- Author: Belinda Messenger-Sikes
During the holiday season, the only creatures you want stirring in your home are your family, friends, and pets. But as temperatures drop, and the rain returns, some pests may seek shelter indoors with you. Rats and mice can be problems all year but in the cold weather, they prefer the warmth of your home to being outdoors and you might see more in your home.
Pests invade homes for varying reasons during autumn and winter. Common outdoor species such as Argentine ants, Oriental (or Turkestan) cockroaches, sowbugs and pillbugs, springtails, and earwigs, may simply be escaping harsh conditions such as freezing temperatures or small-scale flooding. Some insects, especially true bugs (Hemiptera); such as boxelder bug, bordered plant bug, milkweed bug and other seed bugs, false chinch bug, and various stink bugs, naturally seek out dry, protected cracks and crevices to spend the winter. In the landscape, such sites may be beneath loose tree bark or deep within firewood piles, but structural gaps, cracks and crevices may be warmer, drier, and more attractive to these overwintering bugs.
It's generally easier to keep pests out before they become a problem than to try and get rid of them once they infest your home. Exclude pests by sealing up possible entry points around doors, windows, foundations, chimneys, roof joints, shingles, and vents. Install door sweeps and threshold seals to get rid of gaps under and around doors. If you have gaps around windows, you can close them with weather stripping and expanding foam or install new screens.
Clean up the landscape around your home so pests have fewer places to live and breed. Move wood chips and other organic mulches, and firewood piles away from your home's perimeter and entryways. Drain any excess moisture near structural foundations and entryways.
If you spot nuisance pests like boxelder bugs, earwigs, springtails, and centipedes indoors, they can be simply swept up, vacuumed, or taken outside. Other pests like mice and rats need to be dealt with differently.
Ideally, mice and rats should be managed before they get inside. Check the exterior of your home for signs of a mice or rat infestation including droppings, gnaw marks, feeding damage, and rub marks. For mice and rats, tight fitting lids on garbage cans and compost containers will keep these rodents from finding a food source near your home and eventually coming indoors. Thin vegetation between shrubs and buildings and trim back overhanging trees. Roof rats will use climbing vegetation to scale buildings and seek shelter. Seal any cracks or gaps into your home that are larger than 1/4 inch. Screen or block potential entrances under eaves or overlapping roof sections. Use sheet metal or 1/8-inch wire hardware cloth to keep out mice and rats since rodents can gnaw through softer material like plastic or wood.
Snap traps are the safest, most effective, and most economical way to manage rats and mice. You can place traps outside the home to catch rodents before they enter. You can also place them inside if you spot signs of them there. Be sure to use the correct-sized traps and place them in secluded areas along walls, behind objects, in dark corners, and in places where droppings have been found.
Keep pests from ruining your holiday fun by denying them food, water, and shelter in your home. For more details about specific pests and their management, see the UC IPM website https://ipm.ucanr.edu/PMG/menu.homegarden.html.
[Originally featured in the Winter 2023-2024 edition of the Home & Garden Pest Newsletter.]
- Author: Andrew M Sutherland
- Author: Brandon Kitagawa
Multi-unit housing (MUH), such as apartment complexes and single-room occupancy (SRO) buildings, can harbor significant infestations of cockroaches, bed bugs, rodents, and other pests. Structural continuity (shared walls of adjacent units), budgetary constraints, poor maintenance and infrastructure, and cultural and social factors allow pests to infest and thrive in these environments.
Many of these pests threaten public health and wellbeing of the residents. For instance, German cockroaches (Blattella germanica) produce proteins that can be found in their feces and exoskeletons that, when dispersed into the air, can be inhaled, causing asthma in children.
Pest management is often conducted in response to complaints or after discovery of serious problems rather than proactively, especially in low-income communities. Proactive integrated pest management (IPM) programs that include regular monitoring of pests within every residential unit improve building-wide pest control and prevent significant infestations. These programs are labor-intensive, however, especially at the onset, and so may be considered too expensive by property owners and managers.
To show the effectiveness of proactive IPM and to investigate the relationship between cost and pest control, we partnered with affordable housing providers to provide one-year “IPM interventions” at two MUH sites in the San Francisco Bay Area: a 75-unit SRO building in Contra Costa County and a 59-unit low-income apartment complex in Santa Clara County. This work was led by Regional Asthma Management and Prevention, a program of the Public Health Institute, and sponsored by the California Department of Pesticide Regulation.
