Online resources & key organizations
START HERE
University of California, Statewide Integrated Pest Management Program (UC IPM). www.ipm.ucanr.edu Search: Mosquitoes.
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NOTE: FEDERAL WEBSITES
U.S. Government websites are not included here because, under the current Administration, some websites have been altered to conform with White House policies that differ from enacted laws, others are no longer updated, and some have been taken down entirely. See the EDGI report, August 2025. The George Wright Society, of which I'm a member, is working to preserve deleted information. -TT
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California Department of Public Health (CDPH). www.cdph.ca.gov Search: Mosquitoes. Key document: “Best Management Practices for Mosquito Control.”
California Department of Pesticide Regulation. www.cdpr.ca.gov Promotes “sustainable pest management,” which aims to accelerate adoption of IPM.
San Gabriel Valley Mosquito and Vector Control District (SGVMVCD). www.sgvmosquito.org
The local authority directly responsible.
American Mosquito Control Association (AMCA). www.mosquitoes.org
Mosquito and Vector Control Association of California (MVCAC). www.mvcac.org
Xerces Society for Invertebrate Conservation
Invertebrates are animals without a backbone; they include insects and spiders as well as many other forms of life. The website includes guidance on reducing use of pesticides.
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OTHER PESTS
The UC IPM website -- www.ipm.ucanr.edu -- has detailed advice on controlling many kinds of pests found locally, including ants, fleas, and venomous spiders (as well as mammals such as mice, rats, opossums, raccoons, gophers, coyotes -- and others).
BITING MIDGES (no-see-ums)
These tiny flies found in MSAG cause painful bites that can itch for days. Methods for abatement are generally the same as for mosquitoes. Small-mesh window screens offer better protection than standard screens, but can reduce air flow.
WHAT ABOUT OUR NEIGHBORS?
Mosquitoes don't respect property lines. As we in the Gardens work to control them in our 31 acres, we plan to meet with those responsible for neighboring properties, which include two schools.
What's the threat?
>> Top of page: The invasive Asian tiger mosquito (Aedes albopictus)
>> Above: The native southern house mosquito, Culex quinquefasciatus, "Quinx" (male/female)
The kinds of mosquitoes that live in MSAG can carry viruses and bacteria that cause serious illness. In a warming climate, insect-borne diseases once found only in the tropics are expanding northward. One informed estimate is that this is happening at a rate of 30 miles a decade.
WEST NILE VIRUS
This is the most common and most serious vector-borne disease in California and locally. More than 8,000 human cases and nearly 400 deaths have been reported in California since 2003. West Nile is spread by medium-sized, brown Culex mosquitoes (illustrations above).
West Nile virus infections can range in severity from no detectable symptoms to West Nile fever to severe neuroinvasive diseases such as West Nile encephalitis, West Nile meningitis, or West Nile meningo-encephalitis.
AEDES VIRUSES
Two species of invasive Aedes mosquitoes arrived in Claremont and Pomona in 2016-2017: Aedes aegypti, the yellow fever mosquito, and Aedes albopictus, the Asian tiger mosquito. Both are small, black mosquitoes with white stripes on their back and legs. The large image at the top of the page is of the tiger mosquito; the yellow fever mosquito is very similar. These insects bite during the day and can transmit some of the most debilitating and deadly mosquito-borne viral pathogens known to humans, such as Zika, dengue, chikungunya, and yellow fever. In California, only dengue fever has been found so far.
A third Aedes species, Aedes notoscriptus, the Australian backyard mosquito, was found in Monterey Park in 2014 and has since been detected in other locations in Los Angeles and San Diego counties. More information.
PROTECTING PETS, NON-TARGET WILDLIFE, AND NATURAL ENEMIES
Insecticides must be applied in ways that minimize harm to our pets as well as vulnerable and beneficial wildlife such as hummingbirds, butterflies, ladybugs, honey bees, and dragonflies. According to UC IPM,
"Most gardens contain far more beneficial insects, than pest insects. . . It is important to encourage these natural enemies by avoiding pesticides that kill them."
RISK OF MOSQUITO BITES BY MONTH IN CALIFORNIA
Page from the California Department of Public Health . The risk is highest when the weather is hot and mosquitoes are most active. Locally, mosquitoes can still be laying eggs into mid-November and even later.
WHAT IF YOU'RE RARELY BITTEN?
Mosquitoes bite some people and not others. This is mainly because different people have different blood types or body scents. Even though some of us are rarely bitten, please keep in mind that everyone benefits from mosquito abatement.
Moving toward Integrated Pest Management
Moving toward Integrated Pest Management
We don’t need to stop using pesticides suddenly or entirely, but the Gardens should move toward “integrated pest management” (IPM), the method promoted by California state and local authorities for almost 50 years.
The California Department of Pesticide Regulation has a simple definition of IPM: "Any approach that uses the least toxic, effective method to solve pest problems."
