DALY: There are no silver bullets for controlling mosquitoes

One of the most troublesome insects during summertime is mosquitoes. They are more than just an irritating annoyance because they can spread diseases.

In tropical regions of the world, they are vectors for malaria, yellow fever, dengue fever, and several others. West Nile virus and eastern equine encephalitis, although uncommon, are the primary diseases spread by mosquitoes in the southeastern United States.

Mosquitoes require a source of water to reproduce. These sources include natural bodies of water such as wetlands, ditches, lakes and man-made sources such as old tires, containers left outside and gutters on homes.

Rapidly moving waters such as creeks and rivers are not suitable as breeding sites. The female lays her eggs in the water. The larvae, which are the immature forms of the mosquitoes, hatch and appear as small “wigglers” one-eighth to one quarter inch in length. In time, they emerge from the water as adult mosquitoes. Only the females bite to suck blood to obtain proteins necessary for their eggs. The mosquitoes secrete saliva that causes the development of an itchy welt.

Mosquitoes cannot be totally eradicated from a yard. However, steps can be taken to reduce the infestation of mosquitoes around your home. Eliminate the areas where they breed if at all possible. Clean out your gutters. Remove any containers and other items that may have standing water. Ornamental water gardens can be treated with a “larvicide” which is a tablet containing bacteria that specifically targets the mosquito larvae. It is sold under various brand names such as Bactimos Briquettes, Mosquito Dunks and Mosquito Bits. The doughnut-shaped dunks will slowly dissolve and provide control for up to a month.

Several methods can keep adult mosquitoes under control. Apply insect repellents containing a chemical called DEET when outside or in high-risk areas. Wear light-colored protective clothing, long pants, shoes and socks in areas where the mosquito populations are bothersome. Also keep screen doors and windows in good repair to exclude them from homes.

Using pesticides for mosquito control should be used only as a supplement to source reduction. The chemicals can be applied by a number of methods, but an outdoor aerosol fogger is the most common. Fogging the air around your home during the evening and nighttime hours is the most effective since mosquitoes are most active at this time. Residual insecticides such as malathion and those containing permethrin can be applied to shrubbery, ground covers, underbrush and other places where mosquitoes rest during the heat of the day.

However, relief is only temporary, and applications will need to be repeated. Burning mosquito coils can give relief from the insects, but only in the immediate area. Some of the products on sale for mosquito control are not always as effective as they claim. Mosquito plants, garlic, herbal remedies and ultrasonic devices are not effective in controlling mosquitoes. Traps using light or carbon dioxide will attract more mosquitoes than they kill, thus increasing the number of mosquitoes in the area.

A few simple actions can help reduce the nuisance effects of mosquitoes. While they cannot be totally eradicated from an area, their impact can be minimized.

Timothy Daly is an Agricultural and Natural Resource Extension Agent with Gwinnett County. He can be contacted at 678-377-4010 or tdaly@uga.edu.