If you have ever had one of these big blow flies in the house (they are almost ½ inch long), you know how much of a nuisance they can be. Their loud buzzing flight is quite annoying, and they are pretty good at evading the fly swatter. They usually fly for some time before landing, and when they do land, it is often in some out of the way place where you can’t see them until they fly again. Because they are attracted to lights, they will follow you from room to room as you turn out the lights to go to bed. They won’t tuck you in, but they will hum to you as you try to read before turning out the bedside light.
Indoor infestations of blue bottle flies can occur simply because one followed someone though the door, but infestations can also result from flies that developed inside the house on some suitable breeding substrate. These are blow flies, which means they breed in feces or decaying meat, things like pet feces, mouse or rat carcasses, “lost” bowls of canned pet food, and similar items. This particular species can also be important in forensic entomology, but enough said about that.
Control: Good insect exclusion is the best defense against these and other home-invading insects. Fly swatters are effective remedial control for small infestations. But any time you see blue bottle flies indoors, especially if there’s more than one, it’s a good idea to search for possible breeding sources. Often, by the time adult flies have emerged inside the house, the breeding source in which the maggots developed has already dried up to the point that it will not support another generation, but you will still want to find it and get rid of it if you can.
Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service.
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