Why Flies Are Invading Your Home During The Winter And How To Stop Them

If you have issues with flies around your property, you may look forward to the cold temperatures of winter to eliminate these nasty little insects. However, not all flies disappear in winter, and seeing them inside your home during the cold months takes the cringe factor to a new level. You may wonder how it's possible that you have these insects in your home while also looking for ways to naturally keep flies out of your house.

It's important to understand that seeing these insects in your home in winter doesn't necessarily mean that you have poor hygiene or gross conditions inside your house. The insects are either in your home in search of shelter, moisture, and nutrition, or you've brought them in inadvertently. The cluster fly and the fruit fly are the most common species to see indoors during winter. Adult cluster flies don't feed on rotting food or decaying flesh like other types of flies. They are seeking water and nectar, and they might move indoors in winter to escape cold temperatures and maintain access to liquids. Meanwhile, fruit flies may enter your home at any time of the year. They might end up in your home because they laid eggs on a piece of fruit that you bought at the grocery store. Once those eggs hatch, you have an indoor infestation that seems to come out of nowhere. The best way to get rid of the flies depends on what type of insect has invaded your home. 

Cluster flies look similar to common house flies, but they're larger. They have a dark gray body color and multiple gold-colored hairs on the thorax, which other common fly species lack. These flies tend to move slowly, since they're usually semi-dormant during winter. Cluster flies primarily live outdoors from spring through autumn. However, as the amount of daylight begins to decrease heading into winter, these insects change their habits, looking for sheltered indoor areas where they can survive through the winter. If you have cracks and gaps around windows and doors, these insects will move into your home before winter hits.

Cluster flies frequently remain in a dormant state throughout winter, even after penetrating your house. However, if you have some warm, sunny days in winter, they may start to become active. The good news is that if you start seeing cluster flies sluggishly moving around your home, they don't pose the same risk of contaminating food and spreading disease as houseflies and other insects. They don't spend time feeding on garbage or rotting carcasses like some other insects, so they don't carry similar bacteria.

However, you'll still probably want to eliminate cluster flies as quickly as possible. You can spray them with an indoor-approved pesticide to kill them whenever you see them. Because they move so slowly, you often can vacuum or swat these insects. To prevent them from coming into the home in the first place, seal gaps and cracks before autumn arrives.

Adult fruit flies are extremely small, usually measuring about 1/8 of an inch in length with a tan color on the body and noticeably red eyes. These tiny insects rarely live more than 30 days, but they reproduce rapidly, meaning you can see an infestation in very little time.

Some people might compare them to gnats because they both present more of a nuisance than a threat to humans. Although they're both small, some differences exist between fruit flies and gnats. First, fruit flies do not bite or sting humans, whereas some types of gnats do. Another key difference is that fruit flies can cause food to rot. Produce attracts fruit flies, and the droppings they leave behind contain an enzyme that spoils the food. They also lay eggs on fruit and vegetables on the countertop. 

Keeping fruit flies away entails storing all your produce inside a refrigerator. You can wash produce when you purchase it, but some eggs may remain behind. If you are seeing active fruit flies, you'll need to trap them. Mix apple cider vinegar with a little dish soap in a bowl to lure them into the mixture — they'll get stuck and drown there. You can also buy traps, like these Terro Fruit Fly Traps, that work in a similar way and last about 90 days.