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a guide to COCO and Fungus Gnats (little black flies)

Ok so just about finishing my 1st coco grow, and pretty much from the start i had a few of these little black fly's, there wernt bothering me so i didn't do anything about it. Now im a week from harvest and my grow room is infested with them not to mention they are flying around the rest of my house to! there are hundreds of them stuck in all my sticky buds and it doesnt look to tasty anymore! I read a few thread that had mentioned them and preventions, but i thought i would make this thread so it can be stickyed so all coco newbies can prevent this from happening to them!

What are fungas gnats?

Fungus gnats are small, dark, short-lived flies. The larvae of fungus gnats feed on plant roots and fungi, which aids in the decomposition of organic matter. The adults are 2–5 mm long and are important pollinators that can help spread mushroom spores as well as plant pollen.

How to PREVENT them?

Fungas gnats lay larvae in the top inch or two of moist soil. they then hatch and fly around to breed before returning to the CoCo to lay more eggs. To prevent this, simply dress the top of your coco with an inch of perlite, vercumlite or sand ( so that it stays dry) and then they will not survive here. I also recommend getting a sticky fly trap to hang in your room to catch any straglers before they end up in your buds!

So there you go, please every one who grows coco, TOP DRESS YOUR POTS! and it will prevent an outbreak of mostly harmless, but annoying gnats!

Trauerfliege.JPG
 

Snow Crash

Active member
Veteran
I tried Gnatnix with moderate success. Better than diatomaceous earth at least, but still not 100% effective.


Real treatment requires multiple areas of attack.

1. Keep the area around the grow clean. This means removing fallen fruit from the trees in the back yard. Keeping the kitchen spotless. Not forgetting about that slice of tomato between the stove and the cabinet...

2. Top dress the media, or better yet, cover it and run your drippers beneath.

3. Use yellow sticky traps to help trap adult flies in the grow chamber and monitor their population.

4. Use a root drench product like gnatrol to control larvae.

5. Use a sticky stem product like Tree Tanglefoot to collect young flies as they exit the media.

If you can keep their populations low in the surrounding area, keep them from getting into the media, attack them as adults, young, and as larvae, then you'll have the best chance at fending off an infestation.
 

Treetroit City

Moderately Super
Veteran
Nematodes nematodes nematodes.

Top dressing will not eliminate them if you have drainage holes in your pots.
 

Coconutz

Active member
Veteran
Sm90 start to finish will prevent bugs and keep the roots clean
Grow-More E-Z Wet SE also works for soft bodies from what Im told
 

gaiusmarius

me
Veteran
i find letting my coco go dry is the best way to knock them out. just turn the pump off for a couple of days, till the pots are light, but the plants are still looking ok, then water again and you will find the population has all but gone. but yeah mosquito drenches work too. nematodes are also nice for keeping them down.
 

Mikenite69

Active member
Veteran
Well this is a good thread! I just got those little fuckers in my coco there aren't a lot of them. I usually see like one of two flying around I have sprayed the hell out of them with Ed rosenthals zero tolerance which helped but didn't knock them out. Sprayed with neem didn't really help top dressed with perlite also didn't help. What I did was drenched the hell out of the coco with zero tolerance, sprayed all the plants with captn Lou and robs mighty bomb and used doctor doom fogger and I haven't seen anymore since knock on wood. Peace mike
 
myself , i run coco hempy style, so i only have one drainage hole which i have pvc pipe inserted into running to a drainage tub, so im guessing the gnats wont be able to crawl up that and lay eggs that way so top dressing should be enough for me. I can see how this would not be sufficient for other growing methods though! i have also read that just mixing some washing up liquid with water and watering your plants well with it, let it sit for a couple of hours, then flush out, will kill any gnat larve inside the coco. gota be worth a try!
 

farmari

Member
I put the yellow sticky paper on the coco surface, leaned up against the side wall of each plant container. Amazing how simple and effective they've been for me. The gnats love to land on them. I had a really bad infestation before... when I put a sticky strip down, I counted over 100 stuck to it within 24 hours from just one plant bucket... probably over 1000 total from all the traps.

Now I'll see a gnat here and there but usually they land on the trap before I see them. I don't think a gnat here and there is significant enough to cause damage as my best harvest ever (years of growing) had a number of gnats flying around in each plant bucket. But something has to keep their numbers low as they can quickly kill big healthy plants under some circumstances.

I tried beneficial nematodes but didn't notice a difference. Though I tried them because some people have had great success with them.
 
