Bats - School IPM - USU Extension

    Lesser House Flies

    Fannia spp.

    lesser house fly

    Lesser house fly (Pest and Diseases Image Library, Bugwood.org)

    lesser house fly

    Lesser house fly (Brion Galiza, Wikimedia Commons)

    lesser house fly larvae

    Lesser house fly larvae (Pest and Diseases Image Library, Bugwood.org)

    Identification

    • similar in appearance to the house fly, but 2/3 the size (~3/16 inch)
    • 3 black stripes are visible on the back; the first two and a half abdominal segments are translucent yellow
    • larvae are whitish brown and covered in long protrusions on the back of the body

    Nesting Habits

    • breed in animal feces, decaying organic material and trash receptacles
    • males gather in large numbers and hover in areas with still air that are protected from sunlight

    Diet

    • larvae feed on animal feces and decaying organic material

    Significance

    • flies hover around structures in large numbers and can come indoors creating a nuisance
    • rarely land on food; not considered a disease vector

    IPM Recommendations

    • Locate breeding substrate and remove or alter.
    • Keep exterior doors closed, install screen doors, or install an automatic door closer.
    • Keep screens in good repair.
    • Improve sanitation around the structure, if possible.
    • Keep dumpsters and trash receptacles at least 50 feet from structures.
    • Keep trash receptacles and areas clean.
    • Close lids on trash receptacles.
    • Exclude fly entry via caulking, weather stripping, door sweeps, etc.
    • Properly place light traps to catch flies that come indoors.
    • Use a fly swatter.