Do fungus gnats eat your plants or just the decaying material?

I have a cactus pot plant in my living room and it has become infested with fungus gnats. I do not like to kill animals unless I absolutely have to, so I would like to know if they pose any threat to my cactus at all. If they don't I won't worry, but if they do I would like to get rid of them.Do fungus gnats eat your plants or just the decaying material?
The only guaranteed way to save your cactus is to sterilize another pot with all new cactus plant mixture.





Put gloves on and be very careful not to bruise the plant. With a gentle stream of water remove all the soil and gnat nest and eggs.





Replant it and just moist and pack the soil down to adhere to the roots. Let it sit in very mild sun light for a couple of weeks and then place it a very bright sunny window. Keep it moist for the first month and then let it dry out some like cactus like.





I had this happen and I tried everything and this was my only solution and it worked great, Once they are in there....you just can't kill them out.


Now this plant really took off this spring and summer from being outside.


Best wishes


DPDo fungus gnats eat your plants or just the decaying material?
The fungus gnat larva does eat the roots of plants. The plants eventually die.





Buy some ';Mosquito Dunks';, they're for controlling mosquitos in ponds. Break up one into powder and mix it with some water and water your cactus with this. They contain a beneficial bacteria that will live in the gut of the fungus gnat larva. The bacteria will kill the larva after a few days. Just water with it about once a week and eventually the fungus gnats will all die.
They eat the young roots that are just below the soil which then kills the plant off. Mild soapy water left on for about ten minutes then sprayed off will discourage their nesting in your soil.
The fungus gnats have laid eggs in your cactus. Are they hovering around the pot? They will eventually have an effect on your cactus. Maybe try repotting with some fresh potting mix.