I have heard both they don't harm the plants and they do - I would rather be safe than sorry. And even if they aren't harming the plants I don't wish to have a gnat explosion lol

I watered my chids with the Gnatrol solution as to not dilute it with more water. I repeated for 3 weeks. Let the solution run down in your humidity trays (if you have them) to kill what breeds in there as well. Seems like once you find a fungus gnat there are more to follow...kind of like fruit flies. They can come into the home on produce or from anywhere there is a door open long enough to allow one in (like a nano-second). I have some gnats on my lanai/pool cage area but my lizards take care of them out there. Keep us posted on how you get rid of them. :)

I usually soak my chids, which are growing in bark mulch, for ~ 10-15 minutes; I continued the process with BT in the water without adverse effects on any of my chids. I think rinsing the BT out might lessen or negate it's effectiveness.

Judi, it sounds like we are using the same methods. I'll give it a try. :thanx:

I've used diluted white vinegar, but only on non-orchids. The problem is all the air space hiding spots the gnats have with orchids. I also use yellow sticky traps, but home made, cheaper in the long run.

The gnats themselves do nothing. The larvae do no harm to the plants as long as they have plenty of fungus to graze on. Unfortunately, if the "goings are good" for them, the population grows pretty rapidly, they wipe out the fungis, and start working on roots!

Thanks for the info Ray!

Agreed! It's MY method as well as the sticky traps for the adults and some Sundews and Mexican Butterworts!

For all those who replied to my initial query, I have some follow-up. I ordered some "Gnatrol" over the internet and applied it using 2-3 tsp/gal of soak water and soaked the orchids for 10-15 minutes. I've done that twice now, 5 days apart and it has almost completely eliminated the problem. I hung new sticky tape after the second treatment and got almost no adults. I still see a few adults and plan to treat once more in the next day or so. For my money, I think the combination treatment is the way to go. The orchids show no adverse effects from the drenching in "Gnatrol"

One word on ordering the stuff. It was kind of hard to find but I did find a source that sold by the gallon ($86) out of California. I couldn't find any at local retail outlets, but that doesn't mean it's not available or in smaller quantity.

Thanks again for all comments and suggestions.:)

Thanks for the report George. I'll see if I can find some. My Sundew plant just bit the dust. I have been using a product that is a granule and sits in little cups thru out the orchid area. Not terribly effective. Smells like orange peel. Carol