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Fungus gnats

If anyone ever tells you that fungus gants won't hurt your plants, they are wrong. I have caught a few larvae red handed working their way through my utric pots. I'm going to try the Bt strain (Bti or Bt H/14) designed to kill them. Has anyone tried this? The products I've seen are called "Gnatrol" and "Knock-out Gnats".
 
well, fungus nat larvae won't hurt them that's the best food source for them. they might hurt flytraps. if you don't want them, transplant a sundew in all of your utric pots and that should do it...
 
I wouldn't argue with Dodec. If he says that his plants (95% of which are Utrics) are being eaten by gnat larvae then in all probability his plants arebeing eaten by gnat larvae
 
Spec, I realize that the conventional wisdom is that they don't harm plants, but I've seen it with my own eyes! It was crawling across the surface of a pot of U. blanchetii mowing down the leaves. I also have suspicious little dead spots in a few other pots. Anyway, the flies are pretty annoying too.
 
the safest and fastest and best way to get rid of them is to flood your utrics in buckets for a couple of days.







I now believe you that they would harm the plants. they could eat all of the stolons!
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I'd get rid of them fast!
 
Flooding doesn't help, the little buggers seem to do best in Utric pots which I know Dodec has on a flood and dry cycle. I think the BT treatment might work, maybe predatory nematodes as an alternative
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Fungus gnat larvae do feed on roots and can cause root rot and plant decline.
 
Man, when insects attack CP it just seems unjust, Y'know?
 
I have an infestation too, but now the Drosera seem to be gaining the upper hand.....Or should I say upper tenticle?


Mwaaa haaa haaa haaaaa
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By the way, are these gnats the reason it looks like it snowed in my terrarium, or is that actual fungus or some sort of white Algae?
confused.gif
 
  • #10
Hi,

I just read a website that claimed that fungus gnats do indeed eat plants when the supply of fungi/molds run out.

It suggested a mechanical treatment that probably would be too much work for most people here (due to large collections), but could be tried for those who only have a couple of pots to worry about. Place a slice of potato flatly on the surface of the soil. I imagine alot of other fruits and veggies could be used. (maybe a banana peel would be better?) Within a day or 2, the gnats will congregate under the potato, where you can harvest them for disposal.

I'm guessing that using a slice that's a little past its prime might be best.

I can't speak to the effectiveness of this using food, but a couple of times in the past I have seen large numbers of larvae under leaves that had fallen from a couple of my houseplants. I'm talking a writhing mass.

Take care!

Chris
 
  • #11
I like the idea of something that will just knock them all out. It only takes one fly to start a new infestation. And since Bt is completely harmless to people I'm willing to give it a shot.

I'll let you know if it works.
 
  • #12
Well maybe the masses are correct after all. The damage that I had previously attributed to fungus gnats seems to be the result of thrips. Bastards, they can really tear through a utric.
 
  • #13
A 24 hour water dunk should work on them (thrips), no? And maybe placing flea collars in the cabinet or spraying with neem or any other favorite insect repellent while you are dunking the plants will maybe help get rid of them for good?

Take care!

Chris
 
  • #14
I had tried dunking them, but it wasn't very successful. For one thing I just have too many plants to dunk them all.

I'm trying a light spraying with some half strength diazinon. I have used it for aphids before with some success, although it killed some plants when I applied it too heavily.

I've been bad about follow-up spraying, so my aphids come back after a few months. After my move I am going to make a serious attempt to eradicate insect pests from my terrarium, spraying everything, then respraying at the appropriate interval to make sure the eggs also get nuked.

I also noticed a nasty little bunch of fugus gnats that were indeed eating the stolons. Gnats leaves slimy trails and the leaves just dissapear, whereas thrips make the slives silver with green spots, which eventually die.
 
  • #15
Out of curiosity........ How would you prevent your medium from floating off when you dunk the plant?
 
  • #16
I find that after a few months in a pot the mose/algae/fungi in the soil will hold it into a pretty solid block.
 
  • #17
Fungus gnats are a pain. When I was doing tissue culture bananas, nothing seemed to work on them. Then I bought a can of Raid or something similar. Look for something with several kinds of pesticide in them, like a combo of pyrethroids and organophosphates. The mixture, or cocktail, of chemicals seems to work.

Don't forget the fungicide!! They're just waiting around like little smiley faces ready to dive into a plant wound.
 
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