Colonies
Subterranean termites (Family Rhinotermitidae) are considered the most serious wood-destroying pests in the world, causing an estimated $32 billion in global economic impact each year. California is home to both native and introduced subterranean termite species (Figure 1). Infestations of wooden structures are widespread and common. Pest control operators (PCOs) have conventionally applied liquid termiticides to control these pests, usually as soil drenches or injections around structures. These treatments may not always be effective, however, especially if good underground coverage is not achieved, if local termite pressure is very high, or if dealing with the invasive Formosan subterranean termite in Southern California. Furthermore, the active ingredients in most liquid termiticides are increasingly monitored by the State as environmental contaminants and may be subject to legal restrictions in the future.
Bait systems for subterranean termites (Figure 2), which employ slow-acting insecticides that kill worker termites by preventing successful molting, may represent effective alternatives to liquid treatments. Baits, deployed within stations installed in the ground or in line with aboveground shelter tubes, have gained popularity during recent decades and are now considered the primary subterranean termite control tactics in many parts of the world. Adoption of bait systems in California has lagged most other regions, however. Reasons PCOs in California have reported being reluctant to use bait systems include 1) time required to achieve control is too long, 2) little efficacy data in California, and 3) the regular monitoring of bait systems is too labor intensive or otherwise does not fit established business models.
Recently, the third “adoption barrier” may have become less important: new product label guidelines allow PCOs to extend inspection intervals up to 12 months and allow for baiting without the previously required monitoring phase (provided the target pest is confirmed at the site). Considering the regular revenue streams created by “controlled service agreements”, where PCOs contract with property owners to prevent and control pests over a long term, these newer labels should drive more widespread use.
Some observations and case studies indicate that, indeed, bait system adoption is now slowly increasing in California. To address the other two reported barriers (speed of control and efficacy), we secured funds from the state's Structural Pest Control Board to evaluate and demonstrate three different in-ground bait systems in the San Francisco Bay Area and the greater Los Angeles area.
Bait Efficacy
Our first objective was to evaluate efficacy at single-family homes. To do this, we collaborated with five different PCO companies who expressed interest in the new business models made possible by the newer bait product labeling guidelines. Some of these companies had experience with baits, while some gained their first experiences through this project. Companies received research stipends to subsidize their participation. Fifteen single-family homes were eventually selected, based on several experimental criteria: 1) documented activity of subterranean termites within 1 meter of the structure, 2) no liquid termiticide application within the previous 5 years, and 3) no significant structural infestations detected during the initial inspection. Participating homes were in Alameda, Contra Costa, Los Angeles, Orange, and Santa Clara counties. Bait stations, baits, service equipment, and, in some cases, training, were provided by manufacturers.
The UC research team and the PCOs installed bait systems according to product labels, usually with one bait station for every 10–20 linear feet of the structural perimeter. Since all 15 sites had confirmed termite activity at the perimeter, all stations installed contained active bait, rather than monitors. The UC research team installed monitoring stations with wooden blocks immediately adjacent to each bait station. The UC team then visited each participating home every 3 months for 2 years, checking termite activity within monitoring stations and collecting termites whenever possible. The PCOs and the UC team visited each participating home every 6 months to check termite activity within bait stations, replenish baits (as per product label), and to collect termites. Collected termite specimens were sent to a collaborating lab for DNA analysis, where each sample was assigned a “Colony ID” based on its genetic signature, distinguishing it from all other colonies. At the end of the 2-year period, a final structural inspection was conducted at each home.
Findings
Most importantly, despite significant termite pressure, none of the 15 homes became infested during the study period. Foraging termites were observed and collected during initial inspections, from wood blocks during quarterly inspections, and from bait matrices during bi-annual inspections with PCOs. In some cases, termites were observed and collected from bait stations only 6 months after installation. 132 separate samples of western subterranean termites (Reticulitermes hesperus species complex) were collected. DNA analysis revealed that many of our research sites included between 3 and 5 unique colonies; 1 property included 15 unique colonies! Bait was consumed at all sites, to varying degrees. No termite colony recovered from bait stations was ever detected again.
