Manage account
For your home
© 2025 Rentokil Initial plc and subject to the conditions in the legal statement.
Fly Control for Commercial Premises
As the seasons change and temperatures drop, autumn flies (Musca autumnalis) become a common nuisance for homeowners and businesses alike. These pests are often mistaken for house flies or lesser house flies and are particularly active in the fall, when they can gather in large numbers.
What are autumn flies?
Autumn flies—also known as face flies—are a species of fly commonly found in rural and suburban areas. They are closely related to house flies. These pests primarily target livestock and horses but can become a problem for homeowners, especially in cooler months when they seek shelter indoors.
Key characteristics
- Similar in appearance to house flies, autumn flies are slightly larger. Females are almost identical to the house fly, but males have an orange abdomen with a black mark down the center. The female is approximately one-fourth of an inch long, and is generally larger than the male.
- Females are known for feeding on animal secretions, which can make them a nuisance around farms and stables. Flies affect both horses and cattle and are usually seen on the face, often around the eyes.
- These flies usually cluster on warm surfaces, especially in the fall when temperatures drop.
- Unlike horse flies, they do not bite but can still spread bacteria and pathogens.
- At night they rest on vegetation or man-made structures. Most daylight hours are spent feeding on plant sugars, the surface of manure deposits, or animals.
- On host animals, they obtain protein from nasal mucus, saliva, and tears. The flies have microscopic “teeth” on their mouthparts, which are used to stimulate the flow of tears and aid this feeding process.
- They are strong fliers and are capable of traveling several miles, but most stay within the vicinity of their breeding grounds.
The life cycle of autumn flies
- Breed in animal dung in fields.
- Undergo a complete metamorphosis with distinct egg, larva or maggot, pupal, and adult stages.
- The white eggs, about 1/32" in length, are laid singly but pile up in small masses. Each female fly can lay up to 500 eggs in several batches over a three to four day period.
- The life cycle can be complete within 12–20 days, depending on temperature, with as many as 12 occurring in one summer.
Seasonal behaviors of autumn flies
In the warmer months, autumn flies lay their eggs in fresh manure, where the larvae develop. As fall approaches, adult flies seek shelter in buildings, barns, and attics to escape the cooling temperature. This is when infestations become most noticeable, as large swarms can gather on sunny walls and windows.
Habitat and diet of autumn flies
As fall arrives, these flies seek out environments that provide both warmth and a reliable food source.
Preferred environments
Autumn flies thrive in areas with livestock, particularly farms and stables, where they have access to manure for egg-laying. However, they also invade residential properties, seeking warmth and shelter as the weather cools. Unlike the drain fly, which prefers damp, organic matter, autumn flies are more likely to be found in open, sunlit areas.
What do autumn flies eat?
Adult autumn flies mainly eat organic matter and liquids, including animal secretions, nectar, and sugary foods. Females are particularly drawn to livestock, where they consume eye and nasal fluids. This behavior can cause irritation to animals and make the flies a significant pest in agricultural settings.
Managing autumn flies
Managing autumn flies needs both prevention strategies and effective control measures.
Preventing autumn fly infestations
Preventing autumn fly infestations starts with proactive measures.
- Seal entry points around doors, windows, and vents to stop flies from entering buildings.
- Install fine mesh screens on windows and doors to further block access.
- Keep your environment clean by regularly disposing of waste and cleaning up food sources.
- Good manure management on farms helps reduce breeding spots. Keeping animal areas clean and dry also reduces conditions that attract pests.
Effective autumn fly control methods
If an infestation occurs, a combination of these methods can help eliminate autumn flies.
Insect light traps effectively reduce fly populations indoors. Outdoor fly traps can be placed around farms and stables to catch flies before they enter buildings. Professional insecticides and residual sprays provide long-lasting control when used on entry points and areas where flies gather. Integrated pest management (IPM) strategies, including biological controls, can also help lower fly numbers in agricultural settings.
Contact us today for a free quote and more information about our fly control services.
Frequently asked questions
How do you identify an autumn fly?
They are slightly larger than house flies, with a dull gray or brownish body and an orange abdomen. Males have a yellowish tint and can be confused with the cluster fly. Females, on the other hand, are known for feeding on animal secretions.
Why are autumn flies called face flies?
Autumn flies are often referred to as face flies because they frequently land on the faces of livestock to feed on eye and nasal fluids. This behavior can irritate animals and contribute to the spread of bacteria.
How long do face flies live?
The lifespan of face flies varies based on environmental conditions. On average, they live for about two to three weeks, though they may survive longer in sheltered indoor environments during colder months.
How big are autumn flies?
Autumn flies are slightly larger than house flies, typically measuring between six and seven mm in length. While not as large as horse flies, they are still easily recognizable by their size and behavior.