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Mosquito Control - Frequently Asked Questions


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Question: Why are the mosquitoes bad around my house? What can I do about them?
Answer: Many adult mosquitoes around the home come from mosquito production sites within or near the neighborhood. To help reduce the number of mosquitoes, homeowners should eliminate or reduce standing/stagnant water on their property, especially containers like buckets, wheelbarrows, kiddie pools, bird baths, corrugated pipes, clogged rain gutters, and flower pot saucers. For larger mosquito breeding habitats like wetlands, roadside ditches, or stormwater management basins, contact the Mosquito Control Section office for your area. (See our contact information on the About Us page.) Click here for more information.  Click here to view the Mosquito Control & Your Backyard video.

Q: Why do we need mosquito control?
The Delaware Mosquito Control Section's mission is to control the state's nuisance and potentially disease-bearing mosquito populations for the purposes of protecting public health, quality of life, and economic interests.  Click here for more information. Click here to view the American Mosquito Control Association's "Why We Need Mosquito Control" video.

Q: What kinds of insecticides are used and when?
The Mosquito Control Section utilizes insecticides as an important component of its Integrated Pest Management (IPM) program.  Our IPM program involves the combination of various different control methods, including insecticides.  All of our insecticides are registered and approved by the U.S. Environmental Protection Agency and have been determined to pose no unreasonable risks to human health, wildlife, or the environment. The two basic types of mosquito control insecticides are larvicides (for larval or the immature aquatic life stage of the mosquito) and adulticides (for control of adult mosquitoes). We currently use the following larvicides: Bti, methoprene, Spinosad, and monomolecular film.  Our fog trucks apply sumithrin (a synthetic pyrethroid), and our aircraft applications use naled (an organophosphate). Click here for more information. Click here for our Spray Information page.

Q:  Why do you have to use insecticides? What other methods are used?
The Mosquito Control Section prefers, whenever practicable, to use non-insecticide control methods. There are several methods of source reduction through which mosquito-producing habitats are eliminated or mosquitoes are controlled in their pre-emergence larval stages. These methods include water sanitation and elmination of container breeding habitats, Open Marsh Water Management (OMWM), management of tidal flows and marsh water levels, and stocking of mosquito fish.  When source reduction is not possible, or practicable, insecticides are used. Click here for more information.

Q: Are mosquito control insecticides safe? Should I be concerned if I'm exposed to spraying?
The Mosquito Control Section only uses insecticides that are registered by the U.S. Environmental Protection Agency (EPA)  for mosquito control purposes. The EPA has determined through its testing and review process that when these insecticides are applied according to the label instructions, their application "poses no unreasonable risks to human health, wildlife, or the environment."  For the general public, exposure to spraying will not cause any harm.  Individuals that are hyper- or chemo-sensitive may experience mild allergic reactions and should consult a medical professional. Click here for more information.

Q: How can I find out when and where mosquito control spraying might be done?
: There are several different ways to find out when and where mosquito control spraying will be done. The most common way is through our email list server (RSS Feed). You can subscribe to the email spray announcements through the Spray Zone Notification System at (follow the instructions on the SZNS page). Spray announcements are also made on our toll-free hotline at 1-800-338-8181 and are submitted to local radio stations (that may or may not air the announcmenets). Click here for more information.

Q: What steps can I take to avoid exposure to mosquito control spraying?
To avoid exposure to mosquito control spraying, an individual can temporarily leave an area about to be sprayed or remain indoors with the windows and doors closed and the air conditioner(s) turned off during and immediately following an insecticide application. Click here for more information.

Q: How can I avoid mosquito bites?
A: The simplest way to avoid mosquito bites is to avoid areas or times where mosquitoes are most active. If you live in a mosquito-prone area, try to stay indoors during peak mosquito activity. If you can't stay indoors, wear light-colored long-sleeve shirts and pants. You may also want to use a mosquito repellant. The repellants that contain DEET are scientifically proven to be the most effective; however, there are several other repellants (such as picardin or oil of lemon eucalyptus) that may work for you as well. Click here for more information.

Q: What should I do if I find a sick/dead wild bird that might have West Nile Virus?
If you find a sick wild bird, you should contact Tri-State Bird Rescue & Research at 302-737-9543. If you find a dead bird, try to determine which species of bird you have found. The Mosquito Control Section only collects crows, blue jays, cardinals, robins, and birds of prey for West Nile virus testing. You should also assess if the bird has been dead for less than 24 hours. The testing for West Nile virus in dead wild birds requires a fresh specimen. If the bird is one of the species listed above and has been dead for less than 24 hours, you should call the Mosquito Cotnrol office for your area. Click here for more information.

Q: What are the human health symptoms of mosquito-borne diseases? What is the probability of becoming infected or sick?
Eastern Equine Encephalitis (EEE) and West Nile virus (WNV) are viruses that can cause encephalitis. Early symptoms of EEE and WNV are flu-like symptoms and include headache, mild fever, body aches, malaise, and swollen lymph glands. A more virulent infection of EEE or WNV can progress to severe headache, high fever, neck stiffness, and muscular weakness and can cause behavorial changes including stupor, confusion, and disorientation. Fortunately, scientists estimate that probably less than 1 percent of the mosquito populations that can carry this virus are infected. If you are unlucky enough to be bitten by one of the <1% of mosquitoes that are infected, you have only about a 1 percent chance of becoming severly ill. The Mosquito Control Section takes aggressive measures to reduce the frequency and intensity of mosquito populations to reduce the chances that you may get bit. If you take additional personal protection measures to avoid mosquito bites, then your chances of contracting a mosquito-borne disease are exceedingly small. Click here for more information.

Q: There are a lot of biting flies, gnats, ticks, and other flying insects around my house or yard that I don't like.  Can't Mosquito Control do something about them?
Unfortunately, the answer is NO. Our enabling State statute allows us to only take actions that control mosquitoes. We recommend that you contact the University of Delaware Cooperative Extension Service for non-mosquito pest problems. The Extension Service phone numbers are (302) 831-2506 in New Castle County, (302) 730-4000 in Kent County, and (302) 856-7303 in Sussex County.  In many cases, you might have to call a commercial exterminator or pest control company. Click here for more information.

Q: Describe the Mosquito Control Section. Who are you?
 The Mosquito Control Section is part of DNREC's Division of Fish and Wildlife and has a staff of 18 people working year-round to deal with Delaware's mosquito problems. We also hire about 15 seasonal employees every summer to meet our increased seasonal workloads. The Mosquito Control Section has three: facilities: Administrative headquarters in Dover (302-739-9917), a field operations center for the northern half of the state in Glasgow (302-836-2555), and a field operations center for the southern half of the state in Milford (302-422-1512). The Mosquito Control Section also performs Open Marsh Water Management (OMWM) and is the lead agency for the Northern Delaware Wetland Rehabilitation Program (NDWRP). Click here for more information.

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