For Release May 22, 2005

Everything You Always Wanted To Know About Mosquitoes

AGRI-VIEWS
by Chuck Otte, Geary County Extension Agent

As a follow up to last week's column, I thought I'd go a little bit more in depth on mosquitoes because there are so many myths about mosquitoes that need to be debunked! There are about 50 species of mosquitoes in Kansas. Many are native, a few have wandered in or accidentally introduced. Only females feed on blood, males survive by feeding on sugary liquids like flower nectar. Preferred hosts can change during the course of a season. One of the principal carriers of West Nile Virus in Kansas prefers feeding on wildlife in pastures and grasslands, early in the season, but by midsummer they've moved into the residential areas and switch over to feeding on humans.

Mosquitoes over winter as adults, finding nooks and crevices, both natural and manmade, to escape the bitter cold winds. Whenever we have a few days of warm weather, even in December and January, mosquitoes can become active. When spring finally does arrive the female mosquito mates and lays her eggs in water. The most effective mosquito nursery is shallow water, just a few inches deep, with emerged vegetation and very little wave action. But mosquitoes are very adept at breeding in any stagnant water including bird baths, pet watering dishes, saucers under flowerpots, old tires, plugged or sagging gutters, really anywhere that will hold water for a period of 7 to 14 days.

In the heat of summer, mosquitoes can produce a new generation, egg to biting adult, in about seven days. The eggs hatch very quickly and the larvae can become very easy to see as they wriggle about in the water, coming up for air and feeding on bits of organic matter floating in the water. Adult females are ready to bite and obtain a blood meal about two days after emerging as an adult. Some species have but one generation per year, others may have as many as four. Adults prefer to rest in grass, shrubbery and around water breeding areas. Many species are powerful fliers and are known to travel 5 to 10 miles during an evening of feeding activity. But they tend to fly quite low, rarely flying more than 15 to 20 feet above ground level, unfortunately well below the feeding range of Purple Martins or bats.

In recent years, we have become quite concerned about mosquitoes as they are the carrier of West Nile Virus. But mosquito borne diseases are nothing new. While malaria, dengue, and yellow fever are well known from the tropics, there are various mosquito-borne encephalitis infections transmitted by mosquitoes.

Controlling mosquitoes is best done by controlling breeding locations. Change water in bird baths, etc. every 3 to 4 days so they don't have a chance to complete a generation cycle. Drain water when practical or treat water with biological control products, i.e., mosquito dunks. Space spraying or fogging is extremely ineffective because it is so difficult to get the sprays to where the mosquitoes are and because the mosquitoes can travel such great distances.

Mosquito repelling plants simply don't work, nor do the electronic ultrasound devices. While mosquitoes are attracted to carbon dioxide, hence why some people receive more bites than others, the carbon dioxide generating traps may not be a good choice in Kansas and we have little evidence to justify their expense. The best approach to preventing bites is personal protection though clothing and repellents containing DEET. There are some interesting results from nontraditional products though. For more information on these, contact me at the Extension Office.

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