Flies are a common pest around the world – with more than 120,000 kinds of flies found globally, and 18,000 of those found throughout North America. Although flies have short lifespans, they are able to quickly reproduce in large numbers and are also capable of spreading various dangerous diseases, including malaria, salmonella and tuberculosis.
Flies typically hatch outside and then make their way into our homes through structural weak spots, such as damaged weather stripping or torn screens covering windows and doors. Around the home, flies can lay their eggs in garbage cans, compost piles, excrement, and rotting organic material. Female flies can lay between 75 to 150 eggs at a time, which if compressed together only adds up to roughly the size of a pea, making them extremely difficult to identify.
Fruit flies, another common fly type, are usually found within the home because of their attraction to food waste like overripe or rotten produce. They typically enter the house as hitchhikers on produce and other food brought in from the outside. Horse flies are not commonly found inside and do not feed indoors, but sometimes enter homes by accident through open windows and doors.
The large sluggish flies known as cluster or “attic” flies (Pollenia rudis and relatives) often invade homes in fall and turn into wintertime pests. They are particularly noticeable on warm winter days when they become active and find their way into living quarters. Just when you think you have them under control, more appear the next day, creating the impression they are breeding inside the house. In reality, they are only using your home as a place to spend winter and do not cause damage to the buildings, furniture, or occupants.
The best line of defense against cluster flies is to prevent their entrance into buildings. Where possible, seal up cracks in the siding and around windows with caulking and cover attic vents with wire screening before the Fall starts. Cluster flies are usually sluggish and make little attempt to escape, so they can easily be picked up with a vacuum cleaner or swatted with a fly swatter. If you use a vacuum cleaner to clear up sluggish flies, remove the bag and place it outdoors, or the flies inside may crawl back out.
Fruit flies are found throughout the United States and are known for their ability to rapidly reproduce. They can be found indoors year-round, and depending on the conditions, their lifespans can last 25 to 30 days. Adult fruit flies are typically 3 to 4 mm long and appear to be brown or tan in color. They usually have red eyes, but some fruit flies have darker eyes. They have a tan thorax with a black and grey abdomen. Fruit flies have six legs and are small and oval in shape with antennae.
Fruit flies are attracted to and eat rotting food matter, especially fruits and vegetables, and any fermenting liquids, like beer, liquor and wine. They are also attracted to and sometimes breed in dark, moist and unsanitary environments like drains, garbage disposals and trash bins. Fruit flies are able to reproduce very quickly, making them difficult to control. Female fruit flies can lay around 500 eggs, which can hatch in as little as 24 hours. Similar to other fly species, fruit flies have a four-stage lifecycle, which can be completed in as little as a week in ideal conditions.
Not only are fruit flies a nuisance pest, but they are also capable of contaminating food with harmful bacteria and disease-causing pathogens, since they are typically found in unsanitary conditions, just like house flies.