B

bigbufu

Ive had experience with gnats and got them away with various methods. The sand on top of the pot is solid and will knock out the flying ones as they are unable to reach the soil to reproduce etc. Also crushing up mosquito dunks and topping the pots with the crushed up dunk definitely helped as well and I now always layer my coco with the dunks just crush them up and toss some on top of the medium WAY BETTER RESULTS THAN KEEPING A DUNK IN YOUR REZ. To top is off I used azamax as a root drench and I havent seen those fuckers. Also a P-Bomb will knock out a good amount of the flyers if your population is getting out of control Id definitely throw some bombs in there. Anyways having the proper equipment and knowledge is key in knocking these pests out.

-AJ
 

dupester

New member
Try Mosquito Bits. Just sprinkle on top of coco/soil every three weeks, and water activates it.
But like snow crash said, keep everything clean! No standing water. I also dump a little bleach down every drain, toilet, and sink in the house once a week.
 

Chevy cHaze

Out Of Dankness Cometh Light
ICMag Donor
Veteran
You can look for products containing bacillus thuringiensis israelensis like Neudomueck f.ex.
They sell those products to keep ponds and stuff mosquito-free and it works with those gnats as well.
The larvae of the gnats in the coco/soil eat it and then it dissolves their digestive system.
then get the adult flies with yellow stickies and break the cycle with a perlite top layer.that worked for me perfectly.

sounds really harsh, but it does the job efficiently and it's not affecting the buds, so you can use it even during last weeks of flower.

Mine were all gone after a couple days.

good luck &take care

cc
 

medicalmj

Active member
Veteran
I just got back from the store with my usual predator nematodes and some of that stuff called gnat-nix. I have never tried before but its basicaly those growstones crushed really fine. Since they're made from recycled glass it's supposed to shred em like DE, but it can get wet.

I grow in 100% coco in airpots with multiple feeding per day (DTW) so keeping these fuckers at bay takes vigilance. I don't catch or see many but that's because I am proactive with the nematodes and will step it up if I start catching too many.

My hope is that this is one more tool to keep these fuckers in control. But will continue monthly (or more if needed) nematode applications.
 

Mister_D

Active member
Veteran
SM90 @ 5ml per gal. completely eliminated my gnat problem in about a week, and has kept it gone for over a year. I use it with every watering, veg through flush. Just do a through soaking of all of your plants to get all of the eggs.
 

medicalmj

Active member
Veteran
try neem oil.

My next tool I would consider would be the active ingredient in Neem, Azadarachtin, but I opt for Azamax or Azatrol over Neem when drenching. I use Neem for foliar and Azamax for drench.

But I have kept FGs at bay with only predator nematodes. Thankfully, for now anyway, that will be the extent of anything I put into the media. The only other thing I am doing is the top dressing of gnat-nix.
 

Weezard

Hawaiian Inebriatti
Veteran
As you formulate you plans of attack, here are a few facts to keep in mind.

1. The flyers do not eat.
Their sole function is to mate and lay eggs in, as yet, uninfected areas.
They do no damage to the plants other than laying eggs.
Yellow sticky traps immobilize them but only prevent new infestations.

2. You can have a large population of gnat larva munching your roots before a single flyer is seen!
Seeing flyers indicates that they are getting too crowded under the surface.
Only then will some of them become flyers.

3.A healthy, robust plant, can survive, and even thrive with an FG infestation of the roots.
But stress from anything else will be additive and doing things like over drying coco will give the larvae the upper hand.

So, protect your uninfected plants with a surface barrier before you see the first flyers.

Go after the larva tooth and nail.
Whatever it takes.
Nematodes and fungi will take out a light infestation, or at least control it.

For a really bad situation there's a sure fire wipe-out method but it's definitely not "organic".

Add a tablespoon of Adam's flea and tick shampoo to your first wetting when mixing soil, or coco.
That will deter the flyers, as will dryer sheets laid on the surface.
The flyers avoid it so, no new larval infests.

An existing larval mass will be completely purged by watering with a teaspoon of Cutter backyard Mosquito concentrated spray added to the watering.
It's a combination of Lambda-Cyhalothrin and a repellent.
Offers 4 weeks of Mosquito free, outdoor living
How safe that is, I do not know, but would not recommend it's use during flowering.

Now, It's all about prevention.
I use dryer sheets atop the coco and have not seen any Fungus gnats for a very long time.

Yeah, I know, proves nothing.
(No see any Tigers? Den dis Tiger chaser charm mus' work!) :)
Should they ever stop being effective, I'll post it. :)

Aloha y'all

Weezard

 

habeeb

follow your heart
ICMag Donor
Veteran
what worked for me,

gnatrol, but it needs to be shaken heavily in the water, or left for a long time to really get mixed in the solution

I've always wanted to try nematodes.

I hear the new thing in the organic section is adding neem cake to the mix, as it's the pressed seed for neem oil...


basically wipe the fuckers out, as the more rooms you work, the bigger the problem they become. also one can re-populate the whole problem again..
 
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