Psorophora columbiae (Dyar and Knab)

Reproduced from Wing Beats of the AMCA, the official publication of the Florida Mosquito Control Association. Please use the following citation when referring to this article:

Meisch, M.V. 1994. The dark ricefield mosquito Psorophora columbiae. Wing Beats, Vol. 5(1):8.

DR. MAX MEISCH

The Dark Ricefield Mosquito Psorophora columbiae

Importance

In large numbers, they have been reported to kill livestock! Well documented studies have shown severe losses in weight gain and milk production resulting from the bloodfeeding activity of this mosquito. Certainly, Psorophora columbiae (Dyar & Knab) causes extreme annoyance to people. The mosquito is an important vector of Venezuelan equine encephalitis and anaplasmosis in cattle.

Geographic Distribution

Psorophora columbiae, formerly known as Ps. confinnis, 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.

Identification

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. Both pre and post spiracular bristles are present. The first segment of the hind tarsus is brown with a white ring in the middle. The wings are speckled dark brown and white. The larva has a pecten of 3-6 widely spaced teeth.

Biology and Habits

Eggs are deposited on moist soil which is subject to flooding by water from rainfall or irrigation. The incubation period is about 3-5 days in the rice growing areas of Arkansas. The larvae mature rapidly during the hot summer, often developing from first instar to pupae in as few as 3.5 days.

Associated Mosquitoes

Associated mosquitoes include other Psorophora and Aedes species. In rice fields, Anopheles quadrimaculatus is commonly collected with Psorophora columbiae. Eggs overwinter and hatch in the spring when day length and water temperatures become optimum.

Larvae

The larvae develop in temporary shallow freshwater pools and puddles where there is vegetation. The larvae may occasionally be found in slightly brackish water. Ideal sites for Production of larvae are ricefields, grassy roadside ditches, and grassy swales.

Flight Range

The normal flight range of this mosquito is at least 6-8 miles; however, much longer distances have been recorded. The mosquito is readily attracted to light, and the New Jersey light trap is commonly used to monitor populations.

The females are furious biters in day or night. Hosts include any warm blooded animal; however bovine blood seems to be preferred.

Dr. Meisch is a Professor of Entomology at the University of Arkansas, Fayetteville, Arkansas.


Center for Vector Biology