Mosquito protection in tough areas
July through August is the peak time for transmission of West Nile Virus in South Dakota and area residents may need to take extra precautions if required to be outdoors in areas where mosquitoes are tough to control.
South Dakota State University Pesticide Education Coordinator Jim Wilson said wearing insect repellent is always good advice for those who are required to be outdoors, especially after sundown and into the evening.
“Protecting yourself from mosquitoes during a stroll in the park, however, is a lot different from preventing bites when you are walking fields or working in other mosquito-infested areas,” Wilson said. “Mosquitoes rest in humid, shady areas during the heat of the day, but if they are disturbed, they can be a pest at any time.”
Covering as much skin with loose fitting clothing and wearing insect repellent is still a good recommendation, but may not be enough when you are in heavy mosquito-infested habitat.
“Consider using a permethrin treatment designed to be used on clothing that will be worn in the infested area. This type of permethrin is formulated to bind to the fabric and withstand several washings,” Wilson said. “Aerosol cans of this product are available in the hunting and camping sections of some stores.”
Generally these products have a 0.5 percent permethrin concentration and have the words “For Clothing Only” displayed prominently on the label. Apply these products to outer clothing (shirt, pants, socks) only, at least two hours before use to allow adequate drying.
Permethrin must not be applied to directly to skin, Wilson stressed. Instead treat exposed skin as you normally would with an insect repellent, preferably containing DEET or picaridin.
“This combination is very effective in reducing mosquito bites and also works well in repelling ticks,” says Wilson. “One study found the mosquito biting rate was about one bite per hour when using permethrin-treated clothing and 35 percent DEET on the skin, compared to about 1,190 bites per hour for an untreated person.”
Clothing pre-treated with permethrin is also commercially available.
Always take precautions when working in heavily mosquito-infested areas. For more information on insect repellents, stop at your local South Dakota Extension office and pick up a copy of SDSU Extension Fact Sheet FS920, “Personal Mosquito Repellents.” Or download from the Internet at http://agbiopubs.sdstate.edu/articles/FS920.pdf.