Operations
AMCD uses three main methods (source reduction, larvicide and adulticide) to control mosquito populations in St Johns County.
 
Source Reduction

Usually the most effective and economical of the mosquito control techniques available and is accomplished by eliminating mosquito breeding sites. This can be as simple as properly discarding old containers which hold water capable of producing mosquitoes or as complex as implementing rotational impoundment management or open marsh water management techniques which control salt marsh mosquitoes. Source reduction, also known as physical or permanent control, typically is one part of our district’s integrated pest management program. The majority of mosquito problems in your neighborhood are a result of water-filled containers you, the resident, can help eliminate. Please remove or empty small water containers; cover or empty large water containers; change pet water regularly; flush bird baths; flush potted plant saucers; cover barrels; cover or remove tires; clean out gutters; turn canoes over; cover boats; chlorinate pools, plug tree holes; store lawn equipment indoors; put fish in ponds; remove aquatic weeds; repair leaky faucets; and flush water from bromeliads.
 
Larval Control

Larvicides are natural agents or commercial products designed to control mosquito larvae and pupae. Larviciding is a general term for the process of killing mosquito larvae by applying larvicides to aquatic habitats. Larvicide treatments can be applied from ether the ground or air. Application area/sites and rates are depended on each product’s label and directions. Larvicides are categorized by their modes of entry/action on target organisms: contact pesticides (affecting the nervous system or endocrine system), surface control agents (oil products that prevent the larvae from attaching to the surface tension of water), stomach toxins (Bacillus thuringiensis israelensis, Bacillus sphaericus) and natural agents.

Natural agents are comprised of biological organisms and are termed biological control or biocontrol. Biocontrol includes the introduction of mosquito predators into the breeding habitat. Predators include fish (Gambusia spp. and others), certain mosquito species (Toxorhynchites spp.)/other invertebrate, dragonflies, and frogs. Other natural agents include pathogens like protozoan (Nosema algerae), and parasites like nematodes.

Currently, AMCD uses larvicides, such as GB-1111 (oil), B. thuringiensis israelensis (BTI), Methoprene (Altosid) to control mosquito larvae by ground application if source reduction and other physical methods cannot be applied.

 
Adult Control

Adult mosquito control methods include physical control such as using mosquito traps, toxic baited stations and using adulticides to kill adult mosquitoes. The most common forms of adulticiding are ultra low volume (ULV) and thermal fogging. All insecticide applications must be made during periods of adult mosquito activity. Whether the treatment is ground or aerially applied, it must distribute sufficient insecticide to cover the prescribed area with an effective dose. Droplet size of insecticides and environmental conditions affect the results of adultcidiing, especially the wind direction and speed.

Malathion is a general-use pesticide, is the most widely used ground applied adulticide in Florida . Also, it is used for aerial treatments. Brand names: Fyfanon (9.79 lb. AI/gal) dosages range from 18.0 (0.0255 lb. Active ingredient (AI)/ac.)-25.8 fl.oz./mi. (0.0548 lb. AI/ac.). Fenthion (Baytex), Naled (Dibrom) are used by many mosquito control districts in Florida .

Permethrin (Aquareslin) and resmethrin (Scourge) are synthetic pyrethroids used for ground applied Adulticides in Florida . Currently, the AMCD used Aquareslin and Malathion for adult mosquito control by ground ULV application. The ULV spray machine mounted in the truck or backpack sprayer or handler sprayer. Sometimes, we had contract with outside agency for aerial application. In the future, the AMCD will have aerial program for larvicide and adulticide application.