On sunny winter days, it is not uncommon to be bothered by mosquitoes looking for a bloodmeal. This is a typical trend we see at this time every year. The Anopheles mosquito goes through the winter in a hibernating-like state resting under decks, plants, or bushes. When the warmer weather hits, the mosquito is triggered to come out of hibernation. Once they get the bloodmeal they need, they will go back into hiding not to be seen again until spring when they will begin laying eggs. Fortunately, Anopheles mosquitoes are not the type of mosquitoes that can transmit West Nile virus. While breeding and egg-laying are not occurring at this time, it is important for residents to inspect their property and drain any stagnant water in buckets, tires, flower pots, and small containers.
As the mosquitoes are actively biting only for a few hours in the afternoon, treating a property presents some problems that we don't encounter during our warmer season. Localized treatments at individual homes have proven to be largely ineffective. Mosquitoes from adjacent areas filter back in as quickly as 24 hours. Fogging large areas with spray trucks is ineffective as the wintertime mosquitoes return to secluded and sheltered hiding places at sunset where sprays cannot reach them. The District does not spray during sunlight hours because we don’t have a necessary temperature inversion, the UV rays may reduce the pesticide's effectiveness, and a wide area daytime application may pose an increased risk to non-target, beneficial insects.
To best limit the impact of wintertime mosquitoes, the District strongly recommends the following:
- Use an effective mosquito repellent that contains DEET, picaridin, or oil of lemon eucalyptus
- Limit outdoor activity in the afternoons until after dusk
- Keep doors closed and window screens in good repair
We will come out by request, only to spray inside of shops and outbuildings where mosquitoes are congregating. If you are interested in requesting service, click here.