Fed Up With Flies
August 16, 2009
About a week ago, we found maggots inside one of our outside trash cans. We disposed of the trash can and thoroughly cleaned the area around it as well. We are extremely clean people, so we never have food trash laying around the house, or feces, or any type of decaying matter. This is the first time we have had a problem with flies. A few days after this happened, we starting noticing swarms of flies in our basement. We have a finished basement and it is kept as clean as the rest of the house, so this was strange. Anyway, we killed all of the ones we could find with a handy dandy vacuum and newspaper. It seemed to have been over, but a few hours ago we had another bout of them, upwards of 30 or so. I did a bit of my own research online and identified them as blow flies. They are a green, blue metallic color. I also found that these flies have to lay eggs in rotting animals or organic decaying matter. We have looked EVERYWHERE in the house and around the house for possible ‘n esting sites’ yet to no avail. I am wondering where they could have come from the second time? Seeing as though there are no decaying animals or trash cans to lay eggs in, why are we getting a second round of these little guys? What can we do to make sure there’s not a round three?
St. Louis, Missouri
We believe your Blow Fly is a Common Green Bottle Fly, Lucilia sericata. We have gotten similar accounts in the past and the seemingly magical appearance of flies in ancient times fostered the belief in Spontaneous Generation. It is possible that there is a dead animal somewhere within your walls that is causing the flies to appear. It should also be noted that the maggots crawl away from the food source to pupate. The maggots might have migrated before you located the problem, and even if the source of the infestation has been located, the pupae are most likely in a different location. Once metamorphosis occurs, the flies seem to magically appear. We expect that you are probably at the end of this annoying household intrusion.