What are the large gray flies flying into the house?
What are the large gray flies flying into the house?
If a relatively large gray fly flies into the house, noticeably larger than a common house fly, grayish-black in color, sometimes with several dark longitudinal stripes on the back, it is likely a latrine fly (also called a stable fly).
Differences between latrine flies and house flies
- Size: latrine flies are 30%-50% larger and more robust than house flies.
- Color: latrine flies are grayish-black with dark stripes on the back; house flies are grayish-brown without obvious stripes.
- Activity: latrine flies fly more steadily, not as agile as house flies.
- Preference: latrine flies prefer decaying organic matter and feces; house flies prefer food scraps and kitchen waste.
Why do latrine flies fly into the house?
Latrine flies appearing indoors usually indicate problems in the surrounding environment:
- Nearby garbage accumulation.
- Garbage bins not emptied for a long time.
- Animal feces or rotting plant piles in the yard.
- Unhygienic areas in the hallway or neighborhood.
Latrine flies entering the house are usually incidental; they do not actively seek food like house flies. But frequent appearance indicates the surrounding environment needs attention.
Treatment methods
- Check and remove nearby sources of decaying organic matter.
- Seal garbage bags; cover garbage bins.
- Install screens to prevent entry.
- Spray dinotefuran-containing household insecticide on window sills and doorways to form a protective layer.