Q. What’s the life cycle of a mosquito and why should I care?

A. Mosquitoes have four stages in their life cycle: egg, larva, pupa, and adult. The first three stages are aquatic. The female mosquito lays eggs on or near a water surface; the eggs hatch a few hours or days later and the larvae emerge. The larvae feed on aquatic algae and bacteria. As they mature, they outgrow their skin, grow a new skin layer, and shed the old one, a process called molting. After the fourth growth-molt cycle, the mosquito enters the pupal stage. A few days later, the adult mosquito emerges from the pupal case and flies away.

Because three (3) of the four (4) life stages of a mosquito are aquatic, the best way to control them is to target their aquatic stages.  By denying them the water they need to develop, mosquitoes cannot complete their life cycle and they die. For this reason, the Orange County Mosquito and Vector Control District asks the public to eliminate any standing water around the home or workplace and to report standing water that cannot be eliminated. 

Q. What are larvicides and adulticides?

A. Control of mosquitoes while in the larval stage is the backbone of NFMADs abatement program.  Larvicides are products used to reduce immature mosquito populations when they are still in the water.  Larvicides, which can be biological or chemical-based, are applied directly to water sources that hold immature mosquitoes, including eggs, larvae, and pupae.  Larvicides reduce the overall mosquito population by limiting the number of biting adult mosquitoes produced from a water source.

Adulticides are products that rapidly reduce adult mosquito populations. This can become necessary when larval control measures no longer reduce the presence of biting-adult mosquitoes, or there is significant threat of disease transmission in an area. The most common method of adulticiding is ultra-low volume (ULV) spraying. ULV spraying is the process of putting very small amounts of liquid into the air as a fine mist of droplets. These droplets float on the air currents and quickly eliminate mosquitoes that come into contact with the droplets. Sprays can be applied from backpacks, trucks, helicopters, or airplanes. Adulticides immediately reduce the number of adult mosquitoes in an area, with the goal of reducing the number of mosquitoes that can bite people and possibly transmit disease.

Q. What type of insecticides are being used by the North Fork Mosquito Abatement District?

 A. For larval mosquito control, NFMAD typically utilizes Bacillus thuringiensis israelensis (Bti), Bacillus sphaericus and Saccharopolyspora bacterial products), or insect growth regulators, (IGRs) which prevent the immature mosquito from becoming a biting adult mosquito.

Adult mosquito control products used by NFMAD can be placed into two groups (Pyrethrins and Pyrethroids), both of which can be formulated with a synergist chemical to increase their efficacy:

• Pyrethrins are the active ingredients in pyrethrum, an extract of the flower Chrysanthemum cinerariifolium. Pyrethrins are natural insecticides that act by blocking chemical signals at nerve junctions.
• Pyrethroids are the synthetic version of pyrethrins that also act by blocking chemical signals at nerve junctions.
• Piperonyl butoxide (PBO) is a synergist that is usually incorporated with pyrethrins and pyrethroids. PBO enhances the effect of these insecticides by inhibiting cytochrome P450, a class of enzymes that break down the insecticides. This allows the insecticides to be effective with less active ingredient than would otherwise be required.

The U.S. Environmental Protection Agency (US EPA) approves the use of insecticides nationally and  Colorado Dept of Public Health & Envirnoment (CDPHE) & Water Quality Control Division (WQCD)  approves their use in Colorado.  Before pesticides are registered by the US EPA or CDPHE & WQCD, they must undergo extensive and time-consuming laboratory testing for environmental impacts as well as test for acute and chronic health effects.

Q. When does the District use chemical mosquito control (pesticide)?

A.  Chemical control is used for immature mosquitoes in water when biological control and source reduction is not plausible or effective.

Chemical control for adult mosquitoes is necessary when biological and physical control methods are unable to maintain mosquito numbers below a level that is considered tolerable, or when emergency control measures are needed to rapidly disrupt and reduce the transmission of disease to humans.

All products are registered with the Colorado Dept of Agriculture (CDA) and are applied by trained North Fork Mosquito Abatement District technicians.

More information on other chemicals used in mosquito control  (larvicide and adulticide) can be found in the HERE.

Q. What is the Centers for Disease Control’s (CDC) position regarding the use of chemical mosquito control?

A. The CDC has guidance for all aspects of larval and adult mosquito control. For their updated guidelines and planning resources that provides detailed guidance about the use of mosquito control measures, including suggestions for an elevated response and the actions that are possible at different levels of virus activity.

