We've been fighting fungus gnats in Pleb Lab. One or many of the plants in the lab were infested which is typically caused by overwatering. Overwatering can cause roots to rot and fungal growth in the soil which they feed on. This bacterial insecticide, which is known in the states as Mosquito Bits (chopped corn kernels covered in the bacteria), seems to be deciding the war. It's the latest weapon we've used after:
- vinegar + dish soap traps (very effective at catching adults)
- slow release nematodes
- yellow sticky traps
- watering (some) plants from the bottom to let the top soil dry (where they lay eggs)
- a layer of diatomaceous earth on top of the soil
- car also bought some ultraviolet light traps
There was a significant drop off following treatment with mosquito bits. The vinegar traps and the yellow sticky traps both worked well at catching adults, but I find the yellow traps hard to look at and annoying to place. The diatomaceous earth and nematodes might be working but most of our success is correlated with watering the plants in a mosquito bits tea. And the ultraviolet light traps caught a few but not many.
The bacteria is supposed to be relatively selective in killing larvae according to wikipedia, which is pretty awesome considering the effectiveness, but I'm stil worried that BTI may kill biodiversity in the soil so I may inoculate them with some beneficial microbes when it's over.
Also, fun fact: fungus gnats practice paternal genome elimination.[1] Meaning, the males of the species only pass along their mother's genetic material. I spent some time trying to understand why PGE has evolved independently several times, and only in some species, but it's too complicated for a late night nerd sesh. tl;dr is meiotic drive, a form of intragenomic conflict or selfish genes, and other stuff that's specific to insects.[2]
https://en.wikipedia.org/wiki/Sciaridae#Mating_and_genetics ↩
I bet there is some great hard sci-fi involving selfish genes. ↩