Fungus Gnats

J

jochhe1998

Active Member
2com said:
(1; assume your media has fungus gnats in it...treat it accordingly)

Anyway:
-Wettable Sulfur (everywhere; medium/root zone, vegetation, trays/pots if you want)
-Bait mix (Water, apple cider vineger, sugar, some liquid soap/other surfactant)
-Sticky traps (yellow)
-H2O2 (additionally, this "breaks down" the decaying root/plant/organic matter that the larvae feed on". it's not just to 'kill' the larvae via contact.
-BT (the active ingredient in "mosquito dunks").

You should/need to do a combo of, say, three or more of these things. And you need to do it/keep it up for 30+ days to fully disrupt their entire life cycle.

Also, manually:
-You can suck them up with a shop vac after gently shaking the plant. Or spray'em with a mix of ISO-P and water.

@DoubleAtotheRON The "pluggable" brand usb microscope on ebay is a decent one, takes high def pics and video, built in led. If you have android phone you can connect it to that with a usb-OTG cable/adapter. Valuable tool.

Kill. All. Those. Fuckers.
Click to expand...
Love the enthusiasm.

So you think it would be more beneficial for me not to add any organics back into the system and just continue with H2O2 and BTI?

Also, have you had to do this for 30 days before?
 
2

2com

Well-Known Member
Each stage of the critter's life cycle has it's own "length". And each stage requires a different approach, and/or has multiple approaches that may work better or worse than the other, or benefit from using both.
I wouldn't go too overboard with the h2o2 (ie too frequently), depending on strength of mix (don't remember exactly what strength I used.)

But wettable sulfur powder is very cheap and is also something I think is a staple IPM product; everyone should have some.
Yellow sticky traps aren't that expensive. Get a 60 pack of the large ones (maybe...8"x4", can't remember) on amazon and you can cut them in half to get more out of them. They're double sided, too. Peel one side, use it, then cover it and peel the other side. Unless you hang it in "free air" where you can catch the fuckers on both sides. Definitely put some at soil/pot level, lay them on/across the lip or rim of the pot if you can, even with both sides exposed (sticky). The adults are constantly going into the medium to lay more eggs. So you get them coming and leaving.
They are attracted to the color yellow (and other bright colors I think, maybe), and they are attracted to light too. So, put the traps where grow light is hitting them (both below the canopy, like on pot rims, and hanging or placing them on walls or whatever).

Spray wettable sulfur mix (water, sulfur, and some surfactant - peppermint soap works great) on the top of the medium (maybe after water/feeding). Spray the planter drain holes. Spray the entire plant, bottom and top of leaves, and stalk -- but note when this dries it leaves a visual bit of sulfur power on the surfaces and leave - which is fine in veg. Don't confuse it for powdery mildew (which sulfur also tells to fuck off).

When you think you've defeated them, assume you haven't. They've found some bit of organic shit to eat in a nail/screw/staple hole or crack in something - or they're just hiding there waiting to rebound - so, keep new yellow traps up as an indicator of when/(if) those ones come back. Get those last 'sneaky' ones.
Probably keep spraying the top of soil and planter drain holes with sulfur mix as well.

Make sure it's just wettable sulfur, nothing else in it. It needs to be shaken and mixed well, and shook every...30seconds or so while spraying to keep well in solution.
Something like this, not the one I use, but should be the same: https://www.amazon.com/Bonide-PRODUCTS-142-Sulphur-Fungicide/dp/B0035H7V34/ref=sr_1_2?dchild=1&keywords=wettable+sulfur&qid=1620352172&sr=8-2
Good air movement will also help push the adult fuckers into the yellow traps.
Sometimes I would just stand still in a corner or something and watch where they'd like to land. Or tap a continuously with an object to see if/when they'd come out and where from.

Total dickheads they are.

Edit: I wonder how many spelling errors ^.
 
m4s73r

m4s73r

Well-Known Member
2com said:
Each stage of the critter's life cycle has it's own "length". And each stage requires a different approach, and/or has multiple approaches that may work better or worse than the other, or benefit from using both.
I wouldn't go too overboard with the h2o2 (ie too frequently), depending on strength of mix (don't remember exactly what strength I used.)

But wettable sulfur powder is very cheap and is also something I think is a staple IPM product; everyone should have some.
Yellow sticky traps aren't that expensive. Get a 60 pack of the large ones (maybe...8"x4", can't remember) on amazon and you can cut them in half to get more out of them. They're double sided, too. Peel one side, use it, then cover it and peel the other side. Unless you hang it in "free air" where you can catch the fuckers on both sides. Definitely put some at soil/pot level, lay them on/across the lip or rim of the pot if you can, even with both sides exposed (sticky). The adults are constantly going into the medium to lay more eggs. So you get them coming and leaving.
They are attracted to the color yellow (and other bright colors I think, maybe), and they are attracted to light too. So, put the traps where grow light is hitting them (both below the canopy, like on pot rims, and hanging or placing them on walls or whatever).

