How do I get rid of fungus gnats?!

[Phonelady]

Hi Everyone,
I have fungus gnats in my house plants. I've used the yellow sticky card, sand on the top layer of pots, neem oil spray and neem oil in the water so that it becomes a topical application. I've watered less and let the pots dry out, etc.
Is there a insecticide I can use in the soil to get rid of these things?
Thanks!
Carla

[Ray]

Almost any insecticide will do the trick, but you have to saturate the medium, and repeat the process three times at one-week intervals.

Some folks buy "Mosquito Dunks", soak one in water overnight to get the bacteria population up, and water with that. The Bacillus thuringiensis will kill the larvae.

[estación seca]

Another solution is to position a fan blowing across the soil of your plants. It doesn't have to be a stiff breeze. The gnats are weak fliers. They will not be able to land and lay more eggs. Soon they will be gone.

[Ray]

Let me also add that fungus gnats can be considered to be the orchid grower's "canary in the coal mine", indicating that it is time to repot something.

The larvae feed on fungus growing on decomposing organic matter; most likely the potting medium. When they have stripped that bare, they go after roots.

[Subrosa]

Will any of the plants tolerate the media drying out? Fungus gnats won't.

[orchidsarefun]

The best, cheapest, cleanest and most efficient method is to get yourself a pinguicula plant or 2.

[Phonelady]

Yea, I changed everybody's soil a couple of months back [what an expedition!] Unfortunately, the little buggers were able to survive somewhere in the place and re-infested all the newly re-potted plants. Sigh...

---------- Post added at 10:07 AM ---------- Previous post was at 10:06 AM ----------

Ohhh. A pinguicula plant looks kind of interesting.
Carla

[katrina]

If you're talking regular houseplants (not the orchids) and they are in a soiless, peat based mix...you are in for a battle. Fungus gnats love that mix! Best solution...use the mosquito dunks. I get the granules and soak them for a couple of days and then water with that solution...every watering...until it's been a few weeks since I've seen any of the gnats. We have a few large tropicals that spend the warm months outside and I get them every year...even after a fresh repot...and I do this treatment every fall. Works like a charm! You just need to make sure you use the solution long enough to make sure they are all gone.

[Ray]

Originally Posted by katrina

If you're talking regular houseplants (not the orchids) and they are in a soiless, peat based mix...you are in for a battle. Fungus gnats love that mix! Best solution...use the mosquito dunks. I get the granules and soak them for a couple of days and then water with that solution...every watering...until it's been a few weeks since I've seen any of the gnats. We have a few large tropicals that spend the warm months outside and I get them every year...even after a fresh repot...and I do this treatment every fall. Works like a charm! You just need to make sure you use the solution long enough to make sure they are all gone.

...and it's safe for you and any pets.

[katrina]

Originally Posted by Ray

...and it's safe for you and any pets.

Yep, and that is always a good thing.