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Four Rivers Vector Control District has different methods of controlling the mosquito population dependent on the life stage of the mosquito. We control the adult mosquito population as well as the mosquito larvae.

Adult Mosquito Control

When Mosquitoes reach the threshold of 3 or more mosquitoes in 10 minutes in a specific area Four Rivers may adulticide. This must be done between last light and dawn at a temperature of 55 degrees or higher. Adulticiding is used when mosquitoes reach the threshold or in the presence of disease. Each Ultra Low Volume fog truck is equipped with a GPS tracking unit. This allows us to keep detailed visual records of each application.  We use Permethrin mixed with mineral oil at a rate of 1.2 oz. per acre. 

To report a mosquito infestation, please click the link below.

Larval Control and Surveillance

Surveillance of adult mosquitoes is a very important part of the Four Rivers Vector Control District. It is used to measure mosquito populations, which may trigger a control method, determine the efficacy of the control method, and gather them for West Nile virus testing.  We use physical "landing counts" and traps. The traps will be set with bait and dry ice. When the mosquitoes are drawn in by the carbon dioxide released from the dry ice, they are sucked into a sample net and held in the trap by a fan.  The next day we will pick them up, identify, sort them by species, and count them.  After the mosquitoes are sorted the Vector species are tested for the presence of disease.  They are then sent to Oregon State University for testing at their lab.

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