Question
Hi, the pots of my house plants seem to be infested with fungus gnats. The tiny bugs are always flying around everywhere and it's getting pretty annoying. Especially when I water the plants the bugs always come flying out and it seems impossible to stop them. I have looked up ways to kill these insects but nothing is really showing up. I have tried to make an apple cider vinegar trap but it doesn't appear to be working. I also have an insecticide based on pyrethrin, will this work? If not do you have any tips on how to effectively eliminate the fungus gnat problem with my plants? Thank you

Answer
Hongzhi,

You may have gotten some bad potting soil if you recently repotted them. If not you may be over watering them and that will cause root rot which attracts fungus gnats. Fungus gnats are in the same family as fruit gnats that show up out of no where if you leave overripe bananas on the kitchen counter. They are attracted by the scent and fungus gnats are attracted by the smell of rotting house plant roots. To eliminate them you can water your plants with 1/2 water, 1/2 rubbing alcohol which will kill the larva in the soil and cut back on how often you water them. Let them dry out more between waterings to eliminate the root rot. An hour after watering empty all excess water in the drain trays so they are not sitting in water constantly. That causes more root rot. They must dry out between waterings. If you have more questions feel free to write again. Good luck!

Darlene