Here's a more detailed definition by the University of California’s Statewide IPM program -- www.ipm.ucanr.edu -- which has been a leader globally in developing this method. It defines Integrated Pest Management as “an ecosystem-based strategy that focuses on long-term prevention of pests or their damage .. . Pesticides are used only after monitoring shows they are needed . . . and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment.”
USING INSECTICIDES WHEN NEEDED
The state health department cautions that insecticides “must be used by trained personnel and after careful planning.” It calls for applying insecticides selectively to the proper life stage of the mosquito, and in a manner that will “minimize personal hazard to the applicator and other people in the vicinity.”
WHERE MOSQUITOES BREED AND HANG OUT
Mosquitoes go through four life stages: egg, larva, pupa, and adult. Some species lay eggs in stagnant water; they can hatch within a day or two. Our koi ponds are monitored for eggs and larvae (see illustrated item below), but stagnant water can be found elsewhere in the Gardens.
Other species lay eggs on moist soil and don’t hatch until the surfaces are flooded, which may occur months later.
Adult mosquitoes often rest on the back of large leaves of trees and shrubs.
WORKING WITH MSAG’s LANDSCAPE AND INFRASTRUCTURE PROJECTS
Pest control will be taken into account in choosing new plantings and updating irrigation, drainage, wiring, and outdoor lighting systems.
A LITTLE HISTORY
J. Wakeli Wekesa, "A Century of Mosquito Control in California, 1915-2015."
MALARIA: IT'S GONE, BUT IT CAN RETURN
Malaria was eradicated in California in the 1940s. Although the Anopheles mosquitoes that can spread malaria are still around, they are carefully monitored. Currently, the Plasmodium parasite that causes malaria is absent, but there can be outbreaks.
MORE FACTS & TIPS
WHAT'S THE LIZARD DOING HERE?
To teach us a lesson.
Mt. San Antonio Gardens is home to a lot of western fence lizards. These little reptiles, harmless to us, are the reason Lyme disease is rare in our region. They are the main hosts for the ticks that carry Lyme disease bacteria, and have a protein in their blood that kills the bacteria in ticks that feed on them.
The lesson is that natural predators like these lizards -- and our owls, hawks, seldom-seen bats, and dragonflies (see below) -- need our understanding and protection.
HERE'S A SCIENTIFIC PAPER BASED ON RESEARCH IN NEARBY TOWNS
The researchers looked at what goes on in underground stormwater treatment plants in Ontario and Rancho Cucamonga. They focused on Culex quinquefasciatus ("Quinx"), a primary vector of West Nile virus in Southern California. Although egg-laying was greatest from mid-July to mid-November, it continued through the winter, pointing to a need to monitor activity all year long.
THE NEXT STEP: SUSTAINABLE PEST MANAGEMENT
Sustainable Pest Management (SPM) was written into California law in 2024. It is defined as a "holistic, whole-system approach ... that builds on the existing practice of Integrated Pest Management (IPM) to include the wider context of three sustainability pillars:" human health and social equity; environmental protection; and economic vitality
[Food and Agriculture Code Section 11412] .
Does this matter to Mt. San Antonio Gardens? Yes, if we are serious about promoting sustainability, including human health. We need to keep in touch with new developments for our own sake in the Gardens and because our residents are able to spread the word through their own networks.
Inserting these few phrases into state law represents a major shift in policy. For more information, visit the website of the Department of Pesticide Regulation: https://www.cdpr.ca.gov/spm-ipm-overview
HOW TO KEEP FROM BEING BITTEN BY MOSQUITOES
The University of California Integrated Pest Control program has detailed, reliable information on its website, www.ipm.ucanr.edu.
Consumer Reports reviews and ranks brands and products, www.consumerreports.org.
The most effective repellents to apply to your skin include a chemical called DEET (diethyltoluamide). For those who want to avoid DEET, these websites list alternatives with notes on their effectiveness and safety.
Different repellents are used on clothing; these include permethrin.
A compound called piaridin, also known as icaridin, may be used on both skin and clothing.
Although state and federal agencies have guidance on their websites, their advice is based on recommendations of the U.S. Environmental Protection Agency and may be outdated (see Note on Federal Websites, above).
WEAR THE RIGHT CLOTHING
Consider wearing long sleeves and long trousers that cover your ankles. Avoid wearing dark or bright colors like black, red, and orange. Mosquitoes stay away from white and pale shades of colors.
DUMP STANDING WATER
Mosquitoes breed in stagnant water in such places as birdbaths and outdoor plant saucers and pet bowls. Do this every day or two (not weekly, as we were recommending previously).
FIX SCREENS
Make sure screens on windows and doors fit tightly.
