- 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.
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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: Help Desk Team
This year was particularly bad for peach leaf curl and other fungal infections in fruit trees because of the wonderful rain we had last winter and spring. It looks like we might have another wet winter, so we are rerunning this post to remind you to think about a spray program for your trees.
Now that the leaves have fallen, or mostly fallen, from your backyard fruit trees, are you wondering whether you should apply dormant sprays?
“Dormant sprays” or “delayed dormant sprays” are terms used for the application of pesticides when the tree is dormant or just coming into bud swell. The pesticide could be a fungicide used to help manage fungal disease or a horticultural oil or oil in combination with insecticides to kill insects.
Don't assume that you need dormant spray. Before reaching for the spray, first determine whether your trees have previously had a disease or serious insect pest problem that can be managed with dormant sprays. Have you already tried all non-chemical recommendations for lessening the problem? Finally, evaluate the amount of damage from the disease or insect pest you experienced in the prior growing season to decide whether a pesticide is really needed.
Fruit tree diseases that can be managed by applying a fungicide dormant spray include peach leaf curl, brown rot, and shot hole disease.
Peach Leaf Curl
Peach leaf curl affects only peach and nectarine trees. It shows up in spring after the tree has leafed out. Leaves are thickened, curled, and colored red or yellow instead of normal green.
If your tree has had significant peach leaf curl in prior years, dormant spraying with a fixed copper spray just after all the leaves have fallen from the tree (usually December to January in our County) may prevent or reduce the severity of the disease. For information on managing peach leaf curl, see https://ipm.ucanr.edu/PMG/PESTNOTES/pn7426.html/
Brown Rot
Brown rot (Monilinia) is a fungal disease that can affect peaches, plum, cherries, apricots, and nectarines. In the spring blossoms on infected trees shrivel and die, often clinging to the twigs. Leaves at the base of infected twigs may also turn brown and die. Fungal spores attach themselves to developing fruit and show up as brown or tan spots on the surface of the fruit.
If your trees had significant fruit loss from brown rot in the prior growing season, a dormant spray of a copper-based fungicide may help. Apply it at the pink bud stage while flower buds are still tightly curled and pink in color. For more information on brown rot, see http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/DISEASE/aprbrownrot.html.
Shot Hole
Shot hole (Coryneum blight) can affect plums, nectarines, peaches, cherries, and especially apricots. It shows up as small reddish holes on leaf surfaces. Often the holes turn brown and drop out. Fruits may also be infected. Where disease has been severe and cultural steps haven't helped, a fungicide spray following complete leaf drop may be needed. See http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/DISEASE/shothole.html.
Brown Soft Scale
Insects that can be managed with dormant sprays of horticultural oils or oils mixed with insecticides include scale, aphids, and spider mites. Don't spray unless you have confirmed that the insects are present in damaging numbers and cannot be controlled by other means. Keep in mind that spraying may also kill beneficial insects which are the first line of defense against insect pests. More information on controlling these insect pests can be found at these UC websites: http://ipm.ucanr.edu/QT/scalescard.html, http://ipm.ucanr.edu/QT/aphidscard.html and http://ipm.ucanr.edu/QT/spidermitescard.html.
Caution: Before spraying, read and carefully follow the label instructions on the pesticides you use, including wearing recommended protective gear.
Help Desk of UC Master Gardener Program of Contra Costa County (TKL)
- Author: Jeannette Warnert
Early morning birdsong, hummers darting around flowers and tiny doves in patio nests are enchanting. Without the farmers' concern about profit, gardeners can more readily forgive the occasional pecked fruit, stolen nuts and avian grazing on freshly planted vegetable seeds.
UC Cooperative Extension human-wildlife interaction advisor Breanna Martinico said during a webinar presentation that integrated pest management techniques can be used to maximize bird benefits while minimizing the damage they can cause.
She suggests starting with identification.
“Bird ID is fun,” she said. “Sit in the backyard with a cup of coffee, binoculars and a bird ID guide and get to know what birds are using your backyard. It's a great way to relax and connect with nature. You might be surprised what you find that you weren't noticing before.”
If birds are causing a problem, cultural practices – such as exclusion with netting or frightening with bird distress calls or fake predators – are more effective than control. “Be sure to include a cost-benefit analysis when deciding on bird deterrents or exclusion,” she said. “It may be best to tolerate damage if it is minimal.”
Lethal control is strictly regulated and rarely the best choice. Many birds in the U.S. are protected under the Federal Migratory Bird Treaty Act. It is illegal to kill or capture migratory birds or destroy their eggs or nests. Game bird hunting is regulated by the California Department of Fish and Wildlife and limited by location and hunting seasons.
Martinico's talk was more focused on supporting bird populations by making gardens welcoming to birds, and gaining an appreciation for the beneficial role bird species play in California.
She shared the results of recent research on Western bluebirds and songbirds that used forensic DNA analysis of droppings to determine exactly what birds are eating.
“They eat incredible amounts of insects,” Martinico said. “If a particular insect is abundant and becoming a pest, they are effective at reducing pest numbers.”
Sometimes birds that have a reputation for eating desired crops only do this during certain seasons, while at other times they are gardeners' friends. Blackbirds, for example, eat insects in the spring when they need a protein-rich diet to feed their young. They only need to be scared away in late summer, when their flocking behavior becomes more prevalent, and they switch to grains and seeds.
Welcome birds to the garden
Invite birds to your garden by growing diverse, complex landscapes with food and water sources. Large monocultures, like lawns, can have ample resources for pests, but not enough to support other species that might reduce pests, Martinico said. Grow native plants and large trees, and place nest boxes for pest-eating birds like barn owls, ash-throated flycatchers, Western bluebirds, tree swallows and house wrens. Raptor perches will give birds of prey a place to hunt for gophers and other rodents.
When there is bird activity in the backyard, particularly nests with eggs or chicks, minimize the presence of people, cats, dogs, noise and bright lights at night, Martinico said.
Resources:
Birds on home and landscape tree fruit and vines, UC Integrated Pest Management Program
Songbird nest box plans, North Carolina State Extension
Barn owl nest box plans, Wild Farm Alliance
Information about local bird populations, Nestwatch, Cornell Lab of Ornithology
Birds: Friends or Foes? webinar on YouTube
Breanna Martinico, Human-Wildlife Interactions Advisor, Napa, Lake, and Solano counties
