The first involves those species that lay their eggs in masses or rafts on the water's surface. Some of these species, which are found throughout the U.S., often lay their eggs in natural or artificial water-holding containers found in the domestic environment, or in naturally occurring pools. The second scenario involves mosquitoes that lay their eggs on moist soil or other substrates in areas that will be flooded with water later. After about two days, these eggs are ready to hatch, but if not flooded, can withstand drying for months. In inland areas of the U.S. where these mosquitoes breed, heavy rains and flooding can produce millions of mosquitoes in a short time.
Similar situations occur along coastal areas with mosquitoes adapted to salt marsh habitats.
Some salt marsh mosquitoes are strong fliers and can sometimes travel up to 50 miles from the breeding site. In response to these potential disease carrying pests, communities organized the earliest mosquito control programs in the eastern U.S. in the early 1900s. Eventually, other communities created similar programs throughout the country in areas where mosquito problems occurred and where citizens demanded action by local officials. Modern mosquito control programs in the U.S. are multifaceted and include surveillance, source reduction, and a variety of larval and adult mosquito control strategies. Surveillance methods include studying habitats by air, aerial photographs, and topographic maps, and evaluating larval populations.