Controlling MOSQUITOES in Mt. SAN ANTONIO GARDENS

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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 in pest management 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. According to the state Department of Pesticide Regulation, "As climate change and severe weather introduce new and increasing  pest pressures, current tools become less effective at managing pests,  and scientific studies identify significant impacts of high-risk  pesticides that require increased restrictions on their use, California  is focused on bringing safe, effective pest management tools to market  faster."     The goal of the Sustainable Pest Management Roadmap, produced through a two-year collaborative process, is for California, by the year 2050, "to replace priority high-risk pesticide use with sustainable pest management and for sustainable pest management to become the state’s de facto pest  management system." For more information, visit the website of the Department of Pesticide Regulation:https://www.cdpr.ca.gov/spm-ipm-overview
 

 has detailed, reliable information on its website, 

www.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.

ompound called piaridin, also known as icaridin, may be used on both skin and clothing.  P

     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 outdoor 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." 

USE BIOLOGICAL CONTROL AGENTS IN THE KOI PONDS

See the

If mosquitoes become an issue,

the pond can be treated with “dunks”

or briquettes of a biological control

agent called Bacillus thuringiensis is-

raelensis, or Bti. This bacterium pro-

duces a crystalline protein toxin that

disrupts the guts of mosquito larvae

that eat it, killing them before they can

develop into adults. Bti is only toxic to

members of the order Diptera (true

flies), so be aware that other groups such as beneficial non-biting midges and crane flies can

also be affected. Mosquito and midge larvae are an important food source for many pond-

dwelling animals, so consider very carefully whether, when, and how frequently treatment

is needed.

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.

Insecticides Used in Water. Bacillus thuringiensis subspecies israelensis (Bti) is a bacterium that forms spores which produce proteins toxic to  mosquito larvae. To be effective, mosquito larvae must eat the  compounds, which act as a stomach poison that damages mosquito midgut  cells. Like the closely related forms of Bt used by gardeners to control  specific insect pests, Bti is highly selective, killing only mosquitoes  and the larvae of a few other related flies. This biopesticide is not  effective against pupae, since they don’t feed. Bti is marketed in a  variety of formulations for the homeowner, the most common being  Mosquito Dunks which last for about 30 days in water.

Methoprene is an insect growth regulator (IGR), a mosquito hormone  mimic that is applied to standing water and inhibits the emergence of  adult mosquitoes. Examples of commercially available formulations  include Altosid Pro-G and Pre-Strike Mosquito Torpedo. Spinosad is a neurotoxin produced naturally by some bacteria and is used as an  insecticide against many types of insects. For mosquito control, it is  sold as Natular DT and appled to standing water. 

Outdoor Sprays. Using insecticide sprays or outdoor  foggers for controlling adult mosquitoes has limitations. While they can  provide a temporary reduction of the adult population—which can be  useful if you make the application shortly before a backyard picnic or  family gathering—alternative, more long-term approaches for controlling  mosquitoes are preferable. Equipment for applying outdoor sprays is  expensive and complex. The use of systems that continuously release  small amounts of insecticides is not recommended.

   Regardless of the product that you choose to use against mosquitoes,  always follow the instructions for the amount and appropriate habitats  for use found on the product’s label. It is a violation of federal law  not to follow the instructions on the label!

   Probably the best way to protect yourself from mosquito bites is to  avoid places where their densities are high and avoid being outside when  mosquito activity is at its highest. In mountainous areas, most  mosquito species bite during morning and afternoon hours and often not  at all when it is dark. In some low-elevation areas, such as the Central  Valley, some mosquitoes tend to bite at night, while others bite during  the day. 

   Here are some ways to protect yourself from mosquito bites:

• Maintain conditions around the home to reduce contact with mosquitoes. 
• Repair broken window and door screens.
• Eliminate small pools of standing water.
• Reduce time outdoors, particularly in early morning and evening hours when host-seeking Culex mosquitoes are most active.
• Wear long pants and long-sleeved shirts.
• Apply mosquito repellent to exposed skin and to clothing.

Repellents. If you find yourself in a situation  where you can’t avoid mosquitoes, first minimize the amount of exposed  skin surface by wearing a hat or head net, long trousers, and a  long-sleeved shirt. Some mosquitoes will bite through lightweight  clothing, but the number of bites you receive will decrease if you cover  most areas of your body.

   When mosquito densities become very high, it is best to apply a  mosquito repellent. The Centers for Disease Control and Prevention (CDC)  recommends using products containing active ingredients registered by  the U.S. Environmental Protection Agency (EPA) for use as repellents  applied to skin and clothing. An EPA registration indicates the active  ingredients of repellents have been tested for human safety when applied  according to the instructions on the label.

   The CDC currently recommends two general types of repellents for use  on skin: conventional and biopesticide repellents. Conventional  repellents include compounds such as DEET (N,N-diethyl-m-toluamide or  N,N-diethyl-3-methyl-benzamide) and Picaridin (KBR 3023:  2-[2-hydroxyethyl]-1-piperidinecarboxylic acid 1-methylpropyl ester).  DEET and Picaridin are used most commonly to repel mosquitoes.

