Mosquitoes are the No. 1 family of insects with regard to economic and medical importance. Mosquitoes exhibit complete metamorphosis: egg, larva, pupa and imago (adult). The first three stages are aquatic; in fact, development can be successful just in damp soil.
The adult stage is when the female mosquito acts as a disease vector. Proper control includes augmentation and/or limitations of breeding sites, in conjunction with insecticide treatments. Remove all potential sources of standing water, such as birdbaths and other water-gathering objects. Adults usually are most active at dusk and dawn; however, having grown up in Florida, I can attest that this is not always true.
Adults reside on the underside of leaves and in heavy brush. Focus your insecticide treatments on these areas. Liquid applications and heavy misting are recommended.