There are two kinds of mosquito control: large, organized programs to reduce mosquito populations over a wide area, and actions an invidual can take to control mosquitoes with respect to themselves and their own property.
Organized mosquito control programs today draw on the principles of integrated pest management. An integrated mosquito control program typically includes the following measures, all guided by surveillance of mosquito populations and knowledge of the mosquito life cycle:
Since many mosquitoes breed in standing water, source reduction can be as simple as overturning an old tin can, or can be as complex as permanently draining marshes. Much source reduction is a matter of education. For example, homeowners can eliminate mosquito breeding grounds by removing unused plastic pools, old tires, or buckets; by clearing clogged gutters and repairing leaks around faucets; by regularly changing water in bird baths; and by filling or draining puddles, swampy areas, and tree stumps. Eliminating such mosquito breeding areas can be an extremely effective and permanent way to reduce mosquito populations without resorting to insecticides.
Habitat modification, such as ditching or diking marshes or manipulating daily water flows can be effective at reducing mosquito populations by disrupting the mosquito life cycle, but experience has shown that such large-scale programs can be harmful to the ecosystem if not undertaken carefully. One example of a successful approach to habitat modification, open marsh water management, involves the use of shallow ditches to connect the shallow waters where mosquitoes breed to deeper waters where natural predators live. Simply giving the predators access to the mosquito larvae can result in long-term mosquito control.
Source reduction, which incorporates physical control -digging ditches and ponds in the target marsh- and biological control; placing live mosquito fish (Gambusia) in the ditches and ponds to eat mosquito larvae.
Biocontrol is the direct introduction of predators to target mosquitoes. Effective biocontrol agents include predatory fish that feed on mosquito larvae such as Gambusia affinis and other minnows and killifish. Some other biocontrol agents that have had lesser degrees of success include the predator mosquito Toxorhynchites and predator crustaceans, nematodes, and fungi. Some public agencies also employ other predators such as birds, bats, dragonflies, and frogs, but evidence of effectiveness of these agents is only anecdotal. In particular, there is no documented study that establishes that bats or purple martins consume enough mosquitoes to significantly control mosquito populations.
Also used as biological control agent are the dead spores of varieties of the natural soil bacteria Bacillus thuringiensis, especially Bt israelensis (BTI). BTI is used to interfere in the digestion systems of larvae. It can be dispersed by hand or dropped by helicopter in large areas. BTI is no longer effective after the larvae turn into pupae, because they stop eating.
At this point larviciding oils, such as Golden Bear, can be used which increase the water tension until the pupae and larvae cannot break the surface to obtain air and therefore drown. A chemical commonly used in the United States is methoprene, considered slightly toxic to larger animals, which mimics and interferes with natural growth hormones in mosquito larvae, preventing development. Methoprene is frequently distributed in time-release briquette form in breeding areas.
Adulticide, the ground or aerial application of chemical pesticides, is less effective than the other methods of mosquito control and is generally considered a method of last resort. Nevertheless, careful application of adulticide is considered a critical part of integrated mosquito management. For example, ultra low volume (ULV) spraying of Malathion has been used in metropolitan areas like New York City to decrease the mosquito population and prevent the spread of West Nile Virus.
Adult mosquito biological control by means of birds, bats, dragonflies and frogs has been employed by various agencies.
The most effective solutions for malaria control efforts in the third world are: mosquito nets (klamboe), insecticide-laced mosquito nets, and DDT. [3] Plain mosquito nets are cheap, they are completely effective in protecting humans within the net, they do not adversely affect the health of natural predators such as dragonflies, and do not require sophisticated public health capacity on the part of the government.
The role of DDT in combating mosquitoes has been the subject of considerable controversy. While some argue that DDT deeply damages biodiversity, others argue that DDT is the most effective weapon in combating mosquitoes and hence malaria. While some of this disagreement is based on differences in the extent to which disease control is valued as opposed to the value of biodiversity, there is also genuine disagreement amongst experts about the costs and benefits of using DDT. Moreover, DDT-resistant mosquitoes have started to increase in numbers, especially in tropics due to mutations, reducing the effectiveness of this chemical.