What kills fungus gnat larvae and eggs?

Hi Everybody,

I've been battling fungus gnats for months. I've tried many different products. Everything I try kills the gnats themselves very easily but they always reappear after a day or two. So, today I just noticed a bunch of little larvae SOB's crawling around some peat pellets that contained cuttings. I started spraying them with the different stuff I had on hand and nothing even phased them. I sprayed them with neem and they didn't even notice. Bleach didn't bother them either.

I think I could get rid of these jerks if I could kill the larva and eggs. I really appreciate any advice.

Thanks

gnatrol and nematodes

Thanks inflorescence,

Can you or any one else please reccommend a place to purchase gnatrol, nematodes and BTI dunks?

Peace

I have took to freezing my soil and amendments below 0 degrees F for 3 days to break the cycle I have not seen a fungus gnat in a year.

That's an interesting idea octodiem. You must have an extra deep freeze at your house or something. If I stuck my soiless mix in my kitchen freezer I would have some splaining to do to the old lady.

Mosquito dunks you can get at Lowes and Home depot. I think 1/4 dunk will make 5 gallons. Catapiller killer bacillus will not control gnat larvae.

You can kill the fungus gnats with a variety of insecticides (pyrethrines work well), but you won't get rid of them unless you also kill the larvae in the soil.
A fungus gnat only lives 7 to 10 days. During that period, the females are capable of laying 300 eggs, that become larvae. They live in the soil and feed on dead, organic matter. They also feed on finer root hairs, and that is really the only nuisance they cause.

Best way to get rid of the larvae, stop growing in soil. It's their natural habitat, and once they've moved in they're hard to get rid off.
If you use soil anyway, make sure to use sterilized soil, so that you won't bring the gnats into your garden.
If you got them anyway, try the following.
The top soil layer is where the adult fungus gnats plant their eggs. Covering the top soil with a layer of sand or similar makes it difficult for them to reproduce. It won't stop them from reproducing, but it will limit their numbers and make it easier to kill them off in other ways.
The larvae needs a high level of humidity to survive. Therefore, let the soil dry out as much as possible between waterings. This will kill a high amount of the larvae population.
By flushing the soil, you will also be able to get rid of a lot of larvae. Simply water your nutrient solution until run-off, and send the run-off (with larvae) down the drains.
As octodiem said, the gnats like heat and hates cold. In the winter time, putting your plants outdoor a cold night will kill both adult gnats and larvae.
The bacteria Bacillus Thuringiensis attacks the larvae and prevents them from feeding. This is your best bet to actually get rid of the gnats. Bacillus Thuringiensis can be found in various insecticide products, since they equally attack several other parasites in the soil. When I had gnats, I used this product from Hydrogarden, which worked well:




So there's your check-list:

Spray the plants and top soil with pyrethrines to kill off adult Gnats.

Cover the top soil with an inert substance (non-organic) to prevent the Gnats from placing their eggs.

Dry out the soil between waterings.

Add Bacillus Thuringiensis to your nutrient solution.

In theory, this should take care of the problem.

Put one of these in your growroom and leave it there. They'll all disappear.

Those work awesome for flying insects and I actually wiped out my Fungus Gnat problem using a product like that here in Canada but also with the Fungus Gnat Powder you sprinkle on the surface of the soil to wipe out larvae and eggs.

It should be mentioned that fungus gnats themselves are pretty harmless, mostly feeding on decomposing organic matter at the soil's surface. It's the larvae that are predatory, mostly on cannabis roots. But I even had one outbreak so f'ing bad, the young gnat larvae (which are whitish slightly oblong) covered my young plants' growth tips and left the new leaves full of tiny holes.

Regarding treatment, I'd follow one of Rosy's idea--sand layer at the top of the pot (1-2cm) AND *STOP TOP-WATERING* for about 3 weeks if possible. If you have a saucer or some water runoff collection deal beneath your pots, water your plants by filling it and allowing the roots and capillary action to do their thing.

I have used this method, and have also used beneficial nematodes in the past, and both were equally effective. The sand's a lot cheaper.

Once you've broken their life cycle, in the absence of the original gnat vector (unsterilized soil, plants from outdoors), you can go back to top-watering.

Hey Rosy Cheeks, thanks for all the info. I really appreciate it. I'm going to follow that checklist.

Hey Glaydy, What is that thing and where can I get them? Thanks for stopping by.

Hey muddy waters, thanks for the info. I'm going to stop top watering now.

Peace

In an enclosed enviorment fungus gnats will damage your plants. Dont feel sorry for them kill them all. The larvae will taunt you saying "you cannot win, our war of attrition will wear you down every......."

And the old lady prefers the freezer to the oven.I am serious the plant sections of stores are fungus gnat breeding grounds. I know fungus Gnats here are not a native species. # days at sub zero will kill the pesky insurgents and kill there off spring no more taunting pointing and horrific vidios of my girls being abused. Serious freezing works. Please donot freeze plants.

you can use Hydrogen peroxide to kill em. Just get some from drug store or grocery store for a buck. the 3% solution is most common. Then mix it 4 to 1 with water. 1 cup peroxide to 4 cups of water. Pour the mix into your soil and watch it fizz. It kills larvae and eggs on contact and also once the h202 breaks down to oxygen which your roots will love. Its a cheap and simple solution which can help your plants a good bit. Besides killing them, h202 isnt toxic to your plants and once broke down is beneficial to your plants





Nevermind

gnatrol, skeeter dunks, hotshot nopeststrips, SMC, SM-90......if your in soil you may also want to try putting a nice thick layer of perlite on the top of the pot and swithch to bottom feeding...this will reduce the moisture from the surface area of your medium..(the place those critters like to hang out)...adding all of the products will give you a heavy arsenal for the fight towards eradication!! Goodluck DLB

I actually tried all these things fungus gnats are not native here. my infestation came from an amendment, mushroom compost I suspect. Soon everything was infested I did some reading and the key is to interrupt the life cycle. Several times Gnatrol, pest strips ,sand , dunks, diatoms sticky traps…. All came into play This is a constant question fungus gnat control. Why control when you can eradicate?

since the gnats came from medium i would just use H202 ( hydrogen peroxide). It will pentrate the soil and kill eggs and larvae, then all you gotta do is worry about the ones flying which can be taken care of with NPS. but since problem is your medium , kill all of em in medium






Nevermind

I had this problem really bad with my areo ponics. I tried neem and all that and what really works the best is Safer brand Cattapiller Killer. This product is inert to the plants and humans, but not larve. I sprayed my plants first and then they came back. Then I decided to dunk my roots in the solution because the bugs were laying larve in my roots. This worked like a charm and didn't stunt my plants at all. Just follow the instuctions the same as you would if you were fighting catapillers. Best solution possible with no effects on your flowers or self.

Mr. Nevermind said:

you can use Hydrogen peroxide to kill em. Just get some from drug store or grocery store for a buck. the 3% solution is most common. Then mix it 4 to 1 with water. 1 cup peroxide to 4 cups of water. Pour the mix into your soil and watch it fizz. It kills larvae and eggs on contact and also once the h202 breaks down to oxygen which your roots will love. Its a cheap and simple solution which can help your plants a good bit. Besides killing them, h202 isnt toxic to your plants and once broke down is beneficial to your plants





Nevermind

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i believe i might be having some bug problems MR NEvermind.im growing organic and heard that it was very bad to use peroxide when organic..so im a little scared and confuzed???
1cup of peroxide seems so much to me i m just scared of killing one of the 2 plants i got. If what u say is true this could help me out alot.
should i do this while growing organic?

Diatamacious earth would probably do it as well.