IPM Intervention Methodology
We worked with the pest control operators already in contract with the housing providers at the two sites and revised existing contracts to include unit-by-unit monitoring. The project included funds used to offset the increased costs associated with these revisions. Operators were asked to design programs that included monitoring for cockroaches and bed bugs in every unit at least once annually. When pests were detected, management tactics would be selected according to the pest densities observed, with the overall goals of eliminating pest populations and reducing pesticide exposure. Typically, baits were used against cockroaches and desiccants, spot treatments, vacuums, and whole-room heat treatments were used against bed bugs.
Independently, our team of researchers assessed pest incidence and density at three points during the one-year interventions: before IPM protocols were in place (baseline), roughly six months afterward (midpoint), and about one year afterward (final). At each monitoring period, we placed one glue trap behind the refrigerator and one pitfall trap in contact with the bed or sleeping surface for periods of one to two weeks. We also trained management, staff, and tenants on pest awareness, prevention, and reporting. Monthly costs associated with the pest control programs were calculated, including contract values, supplemental or add-on service values, and on-site staff effort hours. These costs were compared to monthly costs before the proactive IPM interventions began. Finally, surveys and interviews were conducted with residents and staff at the study sites to measure their relative satisfaction with the proactive IPM programs. Access to residential units required written notices delivered 24 hours before intended entry and accompaniment by on-site staff.
Study Results
Bed bugs (Figure 1) were the primary pests at the Contra Costa County site while German cockroaches (Figure 2) were the primary pests at the Santa Clara County site. Other pests present at these sites included small flies (of the families Psychodidae, Phoridae, and Drosophilidae), rodents, and stored-product pests like meal moths and grain beetles. Baseline assessments revealed that more than 20% of the units inspected in Santa Clara County were infested with German cockroaches and that about 10% of the units in Contra Costa County were infested with bed bugs.
High-density infestations were addressed first, with heat treatments for bed bugs and high-volume gel bait applications for cockroaches. Several of these high-density infestations were only discovered due to the unit-by-unit proactive monitoring process.
Many residents refused our team's entry, especially during the baseline assessment in Contra Costa County. Participation and compliance improved markedly after an on-site education program for residents.
By the intervention's midpoint, pest density at both sites began to decrease (Figure 3), though pest incidence was largely unchanged. Incidence apparently increased since access to several infested units was only achieved several months after the intervention's onset. In these cases, distrusting residents gradually learned about the project's goals and about IPM through the resident education programs and eventually granted the team access to their units. The final pest assessment at the end of the one-year intervention showed continued decreases in pest density but relatively unchanged pest incidence at both sites (Figure 3). This means that the severe infestations (dozens to hundreds of cockroaches or bed bugs per unit) had been significantly decreased or eliminated but that a similar proportion of units were infested as had been at the beginning of the project. This may be very important for building-wide IPM since pests can disperse from high-density units to new units, usually those units next to or otherwise structurally continuous with the severe infestations. Overall, the pest control under the proactive IPM program was considered significantly more effective than the reactive programs previously in place.
Contract base values for the proactive IPM services increased significantly at both sites when compared to the reactive pest control services previously in place (Table 1). However, when considering the supplemental costs associated with add-on services, usually bed bug heat treatments not covered by the base contracts, monthly pest control costs decreased at both sites under the IPM programs (Table 1). In fact, monthly costs decreased by almost $1,000 at the Contra Costa County site, where a severe bed bug problem had been ongoing for many years prior to this project.
Site |
Santa Clara County (59 units) |
Contra Costa County (75 units) |
monthly service costs under reactive program |
$ 350 ($ 5.93 per unit) |
$ 240 ($ 3.20 per unit) |
annual supplementary costs under reactive program |
$ 18,565 ($ 315 per unit) |
$ 39,485 ($ 526 per unit) |
total annual costs under reactive program |
$ 22,765 ($ 385 per unit) |
$ 42,365 ($ 565 per unit) |
monthly service costs under IPM program |
$ 450 ($ 7.63 per unit) |
$ 360 ($ 4.80 per unit) |
annual supplementary costs under IPM program |
$ 16,044 ($ 272 per unit) |
$ 26,924 ($ 359 per unit) |
total annual costs under IPM program |
$ 21,444($ 363 per unit) |
$ 31,244 ($ 417 per unit) |
Annual Savings from IPM Program |
$ 1,321 |
$ 11,121 |
The majority of surveyed or interviewed residents (96% at the Contra Costa County site and 82% at the Santa Clara County site) reported being either “very satisfied” or “somewhat satisfied” with the pest management services being received, as compared with those in place before the intervention. About 87% of responding residents reported that they had received some educational materials about pests and IPM, and 93% of responding residents said that they would be likely to report pest sightings to management in the future. All staff interviewed reported that the IPM program was more effective, in their opinion, and that the unit-by-unit inspections allowed for more resident engagement surrounding pest control.