USE MOSQUITO TRAPS INDOORS (BUT NOT ZAPPERS AND NOT OUTDOORS)
Many kinds of indoor traps are available. A local expert suggested the kind that plug in to an electrical outlet, use ultraviolet light, and have sticky boards to catch the flying mosquitoes attracted to the light. I'm trying them out. Let me know if you have other suggestions, tedtrzyna@gmail.com.
USE ELECTRIC FANS ON PATIOS In small areas such as patios, Consumer Reports found that an oscillating pedestal fan was very effective in controlling mosquitoes because "it makes it more difficult for them to fly against the steady breeze, and also helps disperse the carbon dioxide we emit when we breathe -- a good thing because mosquitoes use carbon dioxide as a guide to finding humans when they’re looking to feed."
METHODS THAT DON'T WORK OR CAN CAUSE HARM
METHODS THAT DON'T WORK OR CAN CAUSE HARM
DON'T USE METHODS THAT CAN GIVE YOU A FALSE SENSE OF SECURITY
Some things, including those listed below, may seem to work but don't, or actually do work but in a limited way. They can give us a false sense of security, so beware.
VITAMINS DON'T WORK
Some Gardens residents swear by taking vitamin B to keep mosquitoes from biting them. However, a recent survey of the scientific literature states, "The scientific consensus is, unequivocally, that oral repellents don’t exist. Despite extensive searches, no food, supplement, medication, or condition has ever been proven to make people repellent."
DON'T USE "BUG ZAPPERS" OUTDOORS
These electric insect traps may seem to be effective, but mosquitoes aren't attracted to light, and the zaps we hear are when other kinds of insects hit the screen, including beneficial ones. Mosquito traps designed for indoor use are a different matter; see the column at left.
PLANTS DON'T REPEL MOSQUITOES
Some plants like marigolds and mints have compounds that keep insects from feeding on them. However, they don't release these compounds into the air, so it's not worth planting them to repel mosquitoes. See https://www.thespruce.com/do-marigolds-keep-mosquitoes-away-11754142
THE KOI PONDS
THE KOI PONDS
THE KOI PONDS
Most kinds of mosquitoes need stagnant water to breed. Our koi ponds have moving water and were free of mosquito eggs and larvae when tested in 2024. This testing will continue on a regular basis.
Koi, which are ornamen- tal carp, don't eat a lot of eggs or larvae. However, they stir up the water, making it less hospitable for femal
Most kinds of mosquitoes need stagnant water to breed. Our koi ponds have moving water and were free of mosquito eggs and larvae when tested in 2024. This testing will continue on a regular basis.
Koi, which are ornamen- tal carp, don't eat a lot of eggs or larvae. However, they stir up the water, making it less hospitable for female adult mosquitoes to lay eggs.
If the the San Gabriel Valley Mosquito and Vector Control District finds mosquito eggs or larvae in a pond, it will usually introduce mosquito fish (Gambusia), a small species (up to 2.8 inches long) not native to California that consumes large quantities of mosquito eggs, larvae, and adults.
The Xerces Society, a leading authority on invertebrate conservation, does not recommend introduction of mosquito fish to control mosquitoes because it is "a voracious generalist predator that eats a wide array of aquatic invertebrates . . . and can actually worsen a mosquito problem, as they eliminate the predatory bugs, beetles, and crustaceans that would otherwise prey on mosquito larvae."
DRAGONFLIES
THE KOI PONDS
THE KOI PONDS
Spraying pesticide can harm dragonflies, which are a good example of natural pest control. One dragonfly can eat hundreds of mosquito larvae and adult insects in a day. In the Gardens, they hang out around the koi ponds and fountains.
In Southern California, we have 77 species of dragonflies. This one, the flame skimmer (Libellula sa
Spraying pesticide can harm dragonflies, which are a good example of natural pest control. One dragonfly can eat hundreds of mosquito larvae and adult insects in a day. In the Gardens, they hang out around the koi ponds and fountains.
In Southern California, we have 77 species of dragonflies. This one, the flame skimmer (Libellula saturata) is one of the most common.
Learn more: https://xerces.org/publications/guidelines/backyard-ponds.
MONARCHS
THE KOI PONDS
MONARCHS
Spraying pesticide can harm monarch butterflies.
Adult monarchs lay their eggs only on milkweed plants, and monarch caterpillars feed only on milkweed. However, monarchs need milkweed species native to where they live, rather than the tropical species sold in some commercial nurseries. In the Gardens, residents have planted native sp
Spraying pesticide can harm monarch butterflies.
Adult monarchs lay their eggs only on milkweed plants, and monarch caterpillars feed only on milkweed. However, monarchs need milkweed species native to where they live, rather than the tropical species sold in some commercial nurseries. In the Gardens, residents have planted native species and worked with the Administration to remove any tropical milkweed remaining on the grounds. Probably for these reasons, monarchs are frequently seen in the Gardens.
More: The Xerces Society has issued a report on the extent of this problem in California and what to do about it to protect these fascinating migratory insects.