PHONE
800-231-3236 (toll free)
707-285-2200 (office)
707-285-2210 (fax)

ADDRESS
595 Helman Lane
Cotati, California
94931-9736

HOURS
Monday through Friday
7:00AM to 3:30PM

2. THE PALE MARSH MOSQUITO (OCHLEROTATUS DORSALIS)

Ochlerotatus dorsalis' common name comes from its whitish-grey appearance: the abdomen and wings have intermixed narrow light and dark scales. Sometimes the light scales predominate. The hind legs have pale white bands overlapping the individual joints.

This mosquito is found in Asia, Europe and North America. In California it occurs along the Pacific coast and in the eastern regions of the state. Locally, it breeds along the edges of bays, marshes and lakes. It is especially frequent in the seasonally flooded marshes along the edges of the San Francisco and San Pablo bays.

A strong flyer, Ochlerotatus dorsalis often disperses 20 miles or more from its breeding sources. Unlike most other local Ochlerotatus, the pale marsh mosquito is active almost year-around. Females produce continuous broods throughout the spring and summer, with 8 to 12 hatches each year, and the last adults emerging in October. Preadult stages can be as short as 1 to 2 weeks in the warm summer weather. Populations sometimes build up to huge numbers in brackish marshes subject to prolonged spring flooding.

Ochlerotatus dorsalis is a serious pest mosquito and a secondary vector of encephalitis virus. Females prefer to feed on large mammals like cattle and horses (and man) when these are available. They are vicious biters, and so aggressive and persistent that livestock tend to move away from areas where they are numerous.