Gnats

Bukvičák

Well-Known Member
I was in the same boat. Battling fungus gnats. I had tried everything, then @TintEastwood recommended a cheap solution. I got this stuff off of AMZ, and it has some serious knock down power!.. I only use 12-13 drops per 50 gallons, and it killed all the larvae in the runoff tray with just one application. I still check every day, and see nothing but dead ones. I've never seen this kind of knock out this quick with anything else i've tried. AND, it's cheap, goes a hell of a long ways for the money. I can see the dead bodies in groups floating on top of the run off. I scoop up a sample, and check for life under the microscope... all dead. I used to use mosquito bits, neem oil drenches, etc., but always found live ones under the scope. Have not seen one live one since starting this application.
Edit: I still use large sticky traps on every plant to monitor adult activity, and it has dropped off dramatically. I haven't seen a flyer in days.



View attachment 5052208View attachment 5052209
Those do not look like gnats, all you need is yellow sticky tape and hydrogen peroxide if your medium allows it…
 

DoubleAtotheRON

Well-Known Member
Those do not look like gnats, all you need is yellow sticky tape and hydrogen peroxide if your medium allows it…
It’s the gnat larvae in the pic. They get flushed out of the soil when I feed. When I’m treating a pest like this, and the plant is ready, I’ll flush the shit out of them. The dead larvae get washed out of the soil.
 

Kushash

Well-Known Member
It’s the gnat larvae in the pic. They get flushed out of the soil when I feed. When I’m treating a pest like this, and the plant is ready, I’ll flush the shit out of them. The dead larvae get washed out of the soil.
I'm wondering the same thing about the pupa in the pics. They look more like fruit fly pupa.
 

DoubleAtotheRON

Well-Known Member
I'm wondering the same thing about the pupa in the pics. They look more like fruit fly pupa.
Nope, I've checked the adults under the microscope. Straight up Fungus Gnats. Not uncommon with the soil I always get. But, I think I have them under control now going into flower.
 

jondamon

Well-Known Member
It’s the gnat larvae in the pic. They get flushed out of the soil when I feed. When I’m treating a pest like this, and the plant is ready, I’ll flush the shit out of them. The dead larvae get washed out of the soil.
They aren’t gnat larvae. They are springtails. Lol.

gnat larvae are translucent grubs with a black dot on the head.

First part of any pest knock down is correct identification.
 

simpleleaf

Well-Known Member
Screw the home remedies. Any BTi product, (not BTk), like Gnatrol, mosquito dunks or that good stuff @DoubleAtotheRON mentions above gets rid of them quick. Just a bacteria so won't affect the plants or the buds. Also used to spray over cities for mosquito control so safe as anything you'll find.



Neem oil is half-assed too but the sink drains is right on. My basement sump was open to my grow room and I had gnat problems for ages until I noticed adults coming out of that area. Built a cover with filtered vents so my room air could get in without gnats and the problem went away. Bags of soil or even soilless media can be infested with gnats so keep them far away from the grow space and inspect for gnats.

Just tried Gnatrol on springtails that are killing some small plants and that didn't work at all so let all the plants dry right out until the leaves drooped badly then watered about 2/3 of a usual dose by pouring the water into their drip trays. Only did the plants as they drooped and also stirred a bunch of DE into the top 2" of the pots. Seems to be the best way to deal with those buggers short of chemical warfare.

:peace:

I successfully eliminated my gnats with 3 products. First I used H2O2 only (mixed to about 0.5%), and at first it seemed to reduce gnat populations, but later it seemed like they developed a resistance when populations seemed to increase. I continued the H2O2 and began adding a teaspoon of DE to each pot with each watering. I applied it by adding it to the nute mixture and stirring well which resulted in cloudy nutes (the runoff was clear, suggesting the DE was retained in the potting mix I use). The DE helped a great deal, but at around 3 weeks I still had a few fliers. I became impatient and did a soil drench with neem oil in the nutes, and shortly thereafter the flying gnats disappeared. If I recall correctly, I used the maximum label-recommended amount of neem. The gnats may have disappeared without the neem had I been more patient.

Several years ago I tried ground up mosquito dunks, and maybe I didn't use enough, but it failed to stop the gnats. If I recall correctly, I think I finally got rid of them with spinosad soil drench, but I have subsequently decided not to use the product since it's not approved in my state for cannabis.

I recently learned EDTA is known to reduce nematodes.
 
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beercan

Well-Known Member
This is just a thought i had but what if one put pots in a paint strainer bag and closed it up tight around whole pot and stem of plant?, it could still breathe and be watered fairly easily, but what about ones already in soil? Can they survive and multiply if they cant get out and still cause damage to roots or just eventually die off? Just a thought.....
 

DoubleAtotheRON

Well-Known Member
They aren’t gnat larvae. They are springtails. Lol.

gnat larvae are translucent grubs with a black dot on the head.

First part of any pest knock down is correct identification.
Yep... I was wrong.... however, they are dead, and that's all that matters. They are either Thrip larvae, or springtails. I sprayed for Thrips before I flipped, not because I saw evidence of them, but just part of the IPM.
 

beercan

Well-Known Member
I was in the same boat. Battling fungus gnats. I had tried everything, then @TintEastwood recommended a cheap solution. I got this stuff off of AMZ, and it has some serious knock down power!.. I only use 12-13 drops per 50 gallons, and it killed all the larvae in the runoff tray with just one application. I still check every day, and see nothing but dead ones. I've never seen this kind of knock out this quick with anything else i've tried. AND, it's cheap, goes a hell of a long ways for the money. I can see the dead bodies in groups floating on top of the run off. I scoop up a sample, and check for life under the microscope... all dead. I used to use mosquito bits, neem oil drenches, etc., but always found live ones under the scope. Have not seen one live one since starting this application.
Edit: I still use large sticky traps on every plant to monitor adult activity, and it has dropped off dramatically. I haven't seen a flyer in days.



View attachment 5052208View attachment 5052209
Is that the product that finally did it for ya?
 

Bukvičák

Well-Known Member
Yep... I was wrong.... however, they are dead, and that's all that matters. They are either Thrip larvae, or springtails. I sprayed for Thrips before I flipped, not because I saw evidence of them, but just part of the IPM.
Springtails are beneficial till some point, after that they are harmless. I have them in coco in runoff as well, they seem to extinct in mid flower. I have seen bilions of them in 5mm thick layer still not causing issues but it was different crop. You definitely do not want to get them out of hand but trying to get gid of them is just contraproductive. Two times valid for soil. I rarely get thrips out of medium, those rather come out of dirty environment or poor growspace pest protection. Gnats are bitches in sense of reproduction but they are very easy to eliminate especially in coco. You just add peroxide to your food and good bye. Wrap your pots in yellow tape and after two weeks you are gnat free. Against thrips you can use neem oil which pretty much makes them impotent, but you can use it only till flip. It seems to work on spider mites and aphids as well but those were outside in my garden. Aphids went from lush green to small black dry dot in three days. Problem with neem is that it ussually causes minor leaf burn and I do not like that smell and handling with that. It is also not safe for pregnant women. Pure neem is some really strong stuff.
 
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