You may need to download the free Adobe Acrobat Reader to view these publications. We are trying to use a balanced approach to spraying. Even though the spray is reasonably safe for most people and animals, it can kill aquatic life and beneficial insects such as bees and other pollinators. So we want to spray only where we have sufficient reason to believe the benefits of spraying will outweigh the environmental risks. In addition, we want to spray only where we have reason to believe there are mosquitoes infected with the West Nile Virus.
Mosquitoes have a fairly small flying range.
Spraying areas where infected birds are found should kill most, if any, mosquitoes infected by those birds. Birds, such as crows, have very large flying areas, easily up to several hundred miles. There is no way to predict where, or if, other infected birds will fly in the county. Please remember that infected birds are not a direct danger to people. People can only become infected with the West Nile Virus if they are bitten by a mosquito that has previously bitten an infected bird.