[Pest Profile]

Culex Mosquitoes

Order/Family: Diptera/Culicidae
Scientific Name: Culex spp

Description
Mosquitoes are slender, long-legged, two-winged insects that are 1/8- to 1/4-inch long. Their wings and bodies are covered with scales, and they have long piercing and sucking mouthparts. The most notable species are the northern and southern house mosquitoes, Culex pipiens and C. quinquefasciatus, respectively, and the encephalitis mosquito, C. tarsalis.

Biology
Female southern and northern house mosquitoes lay eggs in rafts that contain up to 200 eggs on the water surface. They hatch in one or two days; development occurs in 10 to 14 days. Encephalitis mosquito adults overwinter in protected locations, and lay eggs in rafts that contain up to 300 eggs. Eggs hatch in two to three days; development occurs within 18 days.

Habits
Southern and northern house mosquitoes prefer to breed in water with high organic matter content that is contained in artificial containers. Adults readily enter structures and are vicious biters that feed only at night. They rest within structures during the day. The encephalitis mosquito is a common pest west of the Mississippi River, throughout Mexico and in Canada. These mosquitoes enter buildings in search of a blood meal. Although they feed on humans and livestock, they prefer to feed on birds.

Control
It is important to identify the species that is causing the problem as well as the breeding site(s). Because lights are beacons for mosquitoes, the attractiveness of the area should be reduced by locating lights away from the structure and directing them toward it. Sodium vapor and/or yellow bug lights should be used rather than incandescent or mercury vapor lights. Regardless of the species, the key to mosquito control is source reduction, i.e., the removal of the water breeding site. For container breeders, this is usually resolved by site clean-up. However, floodwater mosquito problems usually require the use of a larvacide.

Adulticiding with aerosols and ultra low-volume products is effective in killing the mosquitoes in the immediate area but does not provide long-term control. Residual spraying of mosquito resting sites also reduces the problem. Mosquito misting systems also can be installed where appropriate. The use of repellents should be considered. Skin repellents, such as DEET, and clothing repellents that contain permethrin are effective.

UP CLOSE
•Mosquitoes are members of the order Diptera
•Culex mosquitoes have blunt abdomens
•Northern and southern house mosquitoes are virtually identical in appearance
•Regardless of the species, the key to mosquito control is source reduction, i.e., the removal of the water breeding site
•Adulticiding with aerosols and ultra low-volume products
is effective in killing the mosquitoes in the immediate
area but does not provide long-term control
•Mosquito problems require considerable customer education because of the diversity of species, their often remote breeding sites and the ability
of many species to travel long distances