Fungus Gnats

So I just moved into this place last August. This is my first grow which I started about mid January. When we came to look at the place the previous tenants were growing herb in the basement, just a few clones at the time but enough to put up some red flags. So that lead me to believe that I'd probably run into issues with contamination or pests my first run as I have no idea how clean they are as people, let alone growers. I have indeed ran into some pests here about ten days into flower.... I believe they are fungus gnats. They look very much like the first image in this thread: https://www.icmag.com/ic/showthread.php?t=159960 They don't have a fat ass like those aphids seem and also don't have long pointy wings more round and proportionate to the size of the fly. I inspected all my plants and there are no bugs sitting on any of the leaves top or bottoms. Couldn't really see any larvea with my magnifier but really didn't know what to look for...

Just went into my room and saw three or four of them. Killed all with the hand clap method and shook all my plants to see if any more took flight. Tonight marks first sighting of any. A few plants are about ready for watering so the top few inches are pretty dried. Was gonna let the others dry out while making a swift and unrelenting battle plan.

What is the best most complete method for eradicating this bitches quick and fast. My options I was considering was Azamax dunk, H2O2 in a 1:4 ratio to water, mosquito dunk, and or a thin layer food grade diatomaceous earth on soil tops. I can probably do any combination of those listed as well...

Another question. I store my soil, Promix HP, in 30 gallon totes with the lid slightly cracked so I don't run into any bacteria or mold problems. Even though there isn't any food for the gnats in the soil and the soil isn't very moist will the gnats lay larvea in this soil or is the moist soil the only attractant? These are stored not in any of my grow rooms but in my basement about 5-10 feet from my grow room.

I like to post here in this Colorado section because helps me get to know my local people! Thanks for any help here stay medicated.

Gnatrol or mosquito dunks

Mosquito dunks lol suck a weird name. The name makes me think of being by a swamp strangling out a large mosquito under the water. Never heard of it before. Where do you acquire your mosquito dunks Snaps? Any specific chemical in the dunks that I'm looking for or they all the same?

Thanks for chiming in by the way. Sounds like you've answered this question many many times lol

Lowes or Home Depot have the dunks.

The dunks or gnatrol have the same active ingredient a bacterial agent bacillus thuringiensis (sp?)

Don't use dunks with h2o2 or you'll just kill the bacteria.

Hehe yea I was actually just noting that in my notebook that they contain the same main ingredient bacillus thuringiensis subspecies israelensis. Gnatrol has 37.4% bacillus thuringiensis and Mosquito dunks, the ones I saw, had 10.31% bacillus thuringiensis.

Thanks mate. Only saw about three in my room so hopefully I'll stomp these suckers out quick!

Now I live in Seattle. Very humid all the time. I am constantly fighting these things. If ur a soil guy like me, the eggs could already be in the Frog Farm I buy. One good way to keep them at bay, let ur soil dry out. I use 6 and 10 gallon pots to flower in. I ususally water every 5-6 days, I'll go 7 depending how late in flower and how droopy the leaves look. Now 1 and 3gallon pots are going to dry out faster, this is what I vegg in. Lot easier to let a vegging plant get dry than a flower. Most common mistake any gardener makes is watering to much. These are semi arid/desert acclimated plants, they don't live in a flood plain!

So I will let my plant dry out, then I will water tem normally. As I use rain water, I have and use mosquito dunks in my reservoir After watering, I spray the top of the soil with Azamax, especially were the dirt meets the pot, this is the easiest place for them to burrow. I use a 1 gallon sprayer, with 1.2ozs of Azamax. Spray the stock of the plant, the sides of the pot, ur weep holes were the water drains out, and leave a little in the drip tray. Then place gnat strips in ur soil like this. Then bomb your area, make sure u clean all the drip trays. You have heard how mosquito eggs can lay dormant for over 7 years, well the eggs of gnats are designed the same way. Clean ur pots and make sure you scrub the sides with soap and water.

You can do this again the next day, minus you feeding the plants. When I am spraying, I have the nozzle in stream mode so it penetrates the soil. The azamax kills larvae and acts like a barrier o keep the pest away. Probably do it 3 times before ur next watering and again let the plants dry out as much as possible!

Just feed sns 209 in veg and you won't see spider mites or gnats.

Gnatrol, gnat nix or perlite or sand (some top dressing that dries out fast so gnats won't lay eggs-they don't like wet surfaces) and let soil dry out real good between waterings. - also yellow sticky traps & a red glass of wine will attract and drown them.

Best of luck!

Extacie said:

Gnatrol, gnat nix or perlite or sand (some top dressing that dries out fast so gnats won't lay eggs-they don't like wet surfaces) and let soil dry out real good between waterings. - also yellow sticky traps & a red glass of wine will attract and drown them.

Best of luck!

Click to expand...

if you take a green light and shine it on those sticky pads through the night they become 100x more effective like a ghetto bug zapper.

We use spinosad which is cheap and it seems to keep them at bay just water with it until they are gone and then once a week after that. also a plus is that its omri certified organic and keeps down more then just the fungus gnats. You can also spray with it which will keep thrips away and those bastards can be common in CO just like PM and spideys.

Thanks for chiming in fellas. I grabbed some mosquito dunks and broke up two of them in halves. Crumbled those up and spread 1/2s over each plant, as I only have four plants. My homie recommended Spinosad and Azamax combo as well. I am letting three of the four dry out atm as one is so droopy ATM I had to water her. Felt bad for starving her of water lol.

Just cleaned out the humidifier I have in there there was at least 50 dead ones in there... So I suppose that's doing well to obliterate the adults atm lol. Also makes me think my infestation is worse than I initially thought as I've only seen a handful every time I go in there.

Yea glad I got fungus gnats instead of mites or thrips. This has got me into the preventative mindset which I wasn't really in before just was in the I'll deal with it if they come. Now just need to see them as a certainty unless I do something active to prevent them.

The gnat larvae is often found in premix soils just FYI from my experience. And dunks with some yellow traps is all you need no need for poisons the traps catch the flyers and the bacteria kills baby's end of problem. Good luck