MOSQUITO CONTROL

The purpose of an Integrated Mosquito Management, or IMM, is to protect public health from diseases transmitted by mosquitoes, protect the environment through proper use and disposal of pesticides, and to improve the overall quality of life through practical and effective pest control strategies. Cascade County Mosquito Control (CCMC) is committed to the following strategies: Education, Surveillance, Physical Control, Biological Control, Chemical Control, and Evaluation and Research.

Education and a good relationship with the public is vital to the success of a mosquito control program. CCMC will continue to seek opportunities to educate and inform the public about mosquitoes and vector-borne diseases through media outlets, public discussions, or simple one-on-one conversations. If your school, class, group, club, etc. is interested in learning more about mosquitoes and the diseases they can carry, please contact the office at (406) 454-6920.

The use of mosquito and disease surveillance in a control program is essential to making good decisions. Mosquito surveillance can be separated into larval surveillance and adult surveillance. Larval surveys involve the inspection by trained staff of any standing water, sloughs, irrigated pastures, etc. for the presence of mosquito larvae and pupae. The presence of larvae, which stage of development they are in, and the larval density for the area determines which pesticide and equipment will be used. Larval thresholds are also used when determining if pesticide is needed.

Adult mosquito surveillance involves the use of CO2 traps for the collection of mosquitoes. Those collected mosquitoes are separated to species. Cascade County regularly traps 6 species - Culex tarsalis, Aedes vexans, Ochleratatus dorsalis, Ochleratatus nigromaculis, Ochleratatus melanimon, and Culiseta inornata. Culex tarsalis is then separated into pools or samples of 10 to 50 mosquitoes. Those mosquitoes are then tested in the CCMC lab for the presence of West Nile Virus. Positive presence of the virus are forwarded to the Montana Department of Public Health and Human Services.

Physical Control involves the taking of measures to eliminate standing water. Often called source reduction, some of these proactive activities include proper irrigation techniques, draining or filling of unwanted or unnecessary ponds, and creating steep banks at water collection sites. Vegetation management is also necessary to eliminate protection and food for mosquito larvae.

The introduction or use of natural predators is a form of Biological Control. Larvae eating fish, such as Gambusia affinis and dragonfly nymphs are examples of natural predators. Biological control can also be used to describe certain pesticides such as Bacillus thuringiensis israelensis (BTI) and Bacillus sphaericus (BS). Each of these two active ingredients are naturally occurring bacteria which are specific to the control of mosquito larvae. Once ingested by a mosquito larva, the BTI or BS produces spores which rupture the gut of the larva resulting in death. The Vectobac (BTI), Aquabac (BTI), and Vectolex (BS) products utilize this environmentally safe technology. The CCMC uses these products because of their effectiveness and because there is minimal risk to non-targets.

Chemical Control is divided into larval control and adult control. For a complete list of the pesticides used by CCMC please refer to the PESTICIDES page where individual pesticide labels and Material Safety Data Sheets (MSDS) can be viewed and printed. Please contact us if you have additional questions.

Throughout the mosquito season, Evaluations are being conducted to ensure the proper use of pesticides and equipment, that employees have been trained properly, and that CCMC is in compliance with all safety measures. A complete evaluation of all aspects of the program are reviewed, updated, or changed at the end of each season. In addition to evaluating the program, Research is conducted with chemical companies in the testing of new products, assistance is given to research at the university level (currently with Montana State University), and CCMC also conducts its own research projects at the local level. All of these projects and trials not only aid the local program but also the mosquito control community throughout the world. We are proud and privileged to work with wonderful, hard working people, companies, and universities who share the same goals.