The Madison Health Department oversees a Mosquito Control Program that consists of a number of distinct but complementary components. The Town’s Mosquito Control Program is based on an integrated pest management (IPM) approach. The primary goal of this program is to control the population of mosquitoes in order to reduce the public health threat of mosquito-borne diseases and the nuisance associated with large numbers of biting mosquitoes.
BIRD TESTING
Recently, there has been a great deal of media and public attention given to Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV), two important mosquito-borne diseases. When West Nile Virus first appeared in New England it was noted that crows (and several other bird species) were very susceptible to the virus. For several years the CT Department of Public Health operated a testing program wherein dead birds located by residents were collected by local health departments and tested for West Nile Virus by the State Health Department. The purpose of the program was to determine where the disease was spreading. At this point, West Nile Virus has spread throughout the state and so the program has been discontinued.
MOSQUITO TESTING
During the breeding season the Connecticut Agricultural Experiment Station collects mosquitoes from a trap site in Madison (and from numerous other sites in the state) and analyzes these mosquito pools for the presence of WNV and EEE. The Station issues regular press releases with the test results.
MOSQUITO MONITORING
The Town employs a mosquito control contractor to regularly inspect and if necessary, treat known mosquito breeding areas in salt-marshes and near publicly-owned properties throughout town. These inspections consist of collecting samples of standing water and counting the number of mosquito larvae and pupae present. The Madison Health Department logs complaints from residents of the incidence of heavy mosquito activity in areas throughout town and passes this information on to the contractor. All of these surveillance activities provide a picture of the abundance of mosquito populations and their life stages, as well as the identification of disease-carrying mosquitoes. This surveillance system allows population reduction activities to be targeted for maximum effect.
MOSQUITO CONTROL
The Town’s mosquito control contractor applies a biological insecticide (Bacillus thuringiensis israelensis; Bti) to portions of Town salt-marshes and Town-owned properties in which larvae are present, based on the inspections noted above. This Bti is placed weekly during the warmest part of the summer, and bi-weekly in the spring and fall. In addition, the contractor places another biological insecticide (Bacillus sphaericus) into catch basins in which there is a likelihood of mosquito breeding. The catch basins are treated several times per year, beginning in mid-June and ending in mid-September. These insecticides attack only mosquito larvae, and do no harm to other aquatic organisms. Bti is a cousin of other varieties of Bt that are commonly used in gardens to control cabbage loopers and other caterpillar pests. Bacillis sphaericus is targeted to the Culex species of mosquito, which are some of the most competent vectors of WNV and thrive in dirty waters with high organic contents, such as catch basins.
PROPERTY OWNER ACTIONS
The Town’s mosquito control program does not directly address fresh water mosquito populations on private property. That task falls to property owners and the simple act of eliminating standing water can have a substantial effect on mosquito populations. During the warmest months, water that stands for more than 5 days will probably be actively breeding mosquitoes. Mosquitoes that have been shown to most commonly carry WNV and EEE do not normally travel more than few hundred yards in their lifetime, and thus, individual actions on each property are important in controlling the potential spread of these diseases. If mosquito populations aren’t sufficiently controlled in the larval stage, large numbers may develop into adults in just a few days during the warmest weather.
PESTICIDE SPRAYING
Commercial ground-level spraying to control adult mosquitoes is the least effective and the most environmentally controversial form of mosquito management. The Town does not normally conduct such spraying. However, if a significant mosquito-borne threat to public health were detected in town, the Town Health Department and First Selectman, in consultation with the State DEP and Department of Public Health (DPH) could recommend ground-level spraying to control adult mosquito populations in targeted areas. In that case, and after alerting the public, a mild insecticide would be sprayed into the air of the affected area. The insecticide would probably be a pyrethroid, applied by a truck-mounted Ultra-Low Volume mist sprayer. This technique ensures the maximum coverage of the area with minimal insecticide. Pyrethroids are synthetic versions of natural insecticides derived from chrysanthemum flowers and exhibit very low toxicity to mammals. These insecticides break down in sunlight in 4 hours and leave no residue.
No amount of human activity will eliminate mosquitoes. Following this outline is information on actions homeowners can take to reduce mosquito populations as well as personal protective measures that can be used to avoid mosquito bites.
Outline of
Madison's Mosquito Control Program
