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The Aedes Vexan is a common mosquito in the Northwest.  This is a floodwater species that hatches in the river lowlands producing extremely high populations of adult mosquitoes.  These mosquitoes can travel up to 20 miles from their hatchsite in search of a bloodmeal.  This species is a vector of West Nile Virus and Western Equine Encephalitis.  The Ochlerotatus Sticticus is a secondary floodwater species with similar ecology and habits as the Aedes Vexan mosquito.

aedes vexan mosquitosticticus

Aedes Vexans                          Ochlerotatus Sticticus


Due to the vast area that is flooded during the spring freshet, the Aedes Vexan mosqutio is a primary problem for the district.  Also due to the vast amount of area that is flooded during the spring freshet the district opted to join a Aerial Application Co-op that includes Multnomah, Clark, and Cowlitz Counties.  By organizing aerial control efforts together, all  districts involved work together to keep the cost of aerial application down, and increase effectiveness of applications along our districts borders.



This is a typical setup of the helicopter with the hopper underneath to distribute BTI Granules.


Loading the helo

Loading the hopper with BTI granules with Multnomah County Vector Control


view of the hopper from helo

This is the hopper as it spreads BTI granules over mosquito habitat from the helicopter.


aerial application

Each helicopter is equipped with a navigational system that provides us with a detailed areal of where we applied granules.  This is a map showing the exact locations of our application on Sauvie Island and nearby areas.