July 6, 2021

Mosquito Control and Disease

Preventing Mosquito Bites

One strategy to prevent mosquito bites is avoidance. But even if one were to remain indoors throughout the mosquito season, they might still encounter mosquitoes. Mosquitoes, such as the house mosquito, are adept at getting into structures to feed on the inhabitants, and also to use crawlspaces, basements and cellars as quiet spots in which to shelter themselves for the winter. It is important to keep structures in good repair, maintaining the integrity of window and door screens and weather stripping, and screening or sealing all gaps through which mosquitoes might enter, such as spaces around utility lines, vents, foundation cracks, and gaps around windows and doors.

Repellents are the first line of defense against mosquito bites. Many products provide some degree of protection against mosquito bites. However, certain active ingredients provide better protection. For many years, DEET (N,N-diethyl-meta-toluamide) has been the standard by which products are measured. When applied according to label direction, products containing 20 percent to 30 percent DEET provide protection against mosquitoes that lasts several hours. Products containing much higher percentages of DEET are available, but generally do not provide significantly longer protection.

Recently, products containing another active ingredient, picaridin, have been shown to provide a similar degree of protection, and without the familiar odor and stickiness of DEET products. A third ingredient, lemon oil of eucalyptus, is a plant-derived compound that also is capable of providing protection, though not as long-lasting as that provided by products containing DEET or picaridin.

Whatever repellent you choose, be sure to read the label directions before applying to yourself or to children. Products containing lemon oil of eucalyptus should not be applied to younger children.

Managing Mosquitos

Historically the most effective mosquito control has been larviciding, which is the application of pesticides formulated to kill mosquito larvae before they become biting adults. The Illinois Department of Public Health promotes mosquito control by advising and funding local health departments and other organizations that conduct larviciding, as well as mosquito surveillance. Surveillance includes the collection and identification of mosquitoes that helps predict mosquito and disease outbreaks and the focusing of control efforts in problem locations.


Larviciding typically involves applying pesticides containing methoprene or Bacillus thuringiensis israelensis or B. sphaericus bacteria, to water where mosquito larvae develop. As mosquito larvae feed, the Bacillus are ingested. Once ingested, a bacterial toxin perforates the mosquito’s gut, killing it. Larvicides containing the insect growth regulator, methoprene, work by disrupting the larva’s metamorphosis, preventing it from developing into an adult. The toxicity of both types of larvicide is quite low, and both are considered safe to use in waters containing fish. These larvicides can be purchased at discount and hardware stores, and lawn and garden centers for private individuals to use on their property. They can be used effectively where it is undesirable or impractical to empty the water in containers, such as water in decorative pools or horse watering tanks. Goldfish (Carassius) and mosquito fish (Gambusia) can be used for this purpose as well. Other types of larvicides include those that cover the surface of the water with thin films of liquid designed to prevent larvae from obtaining oxygen at the water’s surface.

Commercial pest control operators or municipal public works personnel who wish to apply larvicides to property they do not own must attend special larvicide training or become certified in mosquito control through the Illinois Department of Agriculture (phone 217-785-2427 for details).


The application of pesticides to control adult mosquitoes (adulticides), except for general use pesticides applied on the applicator’s property, requires mosquito control certification through the Illinois Department of Agriculture. Control of adult mosquitoes usually involves application of fine droplets of pesticides released as a space or ultra low volume (ULV) treatment from specialized truck or aerial equipment. This type of “fogging” can have a significant impact on localized mosquito populations. But while larviciding is a treatment that selectively kills mosquito larvae, adulticiding is a broad spectrum application that can kill beneficial insects as well as mosquitoes. Adulticiding is also much more expensive than larviciding and, to be effective, requires precise product and equipment selection and calibration, accurate, thorough application and timing, as well as favorable environmental conditions (generally in the evening when mosquitoes are active, temperature is between 60 F and 85 F, and there is little wind).

Adulticiding should be seen as a supplement to larviciding, to be used when mosquitoes become too numerous or when high levels of virus activity in mosquitoes threaten populated areas with disease. Mosquito surveillance, such as trapping mosquitoes and testing them for pathogens like the West Nile virus, can help determine the potential for disease transmission in an area, and this information should be considered whenever the use of adulticides is contemplated. Public notification also should take place before treatments are applied, and persons voicing questions and concerns should be answered.

In addition to the application of adulticides by fogging, some adulticides can be applied to surfaces where mosquitoes rest, such as vegetation and the exterior walls of structures. This involves applying liquid pesticides as a coarse spray. This type of application is more localized and less demanding than fogging with regard to environmental conditions and expense.

Reducing the amount of vegetation around the edges of ponds or around your home can, in turn, help reduce the amount of suitable development sites for mosquito larvae and resting places for adults, and further reduce the need to treat these areas with pesticides.

Source Reduction

Perhaps the best means of controlling mosquitoes is to deny them a place to develop. This is source reduction, the elimination of water from places where mosquitoes lay eggs. This can be accomplished by draining ponds, ditches, backwaters and lagoons, and by keeping water out of natural and artificial containers. Each of us has an obligation to make sure our properties are free of mosquito-breeding sites, such as stagnant ponds, poorly maintained swimming pools, tree holes, abandoned tires, bird baths, buckets or other debris in which water accumulates.

What Doesn't Work

Advertisers make many claims about mosquito control products. Those listed above have been proven effective when used correctly. Some that provide little or no relief from mosquitoes include:

  • purple martins and bats
  • insect electrocuting devices
  • ultrasonic and electronic devices
  • so-called “mosquito plants”
  • nutritional supplements or vitamins

In recent years, various mosquito trapping devices have been produced. Many are ineffective against mosquitoes. Some may catch substantial numbers of mosquitoes in some situations, but the traps can be expensive and their use has not been shown to lower the risk of mosquito-borne disease. Source reduction, pesticide application and the use of mosquito repellent remain the best ways to prevent mosquito bites.

If you live in the matteson area and have pest control issues you need solved please give us a call at us at or visit our site at

Mosquitoes and Disease. Mosquitoes and Disease | IDPH. (n.d.).