I got some stuff called Gnatrol a while back but haven't needed to use it yet. It's some kind of bacterial root drench and is supposed to be really good.
I looked it up. This is a little different version I guess. It's all over the web.
Gnatrol WDG (Water Dispersible Granule) biological larvicide offers the same effective control of fungus gnat larvae that growers expect from Gnatrol, but with added product benefits.
Gnatrol WDG is a biological control for fungus gnat larvae. It contains a variety of bacillus thuringiensis bacteria that kills most gnat larvae. Apply as a soil drench or add to the nutrient solution of your growing system. Does not kill adult fungus gnats, but once the larvae is killed, the adults will quickly die off.
Can be used up to the day of harvest on all edible plants.
Might try that on the indoors. Until this indoor run ive never had fungus gnats. Ever. Im worried they might travel to the light dep or full term.
I believe i got them with some soil. A new brand.
And talking to the guys at the grow store theyve seen a lot of customers asking about fungus gnat controls. Im thinking the store might be now infested. Does that make sense?
If the store has bags of soil in there or attached storage area there could be lots of bags infested and that's where most get them from. Any tear or breather hole in the bag is a nice place for a pregnant lady gnat to lay her eggs and start an infestation. Some bags sit for a year or longer before being bought so could be chock full of gnats.
I test for gnat larva by scooping a tsp of damp soil just under the surface an inch or two then putting that into a glass that I fill part way, stir then fill right to the brim so some stuff floats on top. Use a white paper towel and lay on top for a sec to pick up the flotsam then examine it with something like a 30x scope which is one I have. The larva look like tiny translucent grubs with two tiny black dots at one end. If you see those you got gnats. So check bags before use and don't store your bags anywhere near your plants.
Stick lots of sticky traps in the pots and hang some on the walls around the plants to knock back the adult population but the only way to win is to wipe out their young before they emerge and mate. That's all the adults do is screw, lay eggs on the soil and die. They don't feed as adults ergo no damage to your plants leaves. The roots are getting savaged tho from the larva. As the adults emerge from the soil they sit for a bit to lettheir wings dry then fly up to roost a bit and are attracted to the yellow traps as a place to land. The last place they'll ever land Muhahahahah!
Good luck!