Spray wettable sulfur mix (water, sulfur, and some surfactant - peppermint soap works great) on the top of the medium (maybe after water/feeding). Spray the planter drain holes. Spray the entire plant, bottom and top of leaves, and stalk -- but note when this dries it leaves a visual bit of sulfur power on the surfaces and leave - which is fine in veg. Don't confuse it for powdery mildew (which sulfur also tells to fuck off).

When you think you've defeated them, assume you haven't. They've found some bit of organic shit to eat in a nail/screw/staple hole or crack in something - or they're just hiding there waiting to rebound - so, keep new yellow traps up as an indicator of when/(if) those ones come back. Get those last 'sneaky' ones.
Probably keep spraying the top of soil and planter drain holes with sulfur mix as well.

Make sure it's just wettable sulfur, nothing else in it. It needs to be shaken and mixed well, and shook every...30seconds or so while spraying to keep well in solution.
Something like this, not the one I use, but should be the same: https://www.amazon.com/Bonide-PRODUCTS-142-Sulphur-Fungicide/dp/B0035H7V34/ref=sr_1_2?dchild=1&keywords=wettable+sulfur&qid=1620352172&sr=8-2
Good air movement will also help push the adult fuckers into the yellow traps.
Sometimes I would just stand still in a corner or something and watch where they'd like to land. Or tap a continuously with an object to see if/when they'd come out and where from.

Total dickheads they are.

Edit: I wonder how many spelling errors ^.
Click to expand...
or you can increase the soil biology to eat the gnat larvae before it grows wings and flies away... And you do that by mulching and keeping a even moisture level.

or all of all that ^
 
Southernontariogrower

Southernontariogrower

Well-Known Member
jochhe1998 said:
Hey guys,

Have 8 3 gallon plants in coco. Week 4 -5 of flower, synthetic nutes, neem spray once a week for ipm. Had a bit of a fungus gnat problem so I did the standard procedure. Dried out the medium, flushed with hydrogen peroxide, sprayed neem, dried out the medium again, flushed again, sprayed neem again.

Gnats are still present which is usually never the case after that combo.....

My new tactic is to just permanently run hydrogen peroxide in my drip irrigation. My thought is, if the gnat eggs could never hatch because of the peroxide, I won't slow down my plants growth by having to dry out the medium every time. And in two to three weeks all the larger gnats who weren't leaving anyway will be dead.

I tried looking for some info on this before but couldn't find anything. Let me know what you guys think!
Click to expand...
Diamataceous earth topdress thinly or mix as spray, when dry powder like shards of glass to bugs, xtra silica is it is. Can spray for spidermites, dawn blue dishsoap is tension breaker for water, or yucca. Dawn cheaper. Wash off powder buildup after 2 days with fresh water, might take few xs. Doesnt hurt girls at all.
 
J

jochhe1998

Active Member
m4s73r said:
or you can increase the soil biology to eat the gnat larvae before it grows wings and flies away... And you do that by mulching and keeping a even moisture level.

or all of all that ^
Click to expand...
Yeah man, this Is why I love organic no-till so much. It's so much less hassle.

Unfortunately, it's a bit more difficult for high output and commercialization which is why I'm trying out the synthetic runs.
 
J

jochhe1998

Active Member
2com said:
Each stage of the critter's life cycle has it's own "length". And each stage requires a different approach, and/or has multiple approaches that may work better or worse than the other, or benefit from using both.
I wouldn't go too overboard with the h2o2 (ie too frequently), depending on strength of mix (don't remember exactly what strength I used.)

But wettable sulfur powder is very cheap and is also something I think is a staple IPM product; everyone should have some.
Yellow sticky traps aren't that expensive. Get a 60 pack of the large ones (maybe...8"x4", can't remember) on amazon and you can cut them in half to get more out of them. They're double sided, too. Peel one side, use it, then cover it and peel the other side. Unless you hang it in "free air" where you can catch the fuckers on both sides. Definitely put some at soil/pot level, lay them on/across the lip or rim of the pot if you can, even with both sides exposed (sticky). The adults are constantly going into the medium to lay more eggs. So you get them coming and leaving.
They are attracted to the color yellow (and other bright colors I think, maybe), and they are attracted to light too. So, put the traps where grow light is hitting them (both below the canopy, like on pot rims, and hanging or placing them on walls or whatever).

