Every biting mosquito was a larva a week ago, floating in standing water somewhere near you. The adult population you see and feel in the evening is the result of breeding events that happened throughout your yard over the previous week or two. Understanding that cycle changes how you approach mosquito control: clearing the breeding water is not a nice-to-do; it is the most direct way to reduce the adults that show up at dawn and dusk.
Quick answer
Mosquito eggs and larvae require standing water to develop. A female mosquito can lay 100 to 200 eggs on a water surface, and larvae can develop into biting adults in as little as seven to ten days during San Antonio's hot summers. Eliminating or treating standing water on your property is one of the most direct ways to reduce the adult mosquito population, because you are cutting off the next generation before it ever reaches the air.
Want this handled for you?
Want a technician to walk your property, identify the breeding sites you are missing, and treat the ones that cannot be drained? Schedule a mosquito inspection with Mosquito Guard Pro.
The Mosquito Life Cycle From Egg to Adult
Female mosquitoes lay eggs on or near the surface of standing water. Depending on species, eggs may be laid singly on the water surface, in floating rafts, or on moist soil at the water's edge that floods later. Eggs hatch into larvae within a day or two in warm temperatures.
Larvae are aquatic, visible as small wriggling creatures just under the water surface. They breathe through a siphon tube at the rear and spend most of their time feeding on microorganisms. Larvae develop through four stages (instars) before entering the pupal stage, which lasts a few days and produces the adult mosquito.
In San Antonio's peak summer heat, the entire cycle from egg to adult takes seven to ten days. In cooler weather it slows to two to three weeks. The practical takeaway: a container that collected rainwater this week can be producing biting adults by next week.
What Breeding Sites Actually Look Like
The most obvious breeding sites are containers with standing water: flowerpot saucers, unused planters, birdbaths that have not been refreshed, buckets left out, toys and play equipment that collect water in recesses, and tarps bunched on the ground. Gutters clogged with debris hold water long after rain ends and are one of the most productive mosquito breeding sites on residential properties.
Less obvious sites include the depressions in lawn areas that stay wet after irrigation, water that pools around AC condensate drain lines, low-lying areas behind fence lines, tree stumps with hollow depressions, and the rims of garbage cans that do not drain. In San Antonio neighborhoods adjacent to drainage channels, the channels themselves are major breeding habitat, but local flood control districts typically manage those.
The Eliminate or Treat Approach
The first priority is elimination: dump, cover, or remove any water-holding item that does not need to stay. This is a weekly task, not a one-time cleanup. San Antonio gets frequent summer afternoon storms, and any container left outdoors will collect fresh water after each one.
Some water cannot be drained: birdbaths you want to keep, decorative water features, rain barrels, retention areas that are meant to hold water. For standing water that will not be removed, biological larvicides are an effective option. The most commonly used is Bacillus thuringiensis israelensis (Bti), a naturally occurring bacterium that kills mosquito larvae when ingested but is harmless to other wildlife, fish, pets, and people. Bti is available in tablet form (often sold as Mosquito Dunks) for home use, and professional applications are more concentrated and longer-lasting.
How Breeding Control Fits Into a Professional Service
A professional mosquito treatment always includes a breeding source assessment alongside the adult barrier treatment. The technician identifies the water-holding problem areas, treats standing water that cannot be drained with appropriate larvicide, and flags structural drainage issues for the homeowner.
Removing breeding sources is what makes the adult barrier treatment last. If the resting adults are treated but breeding continues at full rate, the population rebuilds within a week or two. Breeding source reduction between visits, including the homeowner's weekly walkthrough to dump containers, extends the effectiveness of each professional visit.