Overall, this project showed that proactive IPM programs that use regular unit-by-unit monitoring events can help detect unknown infestations, control severe infestations, reduce monthly costs, and satisfy on-site stakeholders. This result was somewhat unexpected, since IPM programs usually take more than one year to realize savings for MUH environments. In cases where expensive supplementary services, such as bed bug heat treatments, are common, however, savings under IPM programs may be realized very quickly.
[Originally featured in the Spring 2023 edition of the Green Bulletin Newsletter for structural and landscape pest professionals.]
/h2>/h2>Although all cockroaches in California are considered pests, the Turkestan cockroach is of particular concern. This cockroach has become increasingly common in California's residential outdoor areas because it has faster growth and higher reproduction rates compared to other cockroaches that live outdoors. Like other cockroaches, the Turkestan cockroach is considered both a nuisance and a public health issue.
What does the Turkestan cockroach look like?
Adult Turkestan cockroaches are about 1 inch in length. Females are slightly larger than males, dark-colored, flightless, and have distinct pale stripes right below their heads on their wing buds. Males are light brown with fully developed wings. Nymphs of the Turkestan cockroach have brown-reddish heads and dark brown bodies.
Where can you find Turkestan cockroaches?
Since these are outdoor cockroaches, they do not survive well indoors. Generally, they can be found in crevices in cement or rock walls, water meter boxes, outdoor drainage pipes, public drains, debris piles, and other dark, moist places.
What can you do about Turkestan cockroaches?
Use sticky traps or glue boards to detect and monitor cockroach populations. Securely store food and garbage, and limit excess moisture. Seal cracks and other openings to the outside and install door sweeps or weather stripping to prevent them from coming indoors. Pesticide baits can provide control, but pesticides alone will not solve a cockroach problem.
To learn more about Turkestan cockroaches, see the UC IPM Pest Notes: Cockroaches or visit this UC IPM page on Turkestan cockroaches.
- Author: Casey Hubble
[Originally published in the Summer 2022 issue of the UC IPM Green Bulletin]
The three-lined cockroach, Luridiblatta trivittata, (Figure 1) is the smallest cockroach species in California, with adults averaging only 5–7 mm in length. This newly introduced cockroach is native to North Africa and the Eastern Mediterranean. It was first detected in California around 2004 in Marin County, but it was not positively identified until 2009. Since then the three-lined cockroachhas slowly expanded its range to include the entire San Francisco Bay Area, south to San Luis Obispo, east to the foothills of El Dorado County, and north to Mendocino County.
Life cycle and biology
The three-lined cockroach lives in some of the most densely populated parts of northern California, but it's not a domestic pest species since it is rarely found indoors. Instead, these cockroaches prefer to live outdoors in natural or ornamental landscapes and can be found in matted thatch, compost bins, and leaf litter. Occasionally in late summer and early fall, adults will wander indoors through poorly sealed exterior doors and windows.
When inside, they are often misidentified as German cockroach nymphs (Blattella germanica), sometimes leading to unnecessary indoor insecticide applications. However, the number of stripes on the cockroach's body can help distinguish the species. The three-lined cockroach has three distinct stripes that run down the length of the adult's body, while German cockroach adults and nymphs have only two stripes (Figure 2).
It is unclear what the three-lined cockroach likes to eat in the landscape. Within the San Francisco Bay Area, this species has been observed feeding on the juices from overripe fruit in trees, and various food scraps from compost bins. Though these food items may be delicious treats for the cockroaches, they would appear to be atypical meals, since large populations of this insect have been found far from fruit or human food resources. Though scant, existing scientific literature classifies them as detritivores (organisms that feed on decaying organic material, especially plant matter), but it is unclear exactly what kinds of detritus might be preferred. Unfortunately, this question remains a mystery, since insect field diets can be notoriously difficult to determine.
Virtually no research has been conducted on this species, even in its native range. To better understand the biology and ecology of L. trivittata in California, the SF Bay Area Urban IPM Team launched a field study and several lab studies in 2021, revealing some interesting observations:
- Three-lined cockroaches have only one generation per year (Figure 3).
