Adulticide – Countywide – 6/15 – 6/19/2022

Posted on June 17, 2022

Notice of ground and aerial adulticide campaign with image showing a mosquito crossed out

UPDATE 6/17/2022 @ 12 pm: Aerial and ground treatments for Williston, Ray, Grenora, Epping, and Trenton were successfully completed last night as planned! However, due to forecasted winds and conditions for the weekend, it is unlikely Williston Vector Control will be able to conduct additional treatments through Sunday. Vector Control will continue to monitor trap counts and conditions to determine if additional treatments can be conducted. Stay tuned to this post or our Facebook page for updates!


UPDATE 6/16/2022 @ 2:45 pm: Weather and conditions permitting, the Williston Vector Control District will conduct the following adulticide treatments on the evening of Thursday, June 16th, beginning near sunset:

  • Epping
    • Ground
  • Grenora
    • Ground
  •  Ray
    • Ground
  •  Trenton
    • Aerial
  •  Williston
    • Aerial: Spray Blocks 1 – 12
    • Ground: Spray Blocks 13 & 14 and surrounding areas


The Williston Vector Control District is tentatively scheduled to conduct aerial and ground adulticide treatments for all spray blocks in the cities of Williston, Ray, Grenora, Epping, and Trenton from Wednesday, June 15 through Sunday, June 19. All treatments will take place near sunset, weather and conditions permitting. We will provide an operational update on the day of treatment.

For more information and a map of the WVCD Spray Blocks, please refer to the Spray Reports webpage.

Williston Vector Control uses Zenivex E20 for adult mosquito control treatments (adulticides), which contains the active ingredient Etofenprox. Zenivex E20 is a product approved for use in residential areas by the Environmental Protection Agency (EPA).

To avoid mosquito bites, citizens are advised to take extra precautions when spending time outdoors during the hours of dusk to dawn during the summer months. Wearing long sleeve tight knit shirts and long pants, limiting time outdoors during these times, and using a mosquito repellent such as DEET, Picardin, or oil of lemon eucalyptus are good actions to take to prevent bites. Citizens can help prevent mosquito re-population by eliminating standing water on their property.

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