Can anyone provide possible solutions to keeping Fungus Gnats under control, I try to keep water levels at a suitable depth to prevent algae growth on perlite surface. We have a 1000GAL res mixed in with Garden Friendly Fungicide and Microble lift BMC. The only thing that I have use that directly reduces/eliminates the Gnat population is a synthetic insecticide (Acetamiprid).
I want to eventually phase out the use of this synthetic spray and go for a more organic option. If anyone can suggest a solution to this issue without the use of Nematodes please let me know, thank you.
by KyleDehBout
12 Comments
Is the water permanent? Still or flowing? Because the most effective way to kill off gnats is letting the soil dry out.
Find yourself some BTI (Bacillus Thuringiensis Var. Israelensis)
I had a friend who used raw potato to draw them away from roots and hydrogen peroxide solution (diluted). He also put cinnamon in the soil.
I think it worked for him. At least he never mentioned them again.
Nematodes or bti.
You sure they are FG? Looks like possible shore fly. FG will not bite/feed on leaves, only damage is from larvae in the roots
Adding mosquito dunks to your water will kill fungus gnats dead. It’s not even a synthetic chemical it is a bacteria and their toxins.
I added them to our fertilizer 100x stock tanks in a filter sock and it still worked.
I mix some mustard meal into my perlite when I mulch on top. Helps and also feeds.
Are they laying eggs and larvae eating the roots? It looks like it may just be adults eating the algae but laying somewhere else. Either way, you can lightly rake the perlite to mix the algae around. Adding a strong fan will keep the adults away from laying eggs.
Are you growing in heavy perlite?
Nematodes or dunks
Nematodes will make short work of this …. The rest of your options are moot at best.
Consider sand in the next bed it does fine with dry backs between waterings. r/sandponics for info.