TOP ELEVEN PEST- Mosquitoes
Mosquitoes- Maricopa Co. continued...
Intermittent Water Mosquitoes
or Flood Water Mosquitoes
(two kinds)
Aedes Vexans
One of the most widespread pest mosquitoes in the world. In North America, it is common in southern Canada and is found
throughout the United States, with the exception of Hawaii. They are vicious biters and are responsible for most mosquito
nuisance complaints. They are known vectors of Western Equine
and St. Louis Encephalitis. They can also be vectors in dog heartworm. (Download a short Mosquito-Borne Viruses list.)
Psorophora Columbiae
Also known as the 'Dark Ricefield Mosquito'. The females are furious biters in day or night. Hosts include any warm blooded animal; however bovine blood seems to be preferred.
Well documented studies of cattle have shown severe losses in weight gain and milk production resulting from the bloodfeeding activity of this mosquito. Certainly, Psorophora
columbiae causes extreme annoyance to people. The mosquito is a
known vector of encephalitis and other viruses. (Download a short Mosquito-Borne Viruses list.) It is a widespread pest from Florida,
where it is known as the 'glades mosquito', to New York.
Scattered populations exist across the United States westward to California. The species is found in Mexico, Central America, the Caribbean and South America to Argentina. Psorophora columbiae reaches its greatest abundance in the rice growing areas of the southwestern U. S. where astronomical numbers, similar in magnitude to the production of saltmarsh mosquitoes, may occur.
Psorophora columbiae is a large dark mosquito with white or yellowish markings. The tarsi and proboscis are dark brown and banded with white scales. The hind femora have an apical white band and white knee spots. The first segment of the hind tarsus is brown with a white ring in the middle. The wings are speckled dark brown and white.
Intermittent Water Mosquitoes
(Flood Water Mosquitoes)
Typical Breeding Sites
Irrigation or rainwater that ponds and stands for more than three days, such as over-irrigated or poorly leveled yards and pastures,
tail-water ponds, desert ponds, stock tanks, backed up washes and flood control drainage areas.
Breeding Site Selection
Eggs are laid on soil in areas where water has ponded, and they
will lay dormant until flooded...
...by water from the next rain or irrigation. Only one generation is produced per flooding. Learn more about a mosquitoes life cycle.
Adult Habits
Most active at sundown when they attack man and animals in swarms.
| Aedes Vexans
1 of 2 water intermittent mosquitoes found in Maricopa Co. |
Psorophora Columbiae 2 of 2 water intermittent mosquitoes found in Maricopa Co. |
Aedes Aegypti An exotic species of mosquito recently found in Tempe, AZ. |
Aedes Aegypti Mosquitoes
An exotic species of mosquito known as "Aedes Aegypti" has recently been found in Tempe. This mosquito, while not native to Arizona, has been
spreading into many populated areas of southern Arizona. Aedes aegypti is capable of transmitting diseases such as
dengue fever and
yellow fever.
This mosquito thrives in urban and suburban neighborhoods because backyard containers and clutter (tires, buckets, water cans, etc.)
offer ideal breeding conditions for them.
Life Cycle and Information on
Aedes Aegypti Mosquitoes
Oviposition: Takes place in the afternoon in dark-colored water containing organic material (e.g., decaying leaves) in dark-colored
containers with wide openings. Containers located in the shade are preferred. Females lay their eggs singly on the sides of the container
at the water line in batches of 30-50. Egg laying occurs over a period of several days.
Eggs: Exposure to high humidity at the water line for 2-3 days is required for larvae to hatch from their eggs. However, if the eggs
dry out before this development period, they will collapse and the embryos will die. If they remain unhatched above the water line, and the
level of humidity is sufficient to permit larval-embryo development, eggs become "cured." This means they are resistant to desiccation and
can survive for upwards of six or more months. They can also survive short periods of subfreezing weather. Later, when exposed to water,
the eggs will hatch within a day or perhaps even within minutes. The eggs do not all hatch with a single inundation, however. Instead, they hatch
in progressively smaller numbers through a succession of inundations.
Larvae: The 4 larval stages (instars) take 5-10 days for development (some texts say 5-7 days).
Pupae: Transformation from the pupal stage to the adult stage generally takes 2-3 days. Under the most favorable climatic and
environmental conditions, the entire immature or aquatic cycle (i.e., from egg to adult) can occur in as little as 10 days.
Adults: The life span for adult mosquitoes is between 2 weeks to a month or more.
Flight Range: Usually 50-100 meters or less than 1/4 mile or so. Ranges have also been expressed as 100 feet to 100 yards, and 25 to 500 yards. However, new studies
are indicating that this mosquito may be capable of flying longer distances - as far as 850 meters or half a mile or so
(see P. Reiter et al., "Short Report: Dispersal of Aedes Aegypti in an Urban Area After Blood Feeding as Demonstrated by Rubidium-Marked Eggs,"
found in the American Journal of Tropical Medicine Hygiene - 52(2):177-179, 1995).
