If weather conditions are favorable for effective spraying, the City of Sioux Falls Health Department will be conducting ultra low-volume ground spraying efforts for mosquitoes in targeted areas of Sioux Falls this evening. A map on the City’s Website outlines the targeted zones where spraying will occur.

Sioux Falls Zones  1, 2, 3, 4, 5, 6, 7, and 8 are scheduled for spraying. This targeted spray effort is being conducted in response to increased numbers in Culex tarsalis (the encephalitis mosquito) and Aedes vexans (nuisance mosquito) populations. The Sioux Falls Phased-Response Guidelines indicate specific response parameters when numbers of Culex and Aedes species hit set threshold limits. Therefore, the Sioux Falls Mosquito Control Program is conducting comprehensive treatments including increased education, surveillance, and control measures in accordance with CDC and local phased-response guidelines.

This evening’s spray will begin at approximately 8 p.m. and will continue until approximately 1 a.m., or until the designated areas are completed. Once spraying commences, changing weather conditions may prevent the completion of some areas; any uncompleted zones will be revisited as soon as weather permits.

The City will be using Scourge (resmethrin) within the city limits. Scourge is a synthetic pyrethroid approved for use by the EPA in residential areas for adult mosquito control. Scourge is designed to break down in the environment quickly and at the very low concentrations used, is unlikely to cause adverse health effects in humans or mammals.

In order to be effective, all sprays for adult mosquitoes must be conducted in the evening or very early morning hours when the mosquito that transmits West Nile Virus is most active, and during favorable conditions of weather.

Although the exact dates for all future sprays are unknown, the Sioux Falls Vector Control Division is planning on conducting a citywide spray early next week. This spray is in response to the increase in numbers as well as the upcoming Fourth of July weekend. Further information regarding that spray event will be posted next week.

The Sioux Falls Mosquito Control Program is working hard to control mosquito populations, however it cannot prevent emergence on private property. Recent research from South Dakota State University has indicated that as much as 50 percent of Culex activity occurs in the two-hour period between 10 p.m. and 12 a.m. and peaked Aedes activity between 8 p.m. and 10 p.m. Such information guides our spray efforts as well as reinforces the need of individuals to use repellents throughout the evening hours when outdoors.

The following precautions should be followed to prevent mosquito bites and reduce the risk of West Nile Virus:

• Use mosquito repellents containing DEET, Picaridin, or Oil of Lemon Eucalyptus.
• Wear shoes, socks, long pants, and a long-sleeved shirt to limit exposure to mosquitoes.
• Limit time outdoors at dusk and dawn when mosquitoes are most active.
• Eliminate standing water that gives mosquitoes a place to breed.
• Support local mosquito control efforts.

The elderly, pregnant women, diabetics, transplant patients, individuals with high blood pressure, and those with a history of alcohol abuse should be especially mindful to take precautions. People with a severe or unusual headache should see their physician.

Residents are not required to relocate, stop activities, or take special precautions during mosquito control spraying. For safety reasons, residents should never deliberately approach or follow spray vehicles. People who want to avoid all exposure to the chemicals can take the precautions indicated on the City’s Website. An audible tone and visible signal will precede the marked spray truck. If residents have concerns or questions, they may check the City’s Website, cable channel CityLink 16, or call the Health Department for more information. Additional information on synthetic pyrethroids can be found at http://www.epa.gov/oppsrrd1/reevaluation/pyrethroids-pyrethrins.html.

Citizens do not need to call the Health Department to report areas of standing water a second time. All areas of town are being surveyed and previously treated areas will be rechecked. Citywide sprays cannot control private properties with large amounts of vegetation or standing water that harbor or support excessive numbers of mosquitoes locally; and therefore, these may require additional local control by the homeowner or business.

As progress is made toward completing the spraying process, updates will be placed on the City’s Website. In order to view the spray map or for additional information, visit the website at www.siouxfalls.org. Citizens wanting to report local concerns on biting or standing water should leave the required information on the automated Mosquito Reporting Hotline at 605 367 8799.