Fungus gnats and diatomaceous earth?

[PleaseBloom]

Is it save to use food grade diatomaceous earth in my orchids? Supposedly it kills adults and larve from what I've read? I've only seen posts about houseplants with actual dirt in the pot and not bark so i'm curious if anyone had tried this on their orchids. I tried the dunks for months and it didnt really eliminate them. Also open to nematodes if anyone knows where to purchase and what kind...and if they work. NOTHING kills these things

[DeaC]

Look into Butterworts(Pinguicula). Mine were purchased from curiousplant.com and have kept gnats at bay. Varieties are endless and info on their site gave me success.

[estación seca]

If you place a fan blowing across your entire collection the adults will be blown away as they hatch. They are too weak to fly against the fan. They will be unable to return to lay eggs. Within 1 generation they will be gone.