All of my houseplants have turned brown on the tips. I also have little gnats flying around them. I have sprayed and no results. What could this be caused by?
Even though brown tips can indicate dry indoor air, it sounds as if you have been overwatering your plants and brown tips and fungus gnats are the result. Fungus gnats are tiny black flying insects that looks like mosquitoes and are more of an annoyance. They lay their eggs in the soil which turn into 1/4″ white larvae that thrive on fungi and decaying roots. After they pupate, they emerge from the soil as tiny flying gnats. They like consistent moist soil and are an indicator that the soil has been too wet.
Control fungus gnats
Because the larvae need moist soil to reproduce, let the soil dry out between waterings. Household insecticide sprays can be applied to the soil surface. Products such as BT (israelensis) sold as Gnatrol, Knock-Out Gnats will also take care of the larval stage. Be aware the stuff smells bad. Use the mixture (BT & water) as a soil drench- or use insecticidal soap recipe - see below. You may have to apply more than once. To get rid of the adult flying insects, use yellow or blue sticky cards that fungus gnats are attracted to.
Here’s a recipe for a soil drench for fungus gnats.
1 qt of warm water
2 tBsp of insecticidal soap
soak the the soil -not the foliage. Apply once a month until problem is elliminated.
Another recipe is: mix is 1 qt of water to 1 tsp liquid houseshold bleach.