House Flies

We’re guessing you’re pretty familiar with house flies. While these flies are mainly a nuisance pest, they’re known as “filth flies” for a reason. They’re capable of being ‘mechanical vectors’, meaning they can transfer human pathogens from one location to another. Plus, they tend to feed on not-so-appetizing things like decaying garbage and pet waste. At Sunday, we’ll help you keep these insects away from your next BBQ and hopefully, out of your home too.

Why is a House Fly a Pest?

Beyond flying around you and crawling on your food, a house fly is a pest for two major reasons: 

  1. House fly larvae develop and pupate in rotting materials, including carcasses, feces, garbage and decaying plant materials. Adult flies emerge from these sources.
  2. They’re suspected of transmitting at least 65 diseases to humans including typhoid fever, dysentery, cholera, poliomyelitis, yaws, anthrax, tularemia, leprosy, and tuberculosis.
  3. They regurgitate and excrete wherever they come to rest (your lunch, for example), mechanically transmitting disease organisms.

How to ID house flies

Getting familiar with house flies and being able to properly ID them is the first step to Sunday’s integrated pest management approach. They have two very similar lookalikes, so take notice of their habitat preferences, physical characteristics, and behavior to know whether you are dealing with a house fly or a close relative.

Quick Adult House Fly ID

  1. Dull gray, may have some yellowish coloring
  2. One pair of wings
  3. ⅛ to ¼ inch
  4. Four dark stripes on thorax
  5. Unpatterned abdomen
  6. Sponging mouthparts for feeding on liquids
  7. Non-biting


Quick Larva (maggot) ID Info

  1. Pale or cream colored
  2. Length of ⅛” to ⅓”
  3. Legless, squirmy
  4. Black mouth hook is visible at the tapered end (head)


P.S. Unsure if what you’re looking at is really a housefly? Here are some common lookalikes:


Stable flies

  1. Similar in size and color
  2. Seven circular spots in a checkerboard pattern on their abdomens
  3. Long, bayonet-like mouthparts for piercing skin and feeding on blood
  4. Obligate blood-feeders, meaning they will bite humans or pets if cattle and horses aren’t available

Flesh flies

  1. Large and gray with distinct hairs and a checkerboard pattern on the abdomen
  2. Three dark stripes on top of thorax
  3. Slow and loud when flying

Cluster flies

  1. Similar dull gray coloring with yellow hairs on the abdomen
  2. Overwinters inside structures, attics and walls
  3. Mainly seen indoors January-March

When are House Flies Active?

House flies are most active and abundant in the summer months. Larvae are called maggots and they develop in decaying organic matter. 

Sunday Funday Fact: House flies only live for a short time – and it all depends on temperature. At 60°F, a house fly goes through its life cycle in 45 days, but at 95°F the life cycle is shortened to just 7 days.

Where Do House Flies Live?

These flying insects are the most common fly species in and around structures and are found in every region in the US (actually found worldwide!). They’re fully capable of living both indoors and outdoors too. And while they can travel long distances, house flies prefer to stay within 2 miles of their larval food site. 

Natural Pest Prevention and Reduction Practices

If at all possible, we recommend incorporating Integrated Pest Management practices prior to reaching for chemicals. Here are a few methods to help you deal with house flies this summer:

Sanitize and clean. Keep trash can/garbage lids closed and secure and remove trash regularly (especially during summer).

Remove food sources. Reduce breeding opportunities by removing food sources, including manure, garbage, grass clippings, weed piles, or other decaying organic matter where maggots develop.

Seal entryways. Properly seal window and door screens, and caulk or plug any openings or cracks into the home.

Trap and remove. Incorporate light traps, sticky traps (fly paper), container fly traps and fly swatters before reaching for chemicals.  


Sunday ProTip: Reduce house fly presence by reducing or removing potential outdoor breeding sites. Remove moist decaying plant material and animal waste from your yard, plus cover and aerate your compost piles regularly.

The Sunday Way to a House Fly-Free Home + Yard

Sunday’s Bug Doom is a biodegradable, canola oil and pyrethrin-based yard and home pest control spray to kill and repel house flies (among other pests) on contact and for sustained periods of time.

Here’s how to use it: 

  1. As with all pesticides, always read the label first and wear required eye protection and full-length clothing when applying.
  2. Spray directly onto house flies or as a perimeter treatment as instructed, thoroughly covering infested areas and places house flies frequently are found.
  3. Repeat as necessary. 

Sunday Application Tips: 

  1. Bug Doom is available as a barrier treatment to keep insects out of homes, around perimeters of flower beds, and other protected areas, as well as a ready-to-use spray. Make sure to use the right one in the right place! 
  2. Avoid spraying consumable vegetables, flowers, succulents, and pollinator-friendly or flowering plants.

Cited Sources

Entomology and Nematology. house fly – Musca domestica. University of Florida.  

Hahn, J. and V. Cervenka. Flies. University of Minnesota Extension. 

Jacobs, S. House Flies. PennState University Extension. 

Kaufman, P.E. and E.N.I. Weeks. Stable Fly. University of Florida. 

Utah State University. Flesh Flies