I have worked as a fishing guide in Western Alaska for 25 years. Clouds of mosquito's are out 24 - 7. Every year clients come to Alaska with the newest bug protection on the market. I have only seen two things work. Clothes and a head net, or DEET. I hate wearing head nets, so I use DEET. The lighter concentration sprays will work for a short time. 100% for longer periods. For white sock nats, and no see ums only large doses of 100% DEET, used often is effective. Like I tell the new guides every year. DEET is toxic, but it's better than bleeding to death.