Natural Methods for Controlling Mosquitoes
Environmentally Sensitive Methods to Manage Biting Insect Pests
Jul 7, 2009
In the never-ending battle of human against mosquito for domination over the back yard, there's good news and bad news. First the bad news: mosquitoes can never be totally eliminated. There are too many species, too many variables in breeding and behavior, too few tried and true control methods.
Now the good news: there are weapons in the homeowner's arsenal that, if unable to totally eradicate this pesky biting insect, will at least check her expansion and leave the homeowner in possession of the field.
Mosquito Facts
Tom Floore of the Public Health Entomology Research and Education Center, Florida Agricultural and Mechanical University, reports that there are approximately 2500 mosquito species world-wide. Many species are responsible for the spread of diseases like malaria, yellow fever, dengue, encephalitis, and West Nile virus.
The female is the biter, needing a periodic blood meal to produce eggs. Fortunately, humans are not the meal of choice. Mosquitoes prefer horses, cattle, deer, small mammals, birds - even some reptiles - over man. Unfortunately, they'll feed on humans when nothing else is available, and can make outdoor living miserable.
Natural Mosquito Control
In the human-scale environment of the back yard, mosquitoes can be controlled by various natural methods that don't include chemicals. Fish, bats, bugs and birds are valid wildlife controls that may make a dent in back yard mosquito populations - or may not. There are many variables involved.
Insect Predators of the Mosquito
Natural mosquito predators include other insects. Dragonflies are one of the most efficient insect predators of mosquitoes. Homeowners owning ponds can plant bulrushes and cattails in the shallows to attract dragonflies. Once established, dragonflies will send out forays against their mosquito prey; they feed on the wing.
The larvae of the Toxorhynchites mosquito eats other mosquito's larva, as many as 40 per day - and the adult eats only nectar. It won't feed on humans.
Bats and Bat Boxes
Bats are popular mosquito control agents, and many homeowners have placed bat boxes on their property to woo bats, hoping these winged mammals will chow down on a mosquito banquet. Dr. Robert Corrigan, in a September 1997 article published in Pest Control Technology magazine entitled "Do Bats Control Mosquitoes?", explains why this may be a forlorn hope. "Bats may be both opportunistic and selective in their feeding," Dr. Corrigan states, "and several factors are involved as to which specific insects may be consumed in the greatest quantity."
Bats are as likely to feed on beneficial insects as they are "bad bugs", like mosquitoes. In fact, the American Mosquito Control Association claims that studies show less than 1% of the gut contents from bats contained mosquitoes. Beetles, wasps and moths were prevalent.
Dr. Corrigan cautions that insects like mosquitoes number in the hundreds of millions, and the number of mosquitoes taken by bats are inconsequential. Further, bats are efficient feeders. To conserve energy, they will try to take as many insects as close to their roost as possible - and the larger the insect, the more nutritional value for the bat.
Though they might not be the voracious mosquito eaters of popular myth, bats do play a beneficial role in controlling the overall population of all insects, along with other insectivorus animals, and Dr. Corrigan thinks that homeowners should encourage the establishment of bat populations.
Purple Martins as Mosquito Controllers
Another misunderstood mosquito predator is the Purple Martin. Many homeowners have constructed martin "condominiums" to attract this bird, as it has a reputation as an efficient mosquito feeder. Actually martins, like bats, are opportunistic feeders. They'll take dragonflies as soon as they'll eat a mosquito.
Ornithologist James Hill, founder of the Purple Martin Conservation Association, says that martins don't come close to controlling mosquitoes, taking an insignificant 0 to 3%. A 3-year PMCA study on diet samples taken from adult martins bringing insects to their chicks revealed, among 350 samples, not one mosquito.
The PMCA advises homeowners construct martin houses to provide quarters for martins, attracting them for their aesthetic and educational value instead of just their insect eating abilities.
Mosquito Fish
While it may be difficult to naturally control mosquitoes once they become adults, they can be attacked while they're most vulnerable. Several species of fish can help homeowners who own ponds to control these insect pests in the larval and pupal stage.
Adult mosquitoes require still or stagnant water in which to lay their eggs, and an ornamental pond is a perfect breeding ground. Mosquito eating fish like Gambusia are adept at feeding on mosquito larvae and pupae, and thrive in fresh water. Guppies and minnows will also work, as well as some goldfish species. Even catfish and bass play a part.
Recruiting birds, bats, fish and beneficial insects may or may not make an appreciable difference in the war on mosquitoes, but it's worth the effort. And the aesthetic and spiritual benefits of attracting wildlife to the back yard make up for whatever mosquito eating inefficiencies they might bring to the table.
There are other steps homeowners can take to control mosquitoes. Chemical and bacterial methods work in certain situations. Mechanical and electrical devices purported to trap or kill mosquitoes have appeared on the market, with varying degrees of success. And one of the most efficient methods of curtailing the mosquito population is probably the simplest and most cost efficient - eliminating sources of standing water.
And, if all else fails, effective mosquito repellents are available.
Think of natural controls as one of many tactics in the war on mosquitoes, homeowner's "environmental allies" in the fight to re-take the back yard.
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