Wats up Overgrow fam,
I have a fungus gnat issue and am looking for some advice on how to really get it under control. I’ve applied LAB a few times. Although it made a slight difference, the gnats are there and back with a vengeance.
I picked up some Rove beetles and a trio of beneficial nematodes. My question is. Should I use the rove beetles first and then add the nematodes? Or vice versa?
Wouldn’t the nematodes end up going after the gnats AND beetles anyways?
Try neem oil works great…don’t use in flower to much or towards the end.
This will stop them for as long as you keep them in your soil. I sometimes transfer them from grow bags to new moms and freshly potted cuts. Scoop a couple spoonfuls onto a small white paper plate or something and I use a $30 USB microscope to verify there are at least a few tromping around in the soil and put them to work. I occasionally have a gnat near a kitchen sink or laundry room sink as do most homes but NONE in my grow area once you give them a week or so to break the breeding cycle. I usually buy a fresh batch annually and want some along with nematodes and general spider mite predators to use on planter veggies I do on my patio in a couple weeks.
Great for checking trichs too using my phone.
For me the trinity is the sticky yellow cards, DE (but you have to bottom water) and Bti (Bacillus thuringiensis).
I also found that if I positioned my circ. fan correctly, it killed a lot!
Cheers
G
Nematodes will vary in quality and viability based on who & where you order them from. Amazon ordered nematodes that are sitting in extreme temperatures in both the warehouse and in shipping will probably not be the most reliable. Ordering nematodes from a reputable vendor will be a bit more costly & shipping will factor into the price as well. May be cheaper and easier to just change cultural conditions and use BTi if you’re not in a greenhouse or something like that but if you’re really set on biological control using predators then nematodes + Stratiolaelaps seems to me a better choice as was linked above.
I purchased them from Arbico. Not sure if anyone is familiar with them. I’m fairly new to organics, so this is really just exciting to have to use a bug to control a bug lol.
But I like the afore mentioned suggestion about pairing the nematodes with mites thanks @Jasper.
I have faith this will get sorted out. Thanks for the suggestions everyone.
I’m with @Gpaw on this one. Yellow sticky traps for the airborne adults, mosquito bits(BTI) brewed and watered into the soil for the babies, and maybe some diatomaceous earth on dry surfaces…just because.
I’ve went a few rounds with these buggers on more than one occasion. And I always win! 
Ecological Labs AEL20036 Microbe Lift Mosquito Control Aquarium Treatment, 2-Ounce https://a.co/d/aEN4Y0c
Combine the BTi with sticky traps and good air circulation, guaranteed you’ll diminish their numbers drastically. DE only works if it’s dry. I use it but mainly for its silica value.
I have annual wars with fungus gnats. Everytime I add compost they pop back up again. Gnats seem to be attracted to light, similar like a moth to a flame. I catch alot airborne and right around my lights so that’s where I hang most of the sticky cards. Healthy organic substrate will always attract gnats. Unfortunately it’s one of the catch 22’s with LOS.
Neem oil works kinda. For me, I don’t spray the plants, I spray my mulch layer. It’ll piss them off and make them go airborne or keep them airborne and then I can get them in the cards. But if you don’t have a mulch layer, I’d definitely advise against putting neem oil in your soil. Neem meal works better for in soil defense.
BTI is the answer for fungus gnats. Predators work too but are expensive unless you’re getting them from your homemade vermicompost.
Sprinkle your soil evenly with the mosquito bits and scratch it into the top inch of your soil. If you can add a fan blowing on the soil surface even better. The BTI isn’t a contact kill but it will break their lifecycle.
@BerryHigh I use “Aquabac” pellets on the soil surface and will soak it to make a “fuck you infestation” tea.
Looks like this:
Think of it as pelleted mosquito dunks; I also use this for my 3x outdoor ponds and 4x water barrels 
Quick reading:
As an Airpot grower I feel your pain!
Cheers and all the best!!
Yellow sticky traps, BB microbes, mosquito bits, diatomaceous earth on top, predatory soil mites, nematodes work if you get the right ones and use them right away. Scan Mask was pretty good from amazon. Nematodes don’t care much what else is in the soil as long as it’s not biological killing like Imid.
Do a LAB/EM1 watering, too. Maybe plant enzymes. Get rid of the rotten shit the fungus gnats are eating cause the bacteria/fungus isn’t there to eat it instead.
Went and double checked. Mosquito bits are BTI. You just top dress with them pretty much and water them in. I put them on top of all my pots as IPM. I put the mosquito dunks (donut shaped same company) in the sump pump pits cause the garden is in the basement.
