Flies come in many varieties, like all pests and insects, but the most common is the house fly. Generally black (some times with a green abdominal sheen) with red eyes, these two winged insects swarm and infest near and around easy accessible foods sources. Food sources are trash or rooting food, as well as waste. That's why another name for these pests are filth flies.
Flies pose a health risk to humans, pets and livestock and can infest your home or business and spread diseases like Salmonella and E. coli. A few fly species may even bite humans and animals.
If a small fly problem is left uncontrolled, it has the potential to turn into a serious infestation. Some fly species are able to mature from eggs to adults in just seven days.
SIGNS OF INFESTATION
As in most cases with pests, an infestation can be identified when the population of the pest explodes and they swarm, making their identification hard to ignore. Flies also have the added negative impact of their larvae (none commonly as maggots) which can also swarm. You can generally see maggots around the food source (where the flies lay their eggs). Removing the food source (or at least removing it from the proximity of your property) is the first step in trying to control the fly infestation.