![Mosquitoes](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/featured.webp "featured image") # Mosquitoes - [Pest Library](https://hollomanexterminators.com/pest-library) / Mosquitoes Three of the four mosquito life stages happen in water, which is why the most effective thing you can do costs nothing. Tip out the standing water. A bottle cap holding rain is enough to raise a brood. ## Seasonal Timeline Summer, but the length varies sharply by region. The Gulf Coast runs five months. The Mountain West runs two. Disease risk peaks later: the CDC records West Nile diagnoses peaking in late August and early September. **Peak, Pacific Northwest, Mountain West, Midwest and Northeast**Jul–Aug **Peak, California and Southeast**Jun–Sep JanFebMarAprMayJunJulAugSepOctNovDec Summer, but the length varies sharply by region. The Gulf Coast runs five months. The Mountain West runs two. Disease risk peaks later: the… The Southwest is the odd one out. Its season is monsoon-driven, so activity surges after the summer rains rather than tracking temperature. South Florida is close to year round. ## Where They're Found All eight U.S. regions, and the CDC reports that every state in the contiguous United States has recorded West Nile cases. Three genera matter here and they behave differently: *Culex*, which carries West Nile and breeds in stagnant water, *Aedes*, the day-biting container breeder behind dengue and Zika, and *Anopheles*, the malaria genus. ## Related Pests [ Aedes Mosquitoes ](https://hollomanexterminators.com/pest-library/aedes-mosquitoes) [ Anopheles Mosquitoes ](https://hollomanexterminators.com/pest-library/anopheles-mosquitoes) [ Culex Mosquitoes ](https://hollomanexterminators.com/pest-library/culex-mosquitoes) [ Fleas ](https://hollomanexterminators.com/pest-library/fleas) [ Ticks ](https://hollomanexterminators.com/pest-library/ticks) ## Life Cycle **In summer the whole cycle takes a week or less**, depending on water temperature. That is the reason the standard advice is to change bird bath and pet bowl water *weekly* rather than occasionally. You are beating the clock, not tidying up. ![Mosquito egg raft floating on the surface of still water](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/egg.webp "egg image") ### Egg[2](#credit-2) Egg. Some species lay singly, others in rafts of 100 or more. Eggs on water hatch in a couple of days. Eggs laid above the waterline can wait months, or years, for a flood. ![Mosquito larvae hanging beneath the water surface by their breathing tubes](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/larva.webp "larva image") ### Larva[3](#credit-3) Larva, or wiggler. Four stages, all in water, all breathing air at the surface. The air tube at the tail end tells you the genus. ### Pupa Pupa, or tumbler. One to two days to adult, males first. It does not feed, which is why the common larvicide misses it. ### Breeding sites This is the real target. A yard like this is a nursery, and finding every container is most of the work. ## Identification ### Two features separate a mosquito Small, delicate, two-winged flies. Two features separate a mosquito from the things it gets mistaken for. The first is the **long slender proboscis**, the tube it uses to pierce skin. The second needs a magnifying glass: **small scales cover the wings**, which no similar fly has. ### Crane flies get blamed They do not deserve it. They are much larger, and despite the nickname mosquito hawk, they do not eat mosquitoes. Non-biting midges are the other common mix-up. ### Only females bite There is a physical reason. Males feed on nectar and fruit juice, and the CDC notes the male proboscis is not strong enough to pierce skin at all. Females need blood only to develop eggs. ### The larvae tell you the genus In the water, the larvae tell you the genus. *Culex* and *Aedes* larvae have a distinct air tube at the tail end. *Anopheles* larvae do not. ## Signs of Infestation ### Look for the larvae, not the adults By the time you are being bitten, the nursery has already produced. Wigglers hang just beneath the surface of anything holding still water, and comma-shaped pupae tumble alongside them. ### Run the container list Bird baths, buckets, plant pot saucers, old tires, soda cans, tree holes, rain barrels, clogged roof gutters, street gutters and catch basins, cooler drains, watering troughs, plastic