Horse and Deer Flies
Tabanidae
Identification
Horse flies
- large; brown or black in color
- large colorful eyes
- biting; sword-like piercing/sucking mouthparts
Deer flies
- generally smaller than horse flies
- yellowish brown to brownish black in color
- dark markings on wings
- biting; sword-like piercing/sucking mouthparts
Nesting Habits
- develop in moist or aquatic areas like moist soil, ponds, lakes and marshes
Diet
- females: animal blood
- males: flower nectar
Significance
- can travel up to a mile from breeding sites
- inflict painful bites that can result in visible, bleeding wounds
- transmission of tularemia and anthrax possible, but very rare
- rarely a significant problem inside structures
- can be a severe outdoor problem in areas near wetland habitats
IPM Recommendations
- If large numbers of deer or horse flies are present, inspect the area for possible breeding sites. (Breeding sites may be located off property.)
- Install properly fitting screens in windows.
- Use insect light traps to catch flies inside.
- Fly traps can reduce populations outdoors.
- Keep doors and windows closed, or open with properly fitted screens.