Fungus Gnats versus Beneficial Nematodes

My favorite potting mix is an organic blend. The blend is also a favorite snack for fungus gnats. I tried using yellow sticky cards, vinegar traps, and sprays, A few jillion gnats ended their lives on the sticky cards, but I’m pretty sure the the bug spray was an aphrodisiac.
I had a lot of success de-bugging my last garden - we were down the street from a small lake & there were clouds of crane flies all over heck. There are also loads of hummingbirds in the area so I didn’t want to spray anything that might be toxic to the little dudes.
Beneficial nematodes to the rescue. There are approximately (maybe . . . opinions differ) 25,000 type of nematodes on our planet. Some of them are icky: tape worms, ring worms . . . ew. Enough of that.
There are, on the other hand, some very awesome nematodes that are invisible to the naked eye (great if you are bug-squeamish), and these magic, invisible nematodes enjoy snacking on my mortal enemy, fungus gnats.
The nematode I’ve had the most success with is Steinernema feltiae. They come commercially packaged in powder that you mix with water - several readily brands of pest remediation use this nematode. As the nematodes reduce the gnat population, they will die off. You can tell it is working when your yellow sticky cards remain yellow & not littered with gnat carcasses.
Just think of nematodes as invisible pets & let them loose to do their thing.

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