FUNGUS GNATS and How To Identify, Prevent and Destroy them – Cannabis Growing

Another pest control guide, today on Lex’s World, this time about Fungus gnats. Spelling for the last 3 chemicals I mention: Vectobac, Gnatrol, Bactimos. There’s …


  1. Disappointed with the title of the video as I was expecting to see actual gnats or bugs being shown. I have just harvested my cannabis plant and have tiny brown bugs under the leaves and I need to identify them and if possible treat the plant before drying. So on to another video I guess.

  2. I have these guys because I'm an outdoor grow. Now I live in an extremely moist environment. My plants medium is NOT over watered, but the surrounding outdoor soil is saturated. So these guys are EVERYWHERE. It's not a huge problem for my plants because I don't have many. I can tend individually.
    The big problem that NO one has talked about… These guys eat plant decay… They live on/ mate on the plants that their lay their eggs in the soil to.
    During this living and mating, they poop. What ever it is they eat and poop out, it leaves behind a black spot on the leaf. A day later, that black spot seems to "burn" through the leaf. If hundreds are flying about pooping – your plant has thousands of little holes through all the leaves. VERY BAD. I can tell it's stressing the plant out massively.
    I've tried to wash the black spots off before they eat through the leafs but its stained like black tar… 🙁

  3. I got a bag of mother earth and I just started getting fungus gnats. I think it's the bag cause I just started two more plants and noticed that there was a couple flying in the bag. Theres not many yet. I've heard neem oil is pretty good but which one? Theres a bunch on Amazon. Also my top soul doesnt dry out. I havent watered for about 5 days and it's barely starting to dry out. Anyone have any advice on why it's not drying out and the best neem oil.

  4. I stopped mixing my soil with big box store chicken and steer manure and 95% of my bug problems were gone. It's what is in the animal feed that is mostly to blame when you buy manure from the big chain marts. They harbor all sorts of critters.

  5. If you're having trouble telling the difference between Fungus Gnats and Root Aphids look at the difference in wing length and their flight behavior. Root Aphids have wings that are atleast 2x longer than their bodies and they normal dont actually fly around but glide. So if you see some buzzing around erratically it's most likely just a Fungus Gnat.

  6. I recently had a gnat problem on some plants, if you catch it early enough before they start to fly and use traps to catch any that are flying. What worked for me was digging out the first inch or two of dirt and whipping down the inside and outside of the pot with a wet paper towel and then with a dry one. I then replaced the dirt with fresh potting soil and finally I sprayed down the soil with a mixture of 16oz water, pinch of cayenne pepper, and 3 drops of dish soap. This method worked on plants in both veg and bud stage. There were probably thousands of them crawling around, the dirt and pot looked like it had a lice infestation to put it into perspective. 24 hours after using this technique there was not one left.

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