Summary of Mosquitoes, Napa County Mosquito Abatement District


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Summary of Napa County Mosquitoes
Scientific Name	Common Name	Habitat/Ecology	Hosts	Vector Potential/Diseases
Aedes bicristatus		One of the earliest appearing spring species. Larvae found in shallow margins of pools, ditches, etc. with heavy emergent vegetation.	Not very aggressive but will occasionally bite humans.	Unknown
Aedes dorsalis	Summer Salt Marsh Mosquito	Larvae found in brackish and saline water (e.g.. Intertidal marshes and margins of bays and lakes). Eight or more generations per year for tidal populations.	Bovine, equine and will readily bite humans.	California Encephalitis virus has been isolated from a Utah population.
Aedes nigromaculis	Irrigated Pasture Mosquito	Larvae form clumps along grassy margins. Associated with intermittently flooded pastures. Can have 10 or more generations per year.	Will readily bite humans and large domestic mammals.	Considered a potential threat for arbovirus transmission. Lab tests show this species can vector Western Equine, St. Louis Encephalitis and Japanese B encephalitis viruses.
Aedes sierrensis	Western Treehole Mosquito	Larvae found in treeholes and containers that have a lot of leafy sediment. Eggs hatch with initial fall rains and when dissolved oxygen is less than 0.25 PPM. Over winter as larvae with adults present from February - July.	Vicious biters of humans and other large mammals.	Primary vector of Dog Heartworm. Lab tests show this species capable of transmitting the Western equine encephalitis virus.
Aedes squamiger	Winter Salt Marsh Mosquito	Eggs hatch late fall and winter following high tides and heavy rains. Adults emerge end of February through April and bite through early June. Univoltine.	Humans and large domestic animals	Unknown
Aedes washinoi	Washino's Willow Pool Mosquito	Larvae found in ditches, ponds, willow groves, berry vine filled depressions and densely shaded water sources.	Humans and large mammals	Unknown
Anopheles franciscanus		Larvae found in slow moving streams and pools of water containing rich growth of green algae and exposed to good sun. Over winter as adults. Peak biting activity is dusk and dawn. Flight range is less than one mile.	Primarily mammals	Main Drain virus has been isolated from a San Diego population. Avian Malaria was found in a Kern County population.
Anopheles freeborni	Western Malaria Mosquito	Larvae prefer clear, fresh seepage water in sunlit or partly shaded pools. Also found in rice fields and roadside ditches with grass. Over winter as adults. Peak biting activities is dusk and dawn. Flight range is up to 10 miles from its breeding site.	Primarily mammals, will aggressively bite humans when encountered.	Most important vector of Vivax Malaria in California. Also a vector of Myxoma virus of rabbits. St. Louis Encephalitis virus was isolated from a Sacramento population.
Anopheles occidentalis		Larvae found in ponds, creeks, streams, swamps, and seepages. Peak abundance in May and July. Over winter as both adults and larvae.	Rarely bites humans. Preference for bovine and equine blood.
Anopheles punctipennis	Woodland Malaria Mosquito	Larvae mostly found in clear, shaded pools along creeks and streams in foothill areas. Peak biting activity is daytime and dusk. Flight range know to be more than one mile.	Prefer large mammals. Will readily bite humans when encountered.	Has successfully transmitted Vivax Malaria. Has been reported as a vector of dog heartworm.
Culex apicalis		Larvae found in cut-off pools along woodland watercourses and roadside ditches, Larvae present April through December. Over winter as adults.	Amphibians, reptiles and passerine birds.	Unknown - presumed none due to feeding preferences.
Culex boharti	Bohart's Culex Mosquito	Larvae found along the edges of slow moving streams or isolated pools of streams in open to partly shaded areas.	Amphibians.	Unknown
Culex erythrothorax	Tule or Cattail Mosquito	Larvae found in tule swamps and ponds. Peak biting activity occurs in shaded or heavily vegetated areas during daylight hours and dusk. Flight range is less than two miles.	Primarily birds and small mammals. Will bite humans if available.	Western Equine and St. Louis Encephalitis virus, and Turlock virus have been isolated from California populations. Calif. Encephalitis virus has been isolated from Utah populations.
Culex pipiens	Little House Mosquito	Larvae prefer polluted or foul water high in organic content. Can occur in fresh water but not common. Found in artificial containers, storm drains, wastewater ponds, sumps, septic tanks, water under houses, etc. Peak biting activity occurs at night. Flight range is less than one mile.	Primarily birds. Will bite humans and pets if available.	Western Equine and St. Louis encephalitis viruses are present in California populations. Has also been known to vector Avian malaria.
Culex stigmatosoma	Banded Foul-Water Mosquito	Larvae found in both foul and slightly foul water from natural and artificial pools, storm drains, pastures, man-made containers, cesspools and wastewater ponds. Adults over winter in stumps and burrows. Peak biting activity occurs at night. Flight range less than 10 miles.	Birds and mammals when available and humans when available.	Western equine and St. Louis Encephalitis viruses and Turlock virus have been isolated from California populations. Is the primary vector of Avian malaria in Kern County.
Culex tarsalis	Encephalitis Mosquito	Larvae can be found in most fresh and brackish water sources. Can tolerate coastal marsh water with salinities up to 10 ppt. Not common in polluted water. Adults rest during the day in manmade shelters, animal burrows and treeholes. Peak biting activity occurs at night. Flight range 10-15 miles.	Birds, mammals and humans when available.	Primary vector of Western Equine and St. Louis Encephalitis viruses. It is also a vector of Avian malaria. Has been associated with Turlock, Hart Park and Lokern viruses.
Culex thriambus		Larvae are found in rock pools, isolated ponds and hoof prints along streams and creeks. Also in grassy roadside ditches.	Prefer passerine birds.	Unknown
Culiseta incidens	Fish Pond Mosquito, Cool Weather Mosquito	Peak populations occur during the cooler months of the year. Larvae can be found in a wide range of fresh and brackish water habitats including isolated creek pools, artificial containers, fish ponds, abandoned swimming pools, water gardens, etc. Peak biting activity in shaded places and at night. Flight range is less than five miles.	Domestic mammals and humans.
Culiseta inornata	Winter Marsh Mosquito	Primarily a late fall through spring mosquito. Larvae found in a wide range of habitats including marshes, seepages, ditches, canals ponds, etc. Larvae can tolerate water with a salinity up to 26 ppt. Biting activity on overcast days, dusk and at night. Flight range is less than five miles.	Prefer large domestic mammals. Will bite humans if available.	Have found Western Equine Encephalitis virus in Washington populations. Cache virus has been found in Utah and North Dakota populations.
Culiseta particeps		Larvae are found in small cut-off pools of streams and the shallow margins of Typha sp. Filled pools in wooded and semi-wooded habitats.	?	Unknown

NAPA COUNTY MOSQUITO ABATEMENT DISTRICT

P.O. Box 10053 ~ American Canyon, CA 94503 ~ 707-553-9610

Eva Carrender Webmaster; Page last updated 04/02/2004 05:08 PM