top of page
Image of a Wyoming prairie _edited.jpg

Filth Flies

Filth Flies


Filth flies (House Flies) are common flies that are most common around animal waste, food waste, and garbage. Large numbers of filth flies are a natural result of the many livestock, people, and food vendors that arrive at Frontier Park every year for Cheyenne Frontier Days. The City of Cheyenne Weed and Pest coordinates with Laramie County Environmental Health Department to reduce fly pests and minimize the risk of disease transmission from filth flies and to improve the quality of life for all humans and animals at the park.

Biological Control of Filth Flies

Two different biological management methods are used on the park grounds during Cheyenne Frontier Days. As a first line defense, roundworms are applied to livestock areas weeks before animals arrive. These roundworms infect developing flies and stay in the area continuing to reduce flies. These worms do not harm non-insects and are a safe and organic method to limit the number of flies during the event.

While roundworms are an effect means to fly management, multiple control methods are more effective than a single treatment. In addition to roundworms, small parasitic wasps are spread around animal pens weekly after livestock arrive on the grounds. Immature wasps eat immature flies, and as the wasps grow in number this effect increases. These wasps are about the size of a gnat and do not bite or sting humans and animals.  


Mechanical Management

Over 100 disposable fly traps are place around Frontier Park during July and August to help contain filth flies.  Traps help our biological management efforts and keep flies from moving outside the park or from reaching food vendors on the west end of the grounds. Additionally, we monitor fly populations during Cheyenne Frontier Days to make sure our treatments are effective and flies are not moving to the populated areas near Frontier Park.

bottom of page