Mosquito control is not one product. It is a set of tools aimed at different stages of the mosquito’s life, and the best programs use several at once. Here is what professionals in Florida actually use, and what each one does.

Source reduction

The first tool is not a chemical. Mosquitoes need standing water to breed, so every program starts by finding and removing it: clogged gutters, plant saucers, tarps, buckets, bromeliads and low spots that hold rain. Removing a breeding site does more than any spray.

Larvicides

For water that cannot be drained, such as ponds, rain barrels, fountains and drainage ditches, larvicides kill mosquitoes before they can fly. The main ones are:

• Bti (Bacillus thuringiensis israelensis): a naturally occurring bacterium sold as dunks or granules. It kills mosquito larvae and is harmless to fish, pets and people.
• Methoprene: an insect growth regulator that stops larvae from becoming adults.
• Surface films: thin oils that prevent larvae and pupae from breathing at the water surface.

Barrier sprays (adulticides)

This is the treatment most homeowners picture. A residual product is applied to the places adult mosquitoes rest during the day: the undersides of leaves, shrubs, shaded fence lines, under decks and around the foundation. Mosquitoes that land there die. The products are usually pyrethroids, a family of insecticides modeled on a compound found in chrysanthemums:

• Bifenthrin: long lasting on foliage, the workhorse of monthly programs.
• Lambda cyhalothrin and cypermethrin: fast acting, used in barrier and space treatments. Yes, cypermethrin kills mosquitoes.
• Permethrin: common in consumer products and clothing treatments.

A barrier spray typically lasts three to four weeks, less in heavy rain, which is why programs run monthly through the wet season.

Growth regulators added to the spray

Adding pyriproxyfen to a barrier treatment lets adult mosquitoes carry it back to breeding sites, where it stops eggs from developing. It extends the effect of the treatment beyond the sprayed area.

Traps and fogging

Carbon dioxide traps catch adults but rarely reduce a population on their own. Fogging, the fine mist you see from county trucks, knocks down adults for a few hours and is used for outbreaks, not ongoing control.

Natural and low toxicity options

Botanical oils such as garlic, cedar and lemongrass repel rather than kill and need reapplying every week or two. Bti and growth regulators are the lowest toxicity products that actually reduce numbers, which is why they anchor our programs.

What a professional program looks like

Uprooted Weed and Pest Control treats Dunedin, Clearwater, Largo and Palm Harbor yards with a monthly barrier application, larviciding of any water that cannot be removed, and a walk through for breeding sites on every visit. Treatments are applied when pets and people are indoors and are safe to walk on once dry, usually within an hour.

Related reading

• What Are Mosquitoes Attracted To? (And Why Some People Get Bitten More)
• At what temperature do mosquitoes die
• What Chemical Kills Fleas and Their Eggs?