Frequently Asked Questions
Helicopter larvicide applications are deemed necessary when large areas, difficult to access areas, and/or areas with dense and/or abundant aquatic vegetation are producing mosquito larvae at densities exceeding District treatment guidelines. Treatments may be cancelled or postponed on short notice due to unfavorable weather conditions.
Materials typically used during helicopter larvicide applications include BS (Bacillus sphaericus), Bti (Bacillus thuringiensis israelensis), a naturally occurring bacteria, and methoprene an insect growth regulator. Due to the fact that the mosquito larvae may in varying stages of the developmental cycle the use of these materials enables effective control of the larvae
During a helicopter larvicide application you may hear and or see a low flying helicopter. There is no need to relocate during the treatment as only targeted bodies of water are being treated. Depending on the location of the application, recreational trails may be closed for a short time. Informational signs are posted near the application site.
Treating these areas by helicopter allows for the efficient and direct application of mosquito larvicides into large water bodies and/or water bodies with dense vegetation. Aerial application, when appropriate, can also be an option in especially sensitive habitats.