If there are large metallic-colored flies buzzing around your home or yard, you probably have blow flies.
Blow flies have shiny blue, green, bronze, or black bodies and make a loud buzz when they fly. Blow flies are bigger than house flies, and they’re usually the first things to arrive when something dies. Blow flies eat dead animals, rotting organic material, and animal feces.
In this article you’ll find out:
- How to identify blow flies
- Types of blow flies
- Why you have blow flies in your house
- Are blow flies harmful?
- How long a blow fly infestation lasts
- How to get rid of blow flies
How to identify blow flies
The following table gives a list of characteristics on what to look for to identify a blow fly:
| Known as | – Blow fly or blowfly – Bottle fly |
| Color | Metallic green, blue, bronze, or black body |
| Average length | 0.3 – 0.4 inches (8 – 10 mm) |
| Description | – Slightly bigger than the common house fly – Bristle-like hairs on the back – 6 legs – 2 transparent wings |
| Flight patterns | Make a loud buzzing sound when flying |
| Attracted to / Where to find blow flies | Look for blow flies: – Near garbage, especially if there are meat scraps – Near newly dead animals, such as a squirrel that has died in a wall, attic, or crawl space – By broken sewer pipes – In cat litter trays and animal feces |
| Eggs | Females lay 200 – 300 eggs at a time: – On a dead animal – In the wound of a living animal – In animal feces – In garbage – In rotting grass clippings – In neglected compost piles – In the eyes, nose, or ears of a healthy animal |
| Breed | – Usually breed outdoors – Pale yellow or white worm-like maggots hatch from the eggs and eat whatever they were laid in |
| Eat | – Dead animal carcasses – Animal manure or feces – Rotting organic material – Garbage |
| Most active | During the day |
Types of blow flies
There are about 80 types of flies in North America and 1 200 in the world that are considered to be blow flies. Some common types of blow flies are carrion flies, greenbottle flies, bluebottle flies, cluster flies, and screwworms.
Why you have blow flies in your house
At first, blow flies might be attracted to food or a suitable breeding area near your house or in your yard. But blow flies can smell food up to 1 mile away, and if they smell food in your house they will come in through an open door, window, or any cracks and small openings to look for the food.
Blow flies are most attracted to garbage, animal feces (such as a dirty cat litter box), spoiled meats, and animals with open wounds.
Click here for a list of all the ways flies might be getting into your house.
Are blow flies harmful?
Blow flies cannot bite or sting, but they spread germs when they land on feces or rotting matter and then move on to surfaces in our homes. Blow flies can harm animals by laying eggs in their wounds, eyes, noses, and ears. Maggots hatch from the eggs and eat the animal’s flesh.
How long a blow fly infestation lasts
A blow fly infestation lasts as long as blow flies have food to eat and a suitable place to lay their eggs. Once the food source and/or breeding ground has been removed, blow flies soon move on or die off.
Most adult blow flies live for two weeks to one month.
Blow flies might spend winters in your house if they find somewhere suitable to hide on cold days, but you should still see them come out and be active on warm days.
Click here to find out what flies do in winter.
How to get rid of blow flies
Below is a list of recommended methods and products from Amazon that you can use to kill blow flies and stop them from coming into your house:
Remove food and breeding areas: Remove any rotting food scraps, garbage, animal feces, carcasses, and grass clippings from your yard or home. Don’t leave dirty dishes in your kitchen sink, and keep garbage bins sealed tightly.
If blow flies keep getting into your bins, stick a garbage guard under the lid. This little device kills flies, maggots and other insects in bins for up to 4 months.
Stop blow flies from getting inside: Seal any cracks or openings in your roof or walls, and repair fly screens on the door and windows. If you like leaving your doors and windows open, and you don’t have any fly screens, hang one of these magnetic screen doors or magnetic screen windows to stop flies from coming in.
You can also leave a fan blowing against open windows and doors to stop blow flies from getting in.
Catch blow flies in a sticky trap: Blow flies are attracted to natural light by windows and doors during the day. Try hanging sticky fly ribbons or stick these window fly traps to any windows where you see blow flies. These sticky options are a safe, non-toxic way to quickly and easily catch blow flies.
If you have a serious fly infestation and need a tougher solution, try hanging a few TrapStiks. These are perfectly safe for indoor use and have no odor or chemicals.
Use a fly swatter to zap blow flies: Sprays and insecticides are not a good option for killing blow flies – the sprays spread poison around your home and the flies breed so quickly that they often become immune to products you use regularly. Instead, keep one of these electric fly swatters nearby to kill blow flies that fly past you.
Hang a fly trap outside: Hang these fly traps outside, at least 20 feet from your doors and windows. They attract all kinds of flies, including blow flies, and drown them. The traps are disposable – just seal them in a plastic bag and throw them out.
