Jul 5, 2012 – Phorids In Mortuaries

QUESTION:

What is the best treatment for reducing gnats and phorid flies in a funeral home/mausoleum?

ANSWER:

Small flies can be really frustrating because of the varied places they may be coming from. I will assume that by "gnats" you may be referring to fungus gnats, since these are fairly common small flies in this kind of situation too, and both fungus gnats and phorids could have a common source or they may be from entirely separate ones. Fungus gnats will be associated with moist settings because of the tiny bits of fungus and molds that may grow in that situation. Phorid flies are usually associated more with something wet and high in organic matter. Occasionally this turns out to be wet soil under a slab where plumbing has ruptured and released sewage into that soil, and of course this is a serious problem that is going to require a plumber and a lot of work to repair. 

However, phorids also breed in more local settings such as drains, places where water has settled and remained, places where garbage may be forgotten and rotting such as improperly cleaned waste receptacles, under refrigerators, in catch pans under potted plants, etc. In a restaurant it might be in a buildup of juices or grease under equipment or in grease traps. In a mausoleum it could be in flower vases or, bluntly, in human cadavers in extreme cases. It could even be an outside source in the landscape, which could also be the case for the fungus gnats. Fungus gnats often will be breeding in the wet soil of potted interior plants, as well as on any growth of fungus or mildew where water leaks are present. 

It is very important to determine where the source is. You can easily kill the adult flies and gnats with a mist of pyrethrum, but they will be replaced quickly by new adult flies emerging from the source of the problem, and insecticides and fogging will generally not affect the larvae that are developing in some hidden place. You may use UV light traps to monitor for these flies, which will be drawn to the UV light and caught on the glue pads, and this may help you to narrow the search for the source. A very careful inspection may also lead you to where you are finding the most flies and ultimately to the source. If you do suspect plumbing problems a qualified plumber should be brought in to inspect the pipes, and this can be done with a camera that moves through the plumbing. 


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