Large flies nuisance in yard

Asked May 23, 2015, 9:53 PM EDT

I have for 2 years had a large number of flies, I think the black blow fly (?) in my patio area. I don't have much of a problem in the house.
I put up a bag fly trap it was very successful (gross) but didn't eliminate the problem.
I noticed the flies are coming out now if we have a break from the rain. I am in a residential neighborhood, no barnyards nearby...but my neighbor has a low spot on the property line that has standing water when they irrigate or it rains. Could that be a breeding ground? Thanks, C. Jones

Larimer County Colorado

1 Response

The most common large flies that show up in homes are the black blow fly (Phormia regina) and one or two species of bluebottle flies (Calliphora spp.). Both are reported to develop as carrion feeders.

Some other flies, such as the house fly (Musca domestica) will breed in decaying plant matter, and some flies develop on animal manure.

So, I do not think the low lying area is the breeding site for the flies if they are bluebottle or black blow flies. Possibly a wet spot could be a site for flies that breed in decomposing plant matter, but that doesn't seem to be the case.