"Mosquito" is a Spanish/Portuguese word meaning roughly "Little Fly" - but one with a huge bite. With over 2500 mosquito species world-wide, humans may never be entirely free of them. But there are many proven ways to curb mosquito expansion.
Homeowners have some big guns they can use against their mosquito adversaries, including chemical and bacterial measures. But to use these weapons intelligently, homeowners need to understand the mosquito life cycle.
Mosquito Biology
Mosquitoes don't really crave human blood. In fact, they'd rather feast on animals like deer or small mammals. But they need blood protein to produce eggs, and, in a pinch, they'll snack on a person.
They lay eggs in stagnant or still water, either in a group (an egg "raft"), or singly, depending on species. They don't need much water - a thimble-full will do. Females are capable of laying eggs every 3rd night.
Within 24 to 48 hours the eggs hatch into tiny larvae. These "wigglers" live in their watery habitat from 4 to 14 days, siphoning air through a breathing tube poked through the water's surface tension.
During this time they gorge themselves on micro-organisms like algae and plankton. And grow. They'll molt 4 times (each molt stage is called an "instar"). The fourth molt produces a pupa.
A pupa can live for up to 4 days in water, depending on temperature. Then the pupal case splits and the adult mosquito emerges. It rests up and dries off, then takes wing - looking for a mate and a meal (not necessarily in that order, depending on species) to repeat the cycle.
Insecticides to Control Mosquitoes
Armed with the knowledge of mosquito biology, humans can choose from several potent chemical or bacterial weapons: larvicides (which attack the larval stage), or adulticides (which target the mature form).
Larvicide Choices
At the back yard scale, chemical larvicides are impractical, and are better used in community-wide systematic control programs. Homeowners have a few choices, though, for bacterial control. Mosquito Dunks are a commercial product that uses Bacillus thuringiensis israelensis (Bti). This soil bacterium is EPA registered as an insecticide. It kills mosquito larvae, but is non-toxic to humans and other wildlife.
Use Mosquito Dunks in birdbaths, ornamental pools, and flowerpots, or break up and place pieces in low spots around the property that may catch and hold water. Purportedly controls mosquitoes for 30 days. Mosquito Bits also contain Bti, but in a granular form.
Pre-Strike is another commercial product that uses S-methoprene, a growth regulator, to prevent larvae from developing into adults. Effects last for 60 days, according to Zodiac, the manufacturer. Pre-Strike comes in tablet, outdoor fogger and yard and garden spray form.
Adulticides for Mosquito Control
Several companies market misting systems for outdoor use of adulticides. These systems use 5% malathion or pyrethrins in hand-held or portable foggers and achieve some outdoor control.
Homeowners can also attack resting mosquitoes with products containing allethrin, malathion or carbaryl in broadcast sprayers that operate from air compressors or attach to the end of garden hoses. Spray the undersides of limbs and tree leaves, under porches and decks, anywhere mosquitoes are likely to shelter.
Time-released insecticide misting systems, similar in operation to an irrigation system, are also available for use at the back yard scale.
The United States Environmental Protection Agency reports that not enough research has been done on misting systems for use at the residential scale to prove their effectiveness in controlling mosquitoes or preventing the spread of diseases, including West Nile Virus. Moreover, pyrethrins and permethrin, the insecticides normally used in misters, are indiscriminate killers, toxic to all insects, even beneficial ones. Permethrin even kills fish.
Mosquito Traps
An article from the American Mosquito Control Association (AMCA) website entitled “Traps” explores the effectiveness of mosquito trap devices. Traps (such as the BG – Sentinel Trap, Mosquito Magnet, and American Biophysics ABC) exhale carbon dioxide (CO2) just like humans or animals to lure mosquitoes into the trap, where they die. They are insecticide free devices, utilizing suction to trap the mosquitoes.
Some traps have self-contained power supplies, such as propane, and can be placed anywhere on a property. Others use AC and operate at the range of an extension cord. Homeowners generally locate the devices to intercept mosquitoes before they reach human interactive areas.
The AMCA reports trapping efficiency as sporadic, depending on complex factors effecting behavioral patterns of varying mosquito species. Unfortunately, traps may wind up luring more mosquitoes into an area than they can catch.
Traps can also be fairly expensive. For continued effectiveness, an on-going maintenance program is a must.
At best, independent mosquito control methods - whether chemical insecticides or bacterial controls operating at the larval or adult stages, misters or trapping devices - can only control a portion of the mosquitoes plaguing an area. Source control (eliminating standing water) is critically important, as are introducing predators like bats, birds and dragonflies. Some electrical and mechanical control devices are also available, as well as a variety of repellents and personal controls.
Mosquito control weapons are constantly improving. By keeping up with new developments and utilizing methods appropriate to the back yard scale, homeowners have a fair chance of using their properties in mosquito-free comfort and safety.
Richard Freeland - Hi! Glad to meet you. I'm a registered landscape architect in Georgia, specializing in sustainable land planning, garden design, and ...
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