Q. How will these pesticides affect me and my family?

A. At the rates these products are applied (2 tablespoons or less per acre), they do not pose a risk to you or your family. In fact, some lice control products that are applied directly to a person’s head, contain an active ingredient that is often used in adult mosquito control products but the lice products are applied at a much higher rate. For more information on insecticides and public health, consult the U.S. Environmental Protection Agency, which oversees the registration of these chemicals. The National Pesticide Information Center (NPIC) and the Centers for Disease Control and Prevention also post their mosquito control resources online.

Q. What should I do if I think that I am having health problems because of pesticides used in my area?

A. If you are experiencing health problems for any reason, it is important to see your health care provider promptly.

Q. Do I have to go indoors during spraying?

A. The District sprays public health pesticides approved by the US EPA for use on and over outdoor residential and recreational areas. It is not necessary to close doors or windows. The spray will dissipate from the treated area and degrade quickly in sunlight. In some instances, mosquito control backpack sprays may leave wet surfaces and should not be contacted until dry.

Q. Can pets go outside during spraying?

A. The materials used for controlling mosquitoes, when used in accordance to the label, are not harmful to pets. Many times, it is the same materials used to treat cats and dogs for fleas and ticks. However, if you choose to reduce your pet’s exposure, keep them inside during spray applications.

Q. Should I close my windows when a spraying is scheduled in my area?

A. It is not necessary to close doors or windows. The spray will dissipate from the treated area and degrade quickly in sunlight. However, residents may take additional measures to achieve personal comfort during the application.

Q. Why are you treating my neighbor’s yard?

A. When the presence of a mosquito-borne virus is identified in a neighborhood, the District deploys personnel to investigate the residential and commercial properties in the area. Products to control mosquitoes are applied on residential properties with homeowner/property owner consent.

Q. Will the adult mosquito spraying affect my swimming pool water, lawn furniture, play equipment, toys, etc.?

A. Your swimming pool water and items found in your yard will not be affected.

Q. What if I have a vegetable or fruit garden?

A. Just as you normally would, wash your vegetables and fruit before you eat them.

Q. Will the adult mosquito spraying affect bees?

A. When adult mosquito control spraying is conducted using ULV applications at the label rates at night, there should be no impacts to bees. In some instances, the NFMAD may apply adult mosquito control products during the day to either control resting mosquitoes infected with West Nile virus; or to control invasive Aedes mosquitoes.  If a daytime application is necessary, applicators are trained to avoid blooming plants, bee hives, or other areas where bees may congregate.

Q. How do I protect the bees in hives?

A. If residents are still concerned about their hives, and bees are currently bearding on the side of the hive, the hive can be draped in wet burlap.  The burlap is wet with water and then draped like a curtain over the hive with an opening in the front for bees to enter and exit.

Q. Are there special notices for bee keepers?

A. Beekeepers can register hive locations with the NFMAD.  

Q. I have an air conditioner. Should I turn it off if spraying is scheduled in my area?

A. It is not required to turn off air conditioning units during or after mosquito control spray events. However, if you have a window or wall air-conditioning unit that is running on the fan setting, you may turn it off so that air is not brought in from the outside. Window and wall units running on cooling settings do not draw air from outside of the home, so there is no need to turn your air conditioning unit off. Central air-conditioning units cool recirculated air in your house. Since a central air-conditioning unit does not pull in outside air, there is no need to turn it off.

Q. Where can I get additional information regarding specific insecticides?

A. Questions concerning specific insecticides can be directed to the U.S. Environmental Protection Agency, as this agency has responsibility for the registration of insecticides. Many issues are addressed on the EPA’s Mosquito Control Web site.

The National Pesticide Information Center (NPIC) provides insecticide information and questions about the impact of insecticide use on human health. NPIC is cooperatively sponsored by Oregon State University and the U.S. Environmental Protection Agency.

NPIC can be reached online or toll-free: 1-800-858-7378. The Center for Disease Control and Prevention have also posted guidance and planning resources online.

Q.  Do you charge for services? 

A.  No - we are a Special District funded by property tax assessments and our services are available to all our constituents within our covered area.

Q. What is "mosquito control"?  

A.  Mosquito control is the process of actively reducing the number of mosquitoes. Comprehensive mosquito control can use one or more approaches that target different environments and life stages of the mosquito.