Spray wettable sulfur mix (water, sulfur, and some surfactant - peppermint soap works great) on the top of the medium (maybe after water/feeding). Spray the planter drain holes. Spray the entire plant, bottom and top of leaves, and stalk -- but note when this dries it leaves a visual bit of sulfur power on the surfaces and leave - which is fine in veg. Don't confuse it for powdery mildew (which sulfur also tells to fuck off).

When you think you've defeated them, assume you haven't. They've found some bit of organic shit to eat in a nail/screw/staple hole or crack in something - or they're just hiding there waiting to rebound - so, keep new yellow traps up as an indicator of when/(if) those ones come back. Get those last 'sneaky' ones.
Probably keep spraying the top of soil and planter drain holes with sulfur mix as well.

Make sure it's just wettable sulfur, nothing else in it. It needs to be shaken and mixed well, and shook every...30seconds or so while spraying to keep well in solution.
Something like this, not the one I use, but should be the same: https://www.amazon.com/Bonide-PRODUCTS-142-Sulphur-Fungicide/dp/B0035H7V34/ref=sr_1_2?dchild=1&keywords=wettable+sulfur&qid=1620352172&sr=8-2
Good air movement will also help push the adult fuckers into the yellow traps.
Sometimes I would just stand still in a corner or something and watch where they'd like to land. Or tap a continuously with an object to see if/when they'd come out and where from.

Total dickheads they are.

Edit: I wonder how many spelling errors ^.
Click to expand...
I'll give this a go. Sulfur is hard to come by where I live but I will start to look for it. Would be nice to use it as a dunk every time I re-pot my girls.

Think I'm going to let my medium dry out. Try to catch the majority of the big ones with yellow stickies and apple cider vinegar. Drench the roots with H2O2. Then hit them with hella microbes and BTI. Hopefully, after that, microbiology could help regulate them. I really do not have the time/patience to put up with all of this work much longer.
 
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J

jochhe1998

Active Member
My room is not fully sealed so gnats can fly in as they please. My last run was organic and I had no issues with the gnats - I would let the soil dry out once and they'd be gone.

This is my first 100% synthetic run and it's so difficult to shake them. I'm sure it has to do with this. I run 50/50 coco pearlite and water 3 to 4 times per day usually. Seems to be standard stuff for commercial grows but I'm now starting to wonder if this saturation is rotting my roots and adding to the gnat problem.

I've seen a lot of synthetic coco growers starting to switch to organic liquid nutes as well as adding microbes to their coco runs and perhaps this is one of the reasons why. I'm starting to think synthetic runs are not all that they've cracked up to be. Maybe I just need a properly sealed facility and IPM to really see the difference :p .

I also have a sun-grown grow going outside right now and the difference the sun makes in the pheno's expression is PHENOMENAL. I'm starting to lean towards organic sun-grown no-till for the highest quality buds. All I need now is a climate-controlled greenhouse lol.
 
Wastei

Wastei

Well-Known Member
I would increase airflow across the soil surface. They are very retarded as flyers. I used this technique in combination with yellow/blue sticky traps i in coir. Works really well and should be done for monitoring and staying ahead of an outbreak either way.
 
J

jochhe1998

Active Member
Wastei said:
I would increase airflow across the soil surface. They are very retarded as flyers. I used this technique in combination with yellow/blue sticky traps i in coir. Works really well and should be done for monitoring and staying ahead of an outbreak either way.
Click to expand...
Unfortunately, I already have - no effects. I have a 16-inch fan going straight down all the root zones
 
Southernontariogrower

Southernontariogrower

Well-Known Member
Try topdressing with diamaraceous earth, good silica will kill gnats. Double good. Can be mixed in water as spray but need to rinse, spider mite killer too as spray. Very effective.
 
m4s73r

m4s73r

Well-Known Member
jochhe1998 said:
Yeah man, this Is why I love organic no-till so much. It's so much less hassle.

Unfortunately, it's a bit more difficult for high output and commercialization which is why I'm trying out the synthetic runs.
Click to expand...
Ahh DTW coco set up. TheBucketCompany make s a pretty cool system. If thats what your doing then just a layer of sand over the top of it. If your top watering 3-4 times a day then DE is a waste of time on the top of the coco. And your synthetic could just use H2O2 to kill the larvae off.
 
B

Blazin Budz

Well-Known Member
I'll chime in and mention that gnatrol worked well for me a couple of runs ago. I always have some of the little bastards flying around. They're only really a problