We’ve had a problem with fungus gnats inside and outside for the past month or so. At least seven of our neighbors have the same problem; I also noticed them in the windows at my dentist’s office and yesterday at a restaurant yesterday about 8 miles from here.
I’ve been told they’re coming from my houseplants, but I’ve checked the soil (I do not over water) and they’re not in the plants, however, I did purchase a granular product which I will place in the plant soil later today.
I occasionally see one flying through the air, but they’re mostly on windows. I’ve killed in excess of 50 in a few minutes at the large window in our living room; go back a little while later, and they’re there again. An exterminator told me they’d disappear after frost. We’ve had frost; it slows them down for a day (as does rainy weather), but then they come right back. I’m really afraid that we’ll have to learn to live with them.
We do live in mushroom country (Kennett Square, PA), but we’ve been here for 12 years and have never had them until this year. Is it possible we’ve had just right weather conditions? What do you think? Any thoughts you have would be really appreciated.
PS: You’ve helped us with springtails about a year or so ago. Those are now under control. Thank you!
In fact FUNGUS GNATS routinely become a problem inside homes during the colder months of the year. No doubt houseplants are the most common location where they'll congregate and breed. This FUNGUS GNAT IN PLANTS problem discusses the best option for treating soil. I prefer this treatment over granules because it works immediately. And though you don't think the plants are the problem, it's imperative you start there and then branch out to other areas of the home if treating the plant soil doesn't solve the problem. Remember, you won't see any gnats in the plants because they're only active there when developing as young larvae. Once they hatch out as adults, they'll leave the plants and rarely if ever return. 99.9% of their life will be spent flying around the house and only females will forage to places where they can lay eggs like the soil and once done, they'll leave right away. So with this in mind, it's important to treat the soil because it's usually a hot spot but more important will be the spots where they're seen. And from what you're describing, this sounds likes it the windows.
So what can you do for the windows? Fortunately there are two treatment options you should consider that would no doubt help. The first would be to lightly apply a pre-mixed formulation of BIFEN IT to the window frame around the glass. This active is odorless, lasts a long time when used inside the home and is very active on flies and gnats. You'd only need to mix a small amount, like .1/4 to 1/2 oz per gallon of water, so there would very little product being actually used to treat all the areas where they are active. I'd recommend mixing up a tank full, maybe just 1/2 gallon to start, and then using a paint brush to lightly apply the mixture to the target sites. Bifen can actually be used on plants so you could treat the houseplants with any left over spray by drenching the soil. Also, Bifen is great outside on the landscape vegetation for most any pest including ants and mosquitoes.
The second option would be to install some AEROSOL MACHINES we have listed in this general GNAT POST. This approach would be easier to employ but more general and if you don't have enough machines distributed around the home, the flies will no doubt still be a problem.
In the end, trying to locate the source of the moisture would be ideal. Once dried or treated, you should be able to stop the cycle. I mostly see where houseplants are to blame but other areas that can easily cause a problem include garbage disposal systems found in most kitchen sinks, garbage bin areas, kitty litter, refrigerators, ice making machines, hot water heaters, air blowing systems and humidifiers or dehumidifiers. Remember, the fungus gnat will only remain in these areas as a larvae. Once an adult, it will only go back to such an area to lay eggs but will spend 99.9% of it's life away from nesting sites so don't think you need to see them on the plants for this to be their nest site because that won't happen.
Here are direct links to the information and products listed above:
Fungus Gnat Control: http://www.bugspray.com/catalog/products/page306.html#fungus_flies
How to treat Fungus Gnats in plants: http://www.bugspray.net/fungus-gnats/fungus-gnat-problem-in-plants-or-house.html
Bifen It: http://www.bugspray.com/item/bifen_it.html
Aerosol Machines: http://www.bugspray.com/catalog/products/page1813.html
How to treat Gnats in house: http://www.bugspray.net/gnats/gnat-problem-in-house.html