Help, I have had fugus gnats for about 6 months. They started from me overwatering some african violets. I let everything dry out but still the gnats stuck around. I put all my plants outside for the summer and I still have gnats flying in the house. I heard that they might have moved into my drains so treated the drains with ammonia. The gnats are still here. Anyone have any ideas?
Check window seals, doors to the great outdoors, under the sink, ect... If you have any areas that are moist and stay moist then they have likely moved in there. I would treat any bathroom drains also. Lorax suggested powdered cinnamon on top of my plant pots when I was having your issue - which cut back on the population due to less mold for them - and Saltcedar sent me to this wonderful site on these buggers: http://insects.tamu.edu/extension/bulletins/uc/uc-028.html. Maybe these might help you? The cinnamon kills molds which helps curb breeding in your plant pots. Also those sticky fly papers you can buy and pin up seem to work in catching them - although not very effectively unless you put them in areas with high populations. Note: If you have any pets, check their areas...pets can be messy and often leave water/food messes which can mold. Anything that can mold will mold with these little guys around - and if it molds they breed...
I've found the best way of controlling them is spiders and centipedes. Any time you find one of either in the house, put it in the pots that the fungus gnats are breeding in. Takes a little time (a few weeks), but that's how I managed to deal with an infestation.
