Integrated Mosquito Management

Source reduction is the most effective and environmentally friendly form of control. It can be defined as the elimination of mosquito production sites, and it is often an effective and long-term solution for mosquito control. In addition, it also reduces or eliminates the need of other elements of integrated mosquito management. Source reduction can include any or all of the following: creating and maintaining ditches and/or retention ponds, removal of containers such as tires, and the drainage of flooded areas. Mosquito control-related sanitation efforts are best accomplished by the citizens of Dare County and can prove to be effective at improving residential life around their home sites. Residents are encouraged to:

Dispose of containers around homes that may store water such as tires, old plastic containers, and discarded pools·
Clean clogged gutters on a regular basis
Drill holes in the bottom of trash receptacles
Drain irrigation pipes, standing water in irrigated pastures, and clogged ditches in rural areas

Larviciding is the biological or chemical control of mosquito larva. At its infancy, mosquito larvicides primarily consisted of the treatment of mosquito-infested waters with kerosene or Paris Green. Today, mosquito abatement programs use a variety of products to suppress mosquito larvae populations. Most of the larvicides used by Dare County consist of microbial insecticides (Vectobac and Vectolex products). Microbial insecticides are highly selective for mosquito and midge larvae and result in the rupturing of the larva midgut, and the larvae usually stop feeding within hours and die within 24-48 hours. Dare County also uses surface films (Agnique MMF) to control larva populations. These larvicides reduce surface tension, making it difficult for the larva, pupa, or emerging adults to attach to the water’s surface and they drown. Surface films can persist up to 14 days and has little effect on non-target organisms when applied according to the label. Insect growth regulators (Altosid products) are the third larvicide used by Dare County. Insect growth regulators (IGR’s) prevent the normal maturation process of an insect by interfering with the development of the adult. Essentially, IGR’s prevent mosquito larva from emerging as adults. When used according to the label, IGR’s can remain effective in standing water for 150 days. Excellent results have also been obtained in areas that dry out and are reflooded. IGR’s used in the control of mosquitoes according to label instructions poses little risk to humans, nontarget organisms or wildlife.

To report standing water on or near your property that you would like treated, please call (252)475-5885.

Adulticiding is the application of chemicals through truck mounted ULV (ultra low volume) sprayers that dispense very fine aerosol droplets that stay aloft and kill mosquitoes on contact. The three adulticides used by Dare County are permethrin based; which is one of three "synthetic pyrethroids” available. Pyrethroids are man-made pesticides that mimics a natural product made from chrysanthemum plants. These pesticides have very low human/mammalian toxicity and have been used for many years around the country.

Because pyrethroids are mixed with water or oil before being applied, the amount of adulticide left on surfaces is small. Sunlight and other chemicals found in the atmosphere break up pyrethroids within one or two days. Pyrethroids also pose little threat to contaminate drinking water supplies or root structures of plant because it does not bind with soil surfaces. On the surface, pyrethroids will be broken down by the atmosphere.

Adulticiding is conducted at night during the most active time for most species, at least once a week. Additional spraying will be conducted when surveillance data indicates a need to control mosquito numbers and/or to lessen the risk of disease. A list of previous spray operations in your area can be obtained through the mosquito control department, please call (252)475-5885.

Biological Control includes the introduction of predators such as purple martins, bats, and minnows (Gambusia affinis). Introducing minnows to bodies of standing water is the most common practice of biological control that is used by many mosquito abatement programs. Biological controls are not the sole solution to controlling mosquito adult and larva populations. The best solution remains in using biological controls in conjunction with source reduction, larviciding, and adulticiding.