pools, septic openings, and any pool or spa that has stopped being maintained. ### The threshold is lower than people expect UC IPM's own example is that even a bottle cap holding water can support larvae. This is why a yard inspection takes as long as it does. ### One clean-out is not enough, and here is why Container-breeding *Aedes* lay eggs just above the waterline. Those eggs survive drying for months, and they do not all hatch the first time they are flooded. Every rain re-seeds the site. ## Prevention and When to Call a Pro ### The strategy follows the biology The whole strategy follows from the biology: three of the four stages are in water, so **larval control is what works** and adult spraying is the weakest link, not the strongest. ### Weekly beats occasional Change the water in bird baths, pet dishes and watering troughs every week, which beats the egg-to-adult clock. Empty and turn over unused containers. Fill tree holes with sand or mortar. Clean gutters and downspouts. Do not overwater the landscape. ### Rain barrels are forgotten Rain barrels are the source people forget. Screen or seal every access point, keep the filters and pre-filters clear, and check regularly for cracks, leaks and failed seals around the valves. ### Bti works, with one limit Bti works, with one honest limit. *Bacillus thuringiensis israelensis* is a bacterium that kills mosquito larvae and leaves people, pets and plants alone. Mosquito Dunks last about 30 days. But larvae have to eat it, and **pupae do not feed**, so any pupae already present will still become adults. That is why a treated barrel can keep producing for a couple of days. ### Repellents, with the numbers These are the numbers that matter. DEET and picaridin are the conventional choices. Oil of lemon eucalyptus, its synthetic form PMD, and IR3535 are the CDC-recommended alternatives, though PMD is not for children under three. Protection typically lasts four hours or less. Higher concentrations last longer, but above 50 percent there is no meaningful gain, and under 10 percent you may get only an hour or two. Permethrin treats clothing and must never go on skin. ### What does not work Most of it is sold anyway. Repellent wristbands, ultrasonic emitters, electric grids, electronic repellers, the so-called mosquito plant, incense coils, vitamin B1, and brewer's yeast and garlic mixtures. Citronella candles and coils only help outdoors with very little air movement. ### Bug zappers are worse than nothing Bug zappers are worse than doing nothing. UC IPM calls them counterproductive, because many of the insects they kill are the ones that prey on mosquitoes. ### Call your vector control district Call your county mosquito and vector control district first. They exist in most of the country, they are free, and they do larval surveillance and disease testing that no private company duplicates. Then treat the yard. Two honest limits on what any yard work can achieve: adults fly several miles from where they hatched, so your neighbors' water matters as much as yours, and outdoor sprays reduce adults only temporarily with no lasting effect. That is worth knowing before you pay for one. ## Frequently Asked Questions ### Do bug zappers work on mosquitoes? No, and they can make it worse. UC IPM calls them counterproductive, because many of the insects a zapper kills are mosquito predators. Killing larvae in standing water is the method that actually works. ### How long does it take a mosquito to grow from an egg? In summer, a week or less, depending on water temperature. That is exactly why the advice is to change standing water weekly rather than whenever you remember. ### I dumped all the water and they came back. Why? Container-breeding Aedes lay their eggs just above the waterline. Those eggs survive drying for months and they do not all hatch the first time they get flooded, so every rain starts another batch. It takes repetition, not one clean-out. ### Why do mosquitoes bite me more than other people? They find you by the carbon dioxide in your breath, by air movement, by odor, and by seeing you move. Breathing harder and moving more makes you easier to find. ### How dangerous is West Nile virus? Most people who get infected never develop symptoms, and about 1 in 150 develop a neurological illness that can be fatal. The CDC records roughly 2,000 diagnosed cases a year in the