Identify Your Pest Flying insects House fly
House fly
Musca domestica · Also called: Common house fly
The house fly is the grey, fast-flying fly most people find buzzing around kitchens, garbage cans and patio tables. It breeds in garbage, manure and rotting food, so many flies indoors usually point to a breeding spot nearby.
Size 6 to 7 mm long
Colour Dull grey with dark stripes and large reddish eyes
Key feature Four dark stripes running lengthwise on the back, just behind the head
Season Mainly late spring to early fall; fewer indoors in winter
Where Kitchens, garbage areas, patios, barns and doors near bins or compost
What it looks like
The house fly is a medium-sized grey fly about 6 to 7 mm long. Look at the section just behind the head, called the thorax. It has four dark stripes running from front to back. The eyes are large and reddish brown, and the fly has one pair of clear wings.
House flies cannot bite. They have soft, sponge-like mouthparts and feed on liquids. They land on food, garbage and pet waste, and often rest on walls, ceilings and light cords. Their young are small, pale, legless maggots that live in moist garbage, compost or manure.
Often confused with
Stable fly
Cluster fly
Little house fly
Signs to look for
Flies around bins or compost
Maggots in garbage
Small dark specks
Numbers that keep growing
Risks and damage
House flies do not bite or sting, but they are more than a nuisance. They feed and lay eggs on garbage, manure and rotting food, then land on counters and meals. Germs on their legs and mouthparts can be carried to food this way. Bacteria such as Salmonella and E. coli have been found on house flies. The risk matters most in food businesses and near animals. In a clean home, a few flies are mainly an annoyance.
In Alberta
House flies are found across Alberta, from Edmonton and Calgary to rural acreages. They are most active from late spring to early fall. Numbers are often higher near farms, stables, compost sites and waste bins. They slow down outdoors in the cold but can keep breeding in heated barns.
House flies taste with their feet. Tiny sensory hairs on their legs can detect sugar, so a fly knows a spill is food the moment it lands.
How to keep them out
Keep screens in good repair
Seal garbage and compost
Clean up pet waste
Cover food and wipe spills
When it is time to bring in a professional
Call a professional when flies keep coming back after you clean up, or you cannot find where they breed. The same goes if you run a restaurant, food plant or care facility. Technica’s licensed technicians can help find breeding sites, check entry points and suggest changes that lower fly numbers.
Frequently asked questions
Can house flies bite?
No. House flies have soft, sponge-like mouthparts and cannot bite. If a fly that looks like a house fly bites you, it is likely a stable fly. Stable flies have a pointed mouthpart and are common near horses and cattle.
How long does a house fly live?
Adults usually live about two to four weeks. In warm weather, a house fly can go from egg to adult in as little as 7 to 10 days. That is why numbers can climb quickly in summer.
Why do I have flies inside when my home is clean?
Flies often come in through open doors or torn screens. They may also be breeding somewhere hidden, such as a forgotten bag of garbage, a compost pail or spilled food under an appliance. Many flies at once is worth looking into.