Fungus gnats

Can anyone tell me if these are “fungus gnats”, I recently was gone for about a week and when I came back my plant had a lot of these small gnats on it. I real in the grow bible on how to get rid of them if they’re fungus gnats but I can’t really tell. Sorry for the crappy pictures. I see them dead all over and on my plant but 99% of them on the plant have either been dead or not moving…not sure if they’re high or stuck in the resin or what…


look like fungus gnats to me

Hey thanks machyver…a little late on the reply but the website was having issues and I couldn’t log in. It was weird because all of them seemed to just die off naturally, I didnt have to do anything to treat them.

your lucky they didn’t harm your root system,… (larve)
IF,. you ever see this again, purchase a pack of “yellow sticky cards” as the yellow attracts gnats and many other unwanted pests… If they become too bad, you should use a soil drench… otherwise they have potential to cause really bad damage to your root system.
I won’t go into detail since lucky for you they died off. I battled these pests last season outdoor, as we had a super ass wet June… these gnats are mainly caused from wet / humid conditions. Usually from stormy weather. Sometimes from overwatering, as not too many of us growers a stupid enough to keep our plants drenched all the time. Learned alot. Every season, learn something new.

Find some of this: Read the whole description.

Diatomaceous Earth “Food Grade” CODEX

This will solve your problem. You apply with a standard garden duster.

I just did my grow about a week ago with the DIATOMACEOS EARTH and it worked great. Thanks Latewood Problem solved!
The only thing is that it looked like it snowed in there…lol


Thanks guys, if they come back I will try them…I won’t be surprised…my shit is have never been out of my closet and there was a pill bug in the soil of my first plant…I was just thinking how…Same thing I was thinking when the gnats came around though too…

I got spider mites and LateWood told me about this stuff and boy did it ever work…


The Diatomaceous earth worked great for me also. I got to thinking about it and I am curious, has anyone tried a bug zapper with a yellow bulb instead of the U.V. bulb for fungus gnats? If so could you let me know how it worked?

I think I have fungus gnats too but I’m not sure if they’re fungus gnats or fruit flies. I seen little flies buzzing around and then a while later little white spider looking things crawling on the soil. My plants are pretty young not even a foot tall and one is already almost dead. Although that could be from other issues too. The leaves are turning yellow and starting to droop. I got the plants from a friend and he wasn’t taking very good care of them. I hate to see a marijuana plant die so I’m trying to save them. Any help would be much appreciated. Thanks

Diatomaceous earth you need to get some a.s.a.p and make sure you don’t get the DE for swimming pools ok
Make sure you dust under the leaves and dust the soil. This stuff works great.

Here is a link

B Safe

Ok, will do asap. I appreciate you taking the time to help me out.

Sounds like you are watering to much, the little things crawling are the larva of the gnats. Slow down watering and use the DE like he said.

So I think the fungus gnats cause some mold in my soil. There is a powdery substance on the soil. I can also see it through the drain holes

FYI, fungus gnats and mold in the soil are also often signs of over-watering.


I am a first time grower, with three plants in a closet lined with aluminum foil, and a layer of garbage bag on the floor, a fan and an ionizer. I had a bad case of fungus gnats, and I think I might have brought them in with the store bought soil I used first. I tried hydrogen peroxide, and that didn’t work, and I also let my plants dry out, and that didn’t get rid of them completely either. I heard about mosquito dunks, you crush them up and sprinkle them on the soil, and I also bought two fly paper strips and hung them up, too. After one day the fly paper strips were completely filled and I was shocked. You can’t always see those little suckers, but I evidently I had a worse infestation than I had thought. I looked closer down at the floor and I saw one crawling on the black garbage bag. I pulled the plants out of the closet and ripped out the garbage bag and ah hah! There were hundreds of them down there. So they don’t always need soil to attract them. They are attracted to moisture and dark places where fungus can grow. So I learned something. No more dark garbage bag plastic anywhere around my grow. Thought you all might like to know. Cheers!

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To take care of your fungus gnat problem, DE (Diatomaceous Earth) is the answer. I had the same problem on my first grow and everyone said to get DE. It definitely works! It is safe for your plants and some people even eat it. It’s a fine white powder and you just put it on the leaves (top and bottom). It will get all over everything, so don’t worry about it. I even mix it in with my soil to take care of any root fungus problems that might arise. You can order DE from Amazon or e-Bay. Good luck. Make sure you get the food grade and not the the stuff for swimming pools.

Thanks. I ordered some and it is on the way. I appreciate it.

This thread is old but if u used the DE it can leave a mildew like paste on top when u wet i think thats normal for the DE