U.S., more than 1,300 severe cases, and more than 130 deaths. There is no vaccine and no treatment for people, which is why prevention is the whole game. ## Photo Gallery [ ![Vintage scientific illustration of Anopheles earlei, a North American mosquito species, dorsal view](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/mosquitoes-anopheles-earlei-illustration.webp "mosquitoes-anopheles-earlei-illustration image") ](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/mosquitoes-anopheles-earlei-illustration.webp)A historical entomological plate of Anopheles earlei, illustrating the dorsal wing and leg pattern used to key out mosquito species. [ ![Antique hand-colored illustration of an Anopheles maculipennis mosquito feeding, red abdomen visible](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/mosquitoes-anopheles-maculipennis-feeding-illustration.webp "mosquitoes-anopheles-maculipennis-feeding-illustration image") ](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/mosquitoes-anopheles-maculipennis-feeding-illustration.webp)A hand-colored 19th-century plate from the Journal of Hygiene showing Anopheles maculipennis mid-feed, the abdomen visibly reddening with blood. [ ![Antique dorsal illustration of an Anopheles maculipennis mosquito with wings spread](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/mosquitoes-anopheles-maculipennis-dorsal-illustration.webp "mosquitoes-anopheles-maculipennis-dorsal-illustration image") ](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/mosquitoes-anopheles-maculipennis-dorsal-illustration.webp)A companion plate from the same 19th-century journal, showing Anopheles maculipennis from directly above with wings fully spread. [ ![Diagram of potential mosquito breeding sites around a home, including gutters, containers, and standing water](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/mosquitoes-breeding-sites-diagram.svg "mosquitoes-breeding-sites-diagram image") ](https://hollomanexterminators.com/images/pestlibrary/mosquitoes/mosquitoes-breeding-sites-diagram.svg)A labeled diagram of the standing-water spots around a typical home where mosquitoes breed, from clogged gutters to forgotten containers. ## Sources 1. [Pest Notes: Mosquitoes](https://ipm.ucanr.edu/PMG/PESTNOTES/pn7451.html) UC Statewide IPM Program, UC ANR Publication 7451 2. [About West Nile](https://www.cdc.gov/west-nile-virus/about/index.html) Centers for Disease Control and Prevention 3. [About Mosquitoes](https://www.cdc.gov/mosquitoes/about/index.html) Centers for Disease Control and Prevention 4. [Using Insect Repellents Safely and Effectively](https://www.epa.gov/insect-repellents/using-insect-repellents-safely-and-effectively) U.S. Environmental Protection Agency 5. [Bti for Mosquito Control](https://www.epa.gov/mosquitocontrol/bti-mosquito-control) U.S. Environmental Protection Agency ### Image Credits 1. Image: Adobe Stock, licensed. 2. Image: NPMA. Used under NPMA member image license. 3. Image: James Gathany, CDC via Wikimedia Commons. CC BY 2.5. [License](https://creativecommons.org/licenses/by/2.5/). 4. Image: CDC, Public Health Image Library, via Wikimedia Commons. Public domain. [Source](https://commons.wikimedia.org/wiki/File:Anopheles_earlei.jpg). 5. Image: Wellcome Collection, via Wikimedia Commons. Licensed CC BY 4.0. Resized. [Source](https://commons.wikimedia.org/wiki/File:Anopholes_Maculipennis_sucking_blood._Wellcome_L0068421.jpg). [License](https://creativecommons.org/licenses/by/4.0). 6. Image: Wellcome Collection, via Wikimedia Commons. Licensed CC BY 4.0. Resized. [Source](https://commons.wikimedia.org/wiki/File:Anopholes_Maculipennis_Wellcome_L0068420.jpg). [License](https://creativecommons.org/licenses/by/4.0). 7. Image: Christian Ries, via Wikimedia Commons. Licensed CC BY-SA 4.0. Unmodified. [Source](https://commons.wikimedia.org/wiki/File:Potential_mosquito_breeding_sites_around_a_dwelling.svg). [License](https://creativecommons.org/licenses/by-sa/4.0). ## Related Pests [ Aedes Mosquitoes ](https://hollomanexterminators.com/pest-library/aedes-mosquitoes) [ Anopheles Mosquitoes ](https://hollomanexterminators.com/pest-library/anopheles-mosquitoes) [ Culex Mosquitoes ](https://hollomanexterminators.com/pest-library/culex-mosquitoes) [ Fleas ](https://hollomanexterminators.com/pest-library/fleas) [ Ticks ](https://hollomanexterminators.com/pest-library/ticks)