Horn Flies

• Identification:

  • Congregate along the back and sides of cattle
  • Small (3-5mm)
  • Bloodfeeders

• Prevention and Control:

  • Ear-tags should be used once 100-200 flies per cow are present to help avoid resistance and should be removed in the fall
  • Pour-ons such as ivermectin can be used but are only effective about 28 days so reapplication is necessary
  • Back rubbers and dust bags can be effective when hung in locations cattle can self treat and don’t require handling of cattle
  • Oral larvicides can be beneficial mixed in feed or mineral but only protect against more larvae, not from adult flies

Face Flies

• Identification:

  • Dark gray in color
  • 6-8 mm in size
  • Non-biting, but contribute to pink eye
  • Congregate around wounds as well as ocular and nasal discharge

• Prevention and Control:

  • Pyrethroid ear tags
  • Pour-ons
  • Back rubbers and dust bags can be effective when hung in locations cattle can self treat and don’t require handling of cattle
  • Control can be more difficult as these flies spend fewer moments on the cattle

Stable Flies

• Identification:

  • Gray with checkerboard pattern
  • 7-8 mm in size
  • Bloodfeeders
  • Congregate on legs
  • Present mid-May through September

• Prevention and Control:

  • Sanitation is most effective, removing locations for larvae to develop such as manure piles
  • Measures should be taken when even 5 flies per head are present
  • Tend to rest in shaded areas and premise spraying can create some relief