   Biopesticide repellents are derived from natural materials or are  synthetic versions of the natural product. The synthetic form of oil of  lemon eucalyptus (OLE: use only when formulated as a repellent. The pure  form of OLE is not currently registered by the EPA.) and IR3535  (3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester) are two  recommended biopesticide repellents. A synthetic alternative to natural  OLE is PMD (para-menthane-3,8-diol) and is recommended by the CDC. PMD  isn’t recommended for use on children younger than 3 years old. These  repellents are available at retail outlets under different product  names: the active ingredient and its percentage in the formulation are  listed on the label of each product.

   New repellents are continually being developed and tested. The  federal government’s latest recommendations for mosquito repellents can  be found on the CDC’s website: wwwnc.cdc.gov/travel/yellowbook/2020/noninfectious-health-risks/mosquitoes-ticks-and-other-arthropods and EPA’s website: www.epa.gov/insect-repellents.

   A repellent’s effectiveness and duration of protection vary  considerably among products and mosquito species. Effectiveness  typically lasts 4 or fewer hours depending on wind, high temperatures,  high humidity, and perspiration amounts.

   In general, higher concentrations of active ingredient provide a  longer protection time, regardless of the active ingredient, although  concentrations greater than 50% don’t offer a marked increase in  protection time. Products with less than 10% active ingredient might  offer only limited protection, often only 1 to 2 hours.

   Products that offer sustained release or controlled release  (micro-encapsulated) formulations, even with lower active ingredient  concentrations, might provide longer protection times. Regardless of  which product you use, if you start to get mosquito bites, reapply the  repellent according to the label instructions or remove yourself from  the area if possible. 

   DEET is the most effective mosquito repellent if you will be out for  long periods where mosquitoes are abundant. However, DEET is an  irritant to some people, and repellents containing high DEET  concentrations can damage synthetic materials such as clothing or  plastics. Apply sparingly to all exposed skin. Special formulations for  children contain low concentrations of the chemical in an oil-based  medium that slowly releases the compound and limits its absorption  through the skin; these formulations also work well for adults.

   If you wish to avoid DEET, many of the EPA-approved alternative  repellents are as effective or are more effective for some people than  are low concentrations of DEET, especially when only short-term  repellency (fewer than 2 hours) is desired and mosquitoes aren’t very  abundant.

   In addition to the previously mentioned repellents, plant oils such  as those from birch, bluestem grass, geranium, pine, rosemary,  spearmint, yarrow, lantana, and neem somewhat repel mosquitoes; but most  aren’t available in commercial mosquito repellents. The insecticide permethrin functions as a repellent when applied to clothing, but it should never be applied directly to skin.

   The EPA recommends several precautions when using insect repellents.

• Apply repellents only to exposed skin and clothing; never use repellents underneath clothing. 
• Don’t apply repellents over cuts or irritated skin.
• Never spray repellents directly onto your face; apply the  repellent onto your hands first, then use your hands to apply the  product sparingly onto your face and head. 
• Never let children handle repellents.
• A small amount of repellent is sufficient to effectively deter mosquitoes. 
• After returning indoors, wash treated areas with soap and water. 
• If you develop a rash after using a repellent, wash the affected  area with mild soap and water and seek guidance from a physician or  poison control center. 
• Always read and follow the directions on the product’s label.

Other Repellent Products. Research has shown that  the effectiveness of most other products marketed to repel mosquitoes  differs appreciably. Some products such as clip-on dispensers emitting  metofluthrin which kills and repels mosquitoes have shown some promise  in limited studies. Manufacturers claim that clip-on, battery-operated  dispensers for the pyrethroid pesticide metofluthrin repel mosquitoes  for up to 12 hours per refill; but like most repellents, effectiveness  varies among users. Wristbands that contain an aromatic repellent,  ultrasonic emitters, electric grids, electronic repellers, aromatic  plants (the most common one is the so-called mosquito plant, Pelargonium x citrosum), incense coils, vitamin B1, and mixtures of brewer’s yeast and garlic are ineffective.

   Oil of citronella, which is extracted from Andropogon nardus, has a reputation for repelling mosquitoes. Burning citronella candles or mosquito coils containing allethrin works best if there is relatively little air movement, but these products are only for use outdoors.

Mosquito and Vector Control Agencies

   The goal of mosquito management is to keep populations below levels  where they become a nuisance or a public health problem that leads to an  outbreak of disease. Mosquito manageCANDLES, COILS, AND BATTERY-POWERED DIFFUSERS

PATCHES, STICKERS, WRIST AND ANKLE BANDS, ETC.

Consumer Reports tested three methods for controlling mosquito activity in a large outdoor area: citronella candles, an oscillating pedestal  fan, and a battery-powered area diffuser that emitted geraniol, a  natural repellent derived from plants.
    CR  found that "the fan is far more  effective than citronella candles or the geraniol diffuser. . . .  While a fan makes it more difficult for mosquitoes to  fly against the steady breeze, it 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." www.consumerreports.org
    Mosquito repellent coils, which burn over many hours, were not included in this CR project, but are given mixed reviews elsewhere.
    Patches, stickers, and wristbands containing mosquito repellents are effective only where they meet the skin.