A dry spring has given an advantage to Douglas County officials combating mosquitoes this year.According to Mosquito Abatement District Manager Krista Jenkins, a general lack of wetness has allowed her to reach breeding sites, typically inaccessible, earlier in the season."We're pre-treating all known breeding sites for larvae with a dry chemical," Jenkins said. "That's our first line of defense. If we can keep a handle on the breeding sites with the dry spray product, then it helps keep spraying for adults down to a minimum."With the start of summer, the district has been fogging adults somewhat, but substantially less than …