Use mosquito repellents outdoors South Dakota's first reported cases of West Nile Virus in humans this year underscore the importance of using mosquito repellents on Fourth of July outings and other outdoor events.
South Dakota State University Extension Pesticide Education Coordinator Jim Wilson said personal repellents offer the best protection against mosquitoes that can transmit West Nile Virus.
Scientific tests show repellents containing DEET or Picaridin applied to skin and clothing offer protection for the longest duration, Wilson said.
DEET-free alternatives with ingredients such as oil of lemon eucalyptus offer protection for shorter lengths of time are also available. For severe mosquito conditions, individuals can use special
formulations of an insecticide containing permethrin that may be applied only to clothing to supplement the DEET or Picaridin on exposed skin.
Individuals can also protect themselves by wearing
loose-fitting, long-sleeved clothing and by not being outdoors when mosquitoes are most active near dusk and dawn, Wilson said.
Wilson added that when planning an outdoor event, homeowners can use portable thermal foggers that use either propane or electricity to convert an insecticide (resmethrin) and fuel oil into a thermal or "hot" fog. Thermal foggers only kill mosquitoes that come in contact with the insecticidal fog, which usually dissipates within hours after fogging.
It's important to be sure that individuals do not object to the smoke, Wilson said.
Homeowners can also consider longer-lasting barrier or residual treatments of mosquito resting areas when outdoor gatherings are planned. Apply a labeled insecticide onto mosquito resting areas around the yard and home with an ordinary household sprayer, hose-end sprayer, or ready-to-use container equipped with a spray gun.
Apply the insecticide to surfaces where mosquitoes will be resting during the day such as the north or sheltered sides of board fences, wall siding, eaves, and outbuildings; trees and shrubs; under decks; and in tall grass or weeds.
Apply in advance of the planned activity so that the treated surfaces are completely dry before use. For more information refer to SDSU Extension Fact Sheet 923, "Controlling Mosquitoes around the Home and Yard," and SDSU Extension Fact Sheet 920, "Personal Mosquito Repellents."
The publications are available at local Extension offices or online at http://sdces.sdstate.edu/westnile/publications.htm.