- Juveniles hatch in mid-April and develop through spring and early summer, eventually maturing into adults during July and August.
- Once mature, females lay egg cases (called oothecae) that will overwinter until next spring. Oothecae start out mint green in color, and as they develop, turn from olive green to dark brown before they are deposited into the landscape (Figure 4).
Mediterranean climates with long dry summers and short wet winters, found in California as well as their native habitat, seem to be ideal for this species. Juveniles do not seem able to hatch from their oothecae without some spring precipitation. On the other hand, too much water throughout the overwintering cycle may cause the eggs to mold, killing the nymphs before they can hatch. Females lay on average two or three oothecae per year. Each ootheca is very small (2 mm in length) and contains about 10 tiny cockroaches on average. This number is smaller than that observed for other outdoor cockroach species in California, where most average between 11-21 nymphs per ootheca.
The common name “three-lined cockroach” was suggested by the SF Bay Area Urban IPM team and officially adopted by the Entomological Society of America. This name is not only an accurate description of the insect's appearance but is also reflected in the scientific name Luridiblatta trivittata.
What can you do?
Proper identification is crucial to providing effective pest control services. While the three-lined cockroach prefers to live outside (only occasionally wandering indoors), the German cockroach lives exclusively indoors and is considered a major public health pest. Signs of the three-lined cockroach indoors may signal the need for better structural exclusion while German cockroach infestations will need immediate remediation. If you are unsure of the pest species, contact your county's UC Cooperative Extension office, Department of Agriculture, or Vector Control District for confirmation.
Though the three-lined cockroach may be considered a nuisance pest when found in large numbers, it may not ever call for control measures. There are many unknowns remaining about this species, such as how far it may expand throughout California and neighboring states. To help us track the spread of the three-lined cockroach, you can submit photos and report sightings to iNaturalist (https://www.inaturalist.org/) or BugGuide (https://bugguide.net/node/view/15740); these civic science data can be pooled to create distribution maps (Figure 5).
This research was funded by the California Department of Pesticide Regulation.
References:
California Plant Pest & Disease Report Vol. 25. 2009. CDFA
Sutherland AM, Choe D-H, Rust MK. 2019. UC IPM Pest Notes: Cockroaches. UC ANR Publication 7467. Oakland, CA.
Djernæs, Marie, et al. "Phylogeny and life history evolution of Blaberoidea (Blattodea)." Arthropod Systematics & Phylogeny 78.1 (2020): 29-67.
/h2>/h2>/h2>/span>Advice for Home Gardeners from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Home Gardener's Request: I found 2 of these little beetle like bugs about 1/4-inch long in our home. Are they cockroaches? I've seen them outside as well.
Following is a link to a UC Master Gardener Program Blog from Solano County and below that is an excerpt from the blog that explains the biology and how to manage this new pest. The comments/responses included with the original blog are of interest to as they provide comments from gardeners with this cockroach in their home and garden as well as further comments from a UC entomologist: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=14445
This cockroach is an outdoor species with a penchant for coming inside during drought, flooding, or to overwinter. It should be treated as a nuisance 'invader from outdoors' species, similar to Oriental cockroaches. General guidance to prevent this nuisance cockroach include:
- prevent household invasions by properly sealing cracks and crevices, providing fine mesh screens for open windows, and installing door sweeps (this exclusion process is a bit difficult to accomplish due to the tiny size of this roach, but it should be the goal)
- eliminate suitable habitat near structures by reducing moisture, maintaining structural perimeters (one meter from foundation) free of dense plantings and mulches, and by reducing sources of decomposing organic matter such as woodpiles and compost heaps (especially in close proximity to doors and windows)
- this species serves as a decomposer in the garden and landscape (meaning it feeds on decaying material and typically occurs in leaf litter, plant debris, mulch, and compost piles) and is unlikely to become established within structures. At most, it might be considered a nuisance, as stated above. In many cases, no management actions whatsoever will be necessary against this insect provided you follow the general guidance above.
We hope you find this information helpful for dealing with your new neighbor. Please contact us again if you have more questions.
Help Desk of the UC Master Program of Contra Costa County
Notes: Contra Costa MG's Help Desk is available almost year-round to answer your gardening questions. Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone: (925) 608-6683, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.edu/HortCoCo/ You can also subscribe to the Biog.