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Pesticide Applications

The City of Cheyenne Weed and Pest applies insecticides and herbicides only when necessary, to protect the integrity and resilience of our urban ecosystem, and our communities health.

ULV truck spraying applications for adult mosquitoes will typically be posted by 4:00pm the day that spraying will occur. We do not start until after sunset.

There are currently no scheduled operations. 

Herbicide applications for noxious and invasive plants will be posted the day before with estimated times, products to be used, and locations.

There are currently no scheduled operations. 

ULV Truck Spraying Applications

When West Nile Virus positive rates and/or mosquito populations are intensely high, we will treat problematic areas with truck mounted equipment at night to reduce adult mosquitoes populations.

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This process is called ULV (ultra-low volume) spraying, where a very minimal amount of insecticide (think 2oz) will be misted in tiny droplets over a large area (think a football field). Those droplets will float and hang in the air, waiting for a tiny mosquito to fly through them. This process and the products we use are certified by the EPA and backed with scientific research. We spray only when mosquitoes are active, and very few other insects are. 

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All applications are on a weather permitting basis. Winds in excess of 8-10mph or temperatures below 60F will halt operations. Crews will attempt to resume operations the following evening.​

More information on ULV truck spraying is available from the CDC HERE.

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Spraying trucks will be going at slow speeds and have strobe lights on. To maintain the safety of employees and residents, trucks will not stop to answer questions. If you have questions or concerns about Weed and Pest ULV applications please contact us at 307-637-6475 or email us at weedandpest@cheyennecity.org

Larval Mosquito Treatments

The Weed and Pest monitors over 700 sites around Cheyenne that produce and have the potential to produce mosquitoes. We primarily use a bacteria product (Bacillus thuringiensis) that is naturally found in the soil, to control the larval-stage mosquitoes when they ingest it. This is quick-acting but not persistent, so we apply it frequently. BTI does not harm fish or other aquatic life because they do not have the receptors to be harmed. 

We also use a longer-lasting growth regulator (methoprene) product that disrupts the life cycle of the mosquito, so it fails to emerge as an adult.

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We are applying these products throughout the mosquito season, usually from April to October. You will see employees in high-visibility vests applying these products from motorized backpacks into stagnant ponds, ditches, creeks, and culverts around town. â€‹

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Herbicide Applications

Herbicides will be applied when necessary to control designated noxious weeds on City owned property. Times, locations, and product used will be listed here on the day before the applications. All applications are on a weather permitting basis.  

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The Weed and Pest monitors invasive and noxious weeds around town, and will treat only city-owned property when necessary. The county and state maintains an invasive plant list, that threaten native vegetation. We also use mechanical and biological methods to control the weeds. 

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​​To see products used to treat noxious and invasive weeds click HERE

To learn more about our integrated invasive weed management click HERE.

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