Larviciding is an ecologically safe preventive method used to interrupt the development of larvae or pupa into adult mosquitoes. CCMCD's larvicing program emphasizes targeting mosquitoes in their habitats where they reproduce. This gives us the advantage of controlling the mosquitoes before they are biting adults.
Common Methods and Products of Larval Control
Source Reduction - This is the most efficient and ecologically safe approach at controlling mosquitoes. Mosquitoes breed in standing water. Without it they can not continue their life cycle. The most common form of source reduction is dumping out containers around the home that create a habitat for mosquitoes to lay their eggs. These containers should either be dumped out every three days, or covered to prevent collecting water. When a mosquito control personnel does an around the home inspection, they commonly find containers holding water and breeding mosquitoes.
Gambusia - Another ecologically safe approach is with one of mosquito larvae's natural predators. Gambusia are species of mosquito-eating fish. CCMCD raises these fish in a fish hatchery or other nature fish breeding sites and stocks them in permanent freshwater bodies. These fish will reproduce and continue to eat mosquito larvae.
Oils and films - Oils and mono-molecular surface films are used to control pupae and late-fourth instar larvae. A small amount of this product will sheet across the surface of water and interfere with their ability to attach to the surface of the water to breathe. These products are used only when an adult emergence will occur without treatment and has little effect on other aquatic insects.
Bti - Bacillus thuringiensis israelensis, or Bti, is a naturally occurring soil bacterium. The bacterium produces proteins in a crystalline form. When the mosquito larvae eats these crystals, the proteins attack their gut wall, paralyzing the larvae. Bti has a highly specific mode of action, and is of minimal environmental concern. Bti is quickly biodegraded and leaves no residue. CCMCD uses a granular Bti and briquettes containing Bti. The Bti is applied by field inspectors on the ground or in hard to access areas using a granular spreading system on our helicopter.
Bs - Bacillus sphaericus, or Bs, is a common soil inhabiting bacterium. The bacterium produces a protein toxin that is used to control mosquito larvae. CCMCD applies Bs as a granular formulation to control mosquito larvae in highly polluted water. Bs is also used where we find the disease carrying Culex mosquito species as a residual control. Bs is nontoxic to non-target organisms.
Spinosad - Spinosad is a product derived from a naturally occurring soil bacterium and has a unique mode of action different from the other larvicides we use. Mosquito larvae are susceptible to this product by ingestion as well as by contact. The formulations CCMCD uses are classified as a Reduced Risk product by the EPA and are OMRI (Organic Materials Review Institute) Listed, enabling them to be used in and around organic agriculture. Spinosad breaks down quickly and does not bioaccumulate in the environment and has received the Presidential Green Chemistry Challenge Award.
Methoprene - CCMCD uses Methoprene which is an insect growth regulator used to control mosquito larvae. The Methoprene prevents the adult mosquito from emerging from the immature stage so that mosquito will never be a biting insect. Field inspectors use Methoprene to pre-treat areas that are known to flood and hold water during a major storm.
Equipment and Specifications
(click on a picture to view the specs)
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