Standing water, used by mosquitoes as breeding sites to lay their eggs, probably is the biggest environmental obstacle to mosquito control. So before using insecticides, manage this problem for better overall control. Identify mosquito breeding areas such as birdbaths and small ponds. Even seemingly insignificant items like plant saucers, water collected under outdoor faucets, protective tarps, full gutters, water around the air-conditioning condenser — even pet water bowls — can be used for mosquito breeding. Don’t overlook low spots in the yard, or even holes in trees.
A yard with trimmed grass and landscaping also offers fewer dark, damp spots for habitation than a less-manicured yard. Advise the homeowner on how to deal with these situations, and eliminate these and any other potential breeding areas as best you can. Augmenting the environment can help reduce populations significantly.
After you’ve tackled the environmental issues, it’s time for insecticide maintenance. Mosquitoes tend to be most active in the early morning and early evening. Spray the underside of bushes and shrubs during late morning, when adult mosquitoes are resting.
Mosquito work can be good as an ad hoc add-on service, but it might be best to issue a separate contract. Expect to visit the property at least every two to three weeks.