Controlling mosquitoes

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With the moist summer we’ve had in Kentucky, mosquitoes have had a prime environment to flourish and become a prevalent pest. They can make your life downright miserable. Many recreational and work activities have been ruined by the constant annoyance and irritation mosquito bites inflict.
Some species can transmit serious diseases. While more than 50 mosquito species can be found in Kentucky, only a few are a significant nuisance and/or public health threat. It’s important to know where mosquitoes breed and what you can do to reduce their numbers in and around your home and to protect yourself from bites.
Unfortunately, there is no easy solution for managing mosquitoes. Countless products on the market claim to be effective and easy to use, but few have appreciable value in lessening the annoyance and incidence of bites. Unlike most insects found around homes, mosquitoes are pervasive outdoor pests. There are limits to what we can do to minimize their abundance. Mike Potter and Lee Town-send, Univ-ersity of Kentucky Extension Entomologists, offer some helpful tips in combating this pest.
The most effective way to reduce the number of mosquitoes around your home is to find and eliminate their breeding sites - standing water. Adults of some mosquito species remain near their breeding site. Others can travel long distances, even up to several miles. Because of this, problem mosquitoes may come from breeding sites some distance away.
Regardless of recent weather patterns - wet, dry, warm or cool - there are plenty of potential places in which mosquitoes can develop. A neglected bird bath, swimming pool or clogged rain gutter can produce hundreds of new mosquitoes in a just a few days. Trees uprooted by storms leave soil depressions that collect seepage and rainwater. Large areas of standing water, such as from swamps, sluggishly moving streams or ditches may require efforts beyond those of individual property owners. The UK specialists make a good point. A few months back we moved my daughter-in-law’s horses to another pasture and didn’t empty the water trough only to discover, several days later, thousands of mosquito larvae swimming around in it!
However, there are effective steps you can take to minimize mosquito breeding on your property:
Dispose of old tires, buckets, aluminum cans, plastic sheeting or other refuse that can hold water. Empty accumulated water from trash cans, boats, wheel barrows, pet dishes and flower pot bottoms. If possible, turn these items over when they are not in use.
Clean debris from rain gutters and unclog obstructed downspouts. Clogged rain gutters are one of the most overlooked breeding sites for mosquitoes around homes. Remove any standing water on flat roofs or around structures. Repair leaking faucets and air conditioners that produce puddles for several days.
Change water in bird baths and wading pools at least once a week and keep swimming pools cleaned and chlorinated. Ornamental pools can be aerated or stocked with mosquito-eating fish. Aeration/water movement helps because mosquitoes prefer quiet, non-flowing water for egg laying and development.
Fill or drain ditches and swampy areas and other soil depressions. Remove, drain or fill tree holes and stumps with mortar or sealant to prevent accumulation of water. Eliminate standing water and seepage around animal watering troughs, cisterns and septic tanks. Be sure that cistern screens are intact and that access covers fit tightly.
Irrigate lawns and gardens carefully to prevent water from standing for several days.
You can keep mosquitoes out of your home by keeping windows, doors and porches tightly sealed and insect screens in good repair. The occasional mosquito that may enter can be eliminated with a fly swatter. Aerosol foggers and other indoor insecticides labeled for mosquitoes, gnats and other flying insects seldom provide relief.
While some mosquitoes are daytime biters, most are more active in the evening. Staying indoors at dusk and during evening hours will lessen the chance of being bitten. Long-sleeved shirts and pants will provide protection when outdoors, but bites can still occur through thin clothing and to exposed skin.
Topically applied mosquito repellents will help to prevent bites when spending time outdoors. The most effective mosquito repellents contain the active ingredient diethyl-meta-toluamide (DEET). The higher the percentage of DEET in the product, the longer the protection lasts. Low percentage formulations are available for use with young children.
Non-DEET containing repellents may provide some relief, but generally to a lesser degree and for shorter duration than DEET products. It is often desirable to apply insect repellent on outer clothing as well as the skin. Always read and follow directions on the container. You should not apply mosquito repellent to the hands of young children, and you should wash treated skin with soap and water after returning indoors.
Many consumer products claim to attract, repel or kill mosquitoes. Most of these devices do not appreciably reduce mosquito abundance or incidence of bites or are unproven. Electrocuting devices or “bug zappers”, using ultraviolet light as an attractant, are generally ineffective in reducing outdoor populations of mosquitoes or their biting activity. Studies indicate that mosquitoes make up only a tiny percentage of the insects captures in such traps. The majority are moths, beetles and other harmless night flying insects.
Other types of mosquito traps use carbon dioxide, warmth, light and various chemicals as attractants and claim to capture tremendous numbers of mosquitoes. Such devices often cost hundreds of dollars and some sell for more than $1,000. Performance claims to the contrary, such devices seldom have been shown to actually reduce populations of biting mosquitoes on a property, or the incidence of bites. In some situations they could even attract more mosquitoes into the area you hope to protect.
Citronella oil does have mosquito repelling properties, and the scented candles can provide a degree of protection. For maximum effect, use multiple candles placed within a few feet of where people are sitting. A single candle at the center or edge of a picnic blanket probably won’t provide much benefit other than atmosphere.
Bats and certain types of birds (purple martins) often are cited as effective natural agents for managing mosquitoes. Conservation groups and articles in nature magazines often suggest building bat and bird houses to promote nesting and to protect against mosquitoes. However, mosquitoes make up only a small portion of their natural diet. Much like “bug zappers”, they capture all kinds of flying insects. Efforts to colonize and conserve these animals should not be done solely with the intent of significantly diminishing biting mosquitoes. When it comes to managing mosquitoes, a good rule of thumb is if the device or method sounds too good to be true, then probably it is.
For more information, contact the Trimble County Cooperative Extension Service at 502-255-7188.
Source:  Mike Potter and Lee Townsend, extension entomologists
Educational programs of the Kentucky Cooperative Extension Service serve all people regardless of race, color, age, sex, religion, disability or national origin.

Michael Pyles is Trimble County’s Cooperative Extension agent for agriculture.