Q.  Why should mosquitoes be controlled?  

A.  The most important reason to control mosquitoes is to reduce the likelihood of diseases such as West Nile virus being transmitted to people through mosquito bites. Throughout history, no insect has been a more significant contributor to human discomfort, disease, and death than the mosquito. Even mosquitoes that do not transmit disease can be bothersome in their biting behavior. In severe instances nuisance mosquitoes can be economically detrimental to businesses, and reduce the quality of life for residents.

Q.  How is mosquito control accomplished? 

A.  Most mosquito control programs reduce mosquito populations through a multi-faceted approach known as Integrated Pest Management (IPM). A mosquito has four life stages: egg, larva, pupa, and adult. In the life cycle of the mosquito, only the adult stage does not require standing water. An IPM program targets each life stage of the mosquito, but is intended to eliminate as many mosquitoes as possible before they emerge as biting adults. We engage in larval and adult mosquito population monitoring and control, monitor activity of mosquitoes and disease agents, and provide information to the community. The scope and range of activities within each program vary according to their location, climate, and available resources. Many areas in the North Fork Valley are not within the jurisdiction of our established mosquito control program.

Q.  Can we eliminate mosquitoes?

A.  No, mosquitoes live in many different habitats, and it is impossible to find and treat all of the places that they breed. Furthermore, mosquito control is not intended to eliminate mosquitoes. The goal of a mosquito control program is to reduce adult mosquito populations to a level that minimizes the possibility of people and animals getting sick from diseases associated with mosquitoes, and reduces biting to a level that most people find tolerable. Limiting mosquito populations through active mosquito control is an essential public health function in Colorado.

Q.  Am I producing mosquitoes in my yard? 

A.  Mosquitoes require water for the immature stages to develop. Any source of standing water, big or small, can produce mosquitoes. To reduce the number of mosquitoes in your neighborhood, it is important to eliminate any standing water (from rain or irrigation) from your home and yard. Cleaning rain gutters, turning over buckets, and draining wading pools are important actions, but there are other, less obvious places that mosquito larvae can develop. Flower pots (especially if plants are being rooted), aquariums on porches, covered and uncovered boats, trash and recycle bins, and irrigation control boxes are all commonly overlooked as potential larval mosquito habitat in people's yards.

Q.  Why are mosquitoes in my grass, shrubs, and garden?

A.  Mosquitoes go to these cooler, humid, shady areas in your yard during the daytime to rest and escape hot dry air that will quickly kill them. Thinning shrubs and cutting down tall grass and weeds will reduce the harborage areas and number of mosquitoes in your yard.

Q.  Why am I getting mosquito bites during the daytime? 

A.  Some species of mosquitoes actively seek a blood meal during the daytime; others will bite during the daytime if you disturb them. It is important to remember that the mosquitoes that transmit disease in California are much more active and aggressive around dawn and dusk, especially the two hours immediately following sunset.

Q.  How far do mosquitoes fly?  

A.  Mosquitoes typically fly a few hundred yards up to two miles from the place they emerge, depending on species and environmental factors. Some common mosquitoes in Colorado are known to fly 10 miles or more.

Q.  Do all mosquitoes bite?  

A.  Only adult female mosquitoes bite. Female mosquitoes need the protein in the blood to produce eggs. Not all species of mosquitoes bite humans - some species prefer birds, large mammals, or even snakes. During the aquatic stages of its life a mosquito feeds on algae and other small organic matter. It is also important to remember that mosquitoes are not the only small flying insect that bites! Other small and biting insects are commonly mistaken for mosquitoes, including midges, no-see-ums, and black flies.

Q.  What is the most important thing I can do to reduce the chance of myself or my family getting West Nile virus or another mosquito transmitted disease?  

A.  Avoid getting bitten by mosquitoes! No amount of mosquito control can completely prevent diseases associated with mosquitoes. Taking simple precautions makes a big difference in the likelihood of getting WNV. --Eliminate all sources of standing water on your property because standing water provides a place for mosquitoes to develop. --Avoid spending time outside when mosquitoes are most active, especially at dawn and dusk.--If you go out, apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus or IR-3535. Make sure window screens are well maintained. These simple actions will help keep you and your family from getting bitten by mosquitoes that may be carrying WNV.