These observations strongly suggest that all three studied bait systems were effective at eliminating termite colonies and at preventing structural infestations over a 2-year period. Furthermore, post-project surveys conducted with property owners and PCOs indicated that all parties were satisfied with the services provided and control achieved; several companies new to baiting have now embraced the program we demonstrated as a new service offering for their customers.
Reducing “time-to-attack”
Our second objective in this research project was to investigate factors influencing bait interception time (also called “time-to-attack”). One explanation for lengthy bait interception times in California may be the interaction of climate (hot summers with little to no rain) and soil texture (high proportions of clay). Termite foraging at or near the soil surface may be limited or even nonexistent during summer months, especially when areas are not irrigated. Some research supports this idea: western subterranean termites have been observed to forage near the surface mostly during winter months in Southern California. This suggests that baits installed in summer may sit uninvestigated for 6 months or more. To test this hypothesis, we established five research plots at the UC Berkeley Richmond Field Station directly on top of areas where naturally occurring Reticulitermes termites had been observed or collected. Around these areas, we established 3 concentric rings of bait stations at 3 distances from the center, installing 1 station from each of 3 registered systems (Table 1) along each of the 3 distance rings at the beginning of each season over 1 year, for a total of 36 bait stations per plot. We didn't want to kill the termites in these plots because that would significantly confound our data, so we used cellulose bait matrices from manufacturers that did not contain the active ingredients. We also installed monitoring stations containing wood blocks at the center of each plot and along each of the three distance rings. We then checked each station every 2 months for 2 years, recording bait consumption and termite incidence.
Of the 180 bait stations and 20 monitoring stations installed, 78 bait stations and 9 monitoring stations had been hit by the end of the 2-year project period, representing an overall hit rate of 44%. Three stations were attacked within 60 days after installation, and 10 stations were attacked within 120 days. Overall, however, the average bait interception time was 367 days, supporting the general claims of California's pest control operators that baiting may take too long for most remedial termite control jobs. There were no significant differences between the three bait systems or the three distance rings.
|
Bait System, Manufacturer |
Bait Information |
Installation Specifications (for in-ground use) |
Service Specifications |
|---|---|---|---|
|
Sentricon Always Active, Corteva Agriscience |
Recruit HD Termite Bait (EPA# 62719-608): cellulose tube, 0.5% noviflumuron |
≤ 20 feet intervals; buildings, fences, decking, utility poles, trees |
Inspections at least once annually; replace bait if damaged or ≥ 1/3 consumed |
|
Advance Termite Bait System (ATBS), BASF |
Trelona Compressed Termite Bait (EPA# 499-557): cellulose wafers in plastic housing, 0.5% novaluron |
≤ 20 feet intervals; buildings, trees, wood piles, landscape elements, railroads |
Inspections at least once annually; replace bait if damaged or ≥ ½ consumed |
|
Exterra Termite Baiting System, Ensystex |
Isopthor Termite Bait (EPA# 68850-2): cellulose wafers within burlap sachet, 0.25% diflubenzuron |
≤ 20 feet intervals; buildings and other structures |
Inspections every 45 – 120 d, up to six months allowed; replace bait “after sufficient consumption” |
Our study's main question was whether installation season significantly impacts “time-to-attack” due to seasonal differences in termite foraging in California. To answer this, we pooled data from all five sites and all three bait systems and then considered just the first year of observations. The result was clear: baits installed at the beginning of winter (December 16) were intercepted ~100 days faster than baits installed at the beginning of summer (June 24)!
Conclusions
Bait stations systems may be very useful pest control tactics for use against subterranean termites in California, especially when dealing with very large colonies of native western subterranean termites, multiple colonies, sensitive sites, or sites where liquid treatments have failed. According to the labels of the three products evaluated, systems can be installed with active ingredients present on Day 1, provided a licensed Field Representative has detected and identified the target species at the site. Licensed Applicators may, according to label language and California's Structural Pest Control Act, then service bait stations, replenishing bait that has been consumed or damaged. Two of the systems evaluated allow for annual inspections, while one allows for bi-annual (every 6 months) inspections. Operators in California may decrease the bait interception time, and therefore the perceived early efficacy, by targeting initial installations for the beginning of the wet season.
