The Stable Fly (Stomoxys calcitrans) is gray with dark abdominal spots; forward-pointing proboscis and typically measures ¼–⅜ inch. The stable fly (Stomoxys calcitrans) closely resembles the house fly but is distinguished by its forward-projecting, bayonet-like proboscis used to pierce skin and feed on blood. Both males and female.

The Stable Fly poses a moderate risk. Painful bites to humans and animals. Significant livestock pest — causes economic losses through stress and reduced productivity. Can transmit some animal diseases.

In Arizona, stable flys are most often encountered in the following situations: Painful bites on lower legs, ankles, and feet. Flies with a forward-pointing proboscis visible at rest. Livestock bunching together, stomping, and showing behavioral signs of irritation. Breeding in wet hay or manure piles.

The Stable Fly is most active during: Year-round in Arizona; peak spring through fall. Arizona's warm desert climate can extend activity periods compared to other states, so year-round vigilance is recommended in the Phoenix metro and surrounding areas.

Remove and compost wet hay, manure, and decaying vegetation promptly. Keep livestock areas clean and dry. Use fly repellents on livestock. Screen barn openings.

Source reduction is essential — eliminate breeding sites. Residual insecticide treatments in livestock facilities. Fly traps and sticky tapes. Repellent applications for livestock and humans in affected areas.

Most fly species are drawn to food sources, moisture, organic waste, and breeding sites. For Stable Flys specifically: Painful bites on lower legs, ankles, and feet. Flies with a forward-pointing proboscis visible at rest. Livestock bunching together, stomping, and showing behavioral signs of irritation. Breeding in w. Eliminating attractants is the first step — Pest Control Bros can identify the source and recommend targeted control.