One day as a teenager I was screwing around with the cattle prods they sell at the local farm supply store. I pushed the button a few times and nothing happened – no sparks, no noise. Clearly it doesn’t have batteries in it …
I learned something that day.
Bacillus thuringiensis israelensis is a bacteria that’s really good at killing mosquito, fungus gnat, and black fly larvae. It’s harmless to everything else and it’s the active ingredient in “Mosquito Dunks”.
You can break up a mosquito dunk into crumbles and soak them in a pitcher of water overnight to inoculate it with BTI. Water your plants with it to inoculate the soil and it’ll kill off the larvae – I go a little further and sprinkle crumbles over the soil in my pots to keep them inoculated.
It’s my go-to for dealing with fungus gnats in plants and I’ve never had it fail.