Fungus gnats

Since this is the time of year many of us are bringing in tender plants to over-winter indoors, thought this thread from the Brug Forum might be useful: http://davesgarden.com/forums/t/550226/

Yellow sticky traps work well, and also sundew plants.

I have one pot where I just can't seem to get rid of the fungus gnats, despite using yellow sticky traps and the gnats-be-gone stuff from Gardens Alive (I forget what it's called at the moment). However, you know how they are pretty easy to catch and smoosh, because they fly too slowly? Well, today I found a way to get rid of a great deal of them. I simply used one finger to disturb the soil while holding my vacuum cleaner attachment (the long skinny one) just above soil level. Sucked those babies right up as they flew up from the soil! LOL!!!

great idea, kbaumle!

Oh Kylee, only you! Too darn funny! Now, what are you gonna do about the fungus gnat larvae?

Well, that's what the liquid stuff is for, but it doesn't seem to be working. Grrrr......

Consider a biological control.

I've been adding Murphy's Oil soap (1 capful per gallon) when watering my african violets, and it really knocks back the population of fungus gnats (I don't mind a few). They'd probably be gone altogether if I used it faithfully. I'm also adding diatomaceous earth to my potting mix (2 tsp per quart) to deter the larvae... Since I haven't repotted everything with added DE and didn't keep good track of which pots have it, I'm not sure if that's helping or not.

I saw a few gnats a few weeks ago, so I added some peroxide to my watering water (1 oz/1 quart of water) and then I've been doing that about every 2nd or 3rd watering. Haven't seen one in over a week.

I use Diatomaceaous Earth. I prefer to strategically place carnivorous plants around those little buggers though. Kill two birds with one stone. Reduce fungus gnat population and feed my babies!

Hypoaspsis miles, A Predatory Mite

That's what you want .. they eat the larvae of fungus gnats amongst other things. Here is a link:

http://www.ipmofalaska.com/files/hypoaspis.html

They are used in greenhouses as well as by Hermit Crab enthusiasts to get rid of bad mites in their crabitats. They REALLY work.

X

Very cool, X, will Hypoapsis miles work on 2 spotted mites and the other related mite vermin?

From what I know, they will eat the larvae of just about anything.

X

Ooops, Hypoapsis miles will do a number on Fungus gnats so it is a great biological control for them but it's not all that effective on Tetranychus urticae. Your choices for a biological control on T. urticae are Phytoseiulus persimilis, Neoseiulus californicus, Stethorus punctillum, or Orius insidiosus. Pirate bugs have always fascinated me so I'd probably try to track down the O. insidiosus. P. persimilis is more readily available. Actually, I don't know anyone who has gotten their hands on O. insidiosis and was sort of hoping Gerris might be the first to track it down and use it.

Here's a source for P. persimilis-
http://www.growquest.com/phytoseiulus_persimilis.htm

The product I buy to nail fungus gnats is Gnatrol. I find a little bit goes a long way and Gnatrol is easier to get your hands on than a product containing H. miles. This product's active ingredient is Bt var israelensis.

Here's a source for Gnatrol-
http://www.gtghydroponics.com/store/0-0-476.htm

I saw a source for O. insidiosus, I will try to find it again. It is a cool bug under a stereoscope, indeed.

In my Master Gardening class, someone asked the same question and the instructor suggested removing the top 1" of soil from the plant and be careful to not overwater. She said overwatering was the main culprit. I did as she suggested and put up a couple yellow sticky traps. Their populations have plummeted.

You will repeatedly be removing the top inch of soil and adding fresh. The populations will plummet because you've removed a vast majority larvae of the gnat which will generally be concentrated to that area but there will always be a few that were deeper.

The other issue is that there are many species of plants in which you must "over water" to meet the cultural requirements. Many carnivorous plants come to mind off the top of my head but there are others.

Hey BugMan, did you get any O. insidiosus yet? I am dying to find out how those work.

As requested:

http://store.arbico-organics.com/1117001.html

I have a few. I water with 1:4 solution of peroxide:water for the larvae and put out small containers of mountain dew for the gnats. They dive in and drown, because they're attracted to the yellow color.

Hey BugMan! Did you ever try the O. insidiosus? Did anyone try it?