[Originally featured in the Fall 2023 edition of the Green Bulletin Newsletter for structural and landscape pest professionals.]
It's #GivingTuesday! – a global day of giving that harnesses the collective power of individuals to celebrate generosity.
If you've utilized the extensive UC IPM website and our free publications, watched one of our webinars or videos, read our newsletter, or shared our social media posts on Facebook or Instagram, you've seen how #GivingTuesday donations help produce important information, tools, and trainings that enhance the quality of life, and the environmental and economic well-being of Californians.
We encourage you to support the UC IPM Urban and Community program so we can continue to create and improve the quality of free, sustainable pest management information available to the public. You can learn more about the UC IPM program's goals and impact by reading our strategic plan.
Donate here and select “UC IPM – Urban and Community fund” in the dropdown menu under “Designation”. We appreciate your contribution!
The holiday season is fast approaching! With many people traveling and visiting new places during this time, it's important to understand how to check for bed bugs and prevent them from coming home with you.
Regardless of what type of lodging you choose–hotel, motel, cabin, or other type of rental–no place is immune to bed bug introductions or infestations. Follow these tips for a bed bug-free holiday.
When settling into your room
- Before putting your luggage down on the bed, couch, or floor, do a quick bed bug check. You can either leave the luggage in the hall or place it in the bathtub, where bed bugs are not likely to be.
- Thoroughly inspect the bed, nightstand, upholstered furniture, and closets. You can use a flashlight or a phone light to help you look for bed bugs, shed skins, or fecal spots. Look along mattress seams, under covers, around the box spring, behind headboards and picture frames, and along baseboards.
- Watch this video to learn how to do a bed bug inspection: https://www.youtube.com/watch?v=oWCc3Mngo7E&t=2s
After you return home
- Before bringing luggage inside your home, inspect it for any signs of bed bugs that may have hitched a ride. Store luggage away from the bedroom to prevent potential introductions.
- Launder all the clothes from your trip on the hottest settings to kill bed bugs or their eggs that may have gone unnoticed. For items that cannot be washed, freezing them for several days will also kill all stages of bed bugs.
To learn more about bed bug identification and management, see the UC IPM Pest Notes: Bed Bugs. Staying home for the holidays? Here are some tips to host a bed bug-free holiday!
- Author: Kathy Keatley Garvey
Sometimes overlooked as pollinators are the syrphid flies, also known as "hover flies" or "flower flies."
Unfortunately, they are often mistaken for honey bees. Hey, if it's a critter on a flower, it's a bee, right?
Not necessarily!
Syrphid flies are easily distinguished from honey bees. Among the differences: (1) honey bees don't hover, (2) syrphids have only one pair of wings, while honey bees have two (3) syrphids have short, stubby antennae, while honey bees have long, bent antennae called genticulate antennae and (4) syrphids belong to the order Diptera, while honey bees are in the order Hymenoptera.
We spotted this syprhid fly soaking up some early-morning sun It stayed still for a dorsal photo and then sensing danger, slipped under a leaf.
Scientists estimate that there are more than 6200 species of syrphid flies in the world, and more than 3000 in California alone.
The UC Statewide Integrated Pest Management Program (UC IPM) has this to say about syprhids in its Natural Enemies Gallery post: "Adults are robust to slender flies 1/8 to 1 inch (4–25 mm) long, varying by species. The broad head is about the width of the abdomen or wider and has large eyes with distinct antennae. The body of many adults is black with bands or stripes of orange, yellow, or white, resembling stinging bees or wasps. Some species are mostly brown, metallic blue or green, yellow, or combinations of these or other colors. For example, adults of ant-predaceous Microdon species are blackish to brown or bright to dark greenish."
Many syrphids prey on aphids and mealybugs, so they're good guys and gals to have in your garden.
Says UC IPM: "Most species are predaceous, most commonly on aphids or mealybugs. Some syrphids prey on ants, caterpillars, froghoppers, psyllids, scales, other insects, or mites."
The good guys and gals of the garden...
