Larvicides are materials which kill immature mosquitoes before they hatch out of the water and become a nuisance to people. Our program uses several different types of larvicides depending upon the situation that is encountered. Bti or Bacillus thuringensis variety israeliensis is a natural soil borne bacterium discovered over 40 years ago. It acts by creating a crystal protein in the mid gut of mosquito larvae which causes mortality. It is highly selective to mosquitoes with little environmental impact. This bacterium is inoculated onto ground corn cob medium and applied aerially or by hand seed spreaders. B. sphaericus is quite similar to Bti, but has a longer residual action and performs better in highly organic environments like sewage lagoons. The method of application is also identical to Bti. Abate 5% Is an organophosphate insecticide imbedded in a plaster pellet. This pellet carrier releases the substance over a period of time to control larvae. It is applied by seed spreader to scrap tires or other artificial containers that do not have a free exchange of water with the surrounding environment.
Golden Bear and BVA Oil are the pupacided utilized by TCMA. They consist of a highly refined mineral oil with a surfactant added. This causes the substance to spread out in a thin film on the surface of a puddle. Pupae require air and this layer prevents their respiration which in turn causes mortality. Mosquito pupae do not feed and since larvicides must be ingested, this is the only way to eliminate mosquitoes during this life stage. The film is subject to photodegredation in sun light and is gone in a day or two.
Biomist 4-4, Evoluer 4-4 and Perm- X UL 4-4 are materials that may be used in the truck mounted units. It is a synthetic pyrethroid that provides better control in cooler temperature environments. Truck mounted ULV units produce very small droplets. The size of these droplets are large enough to be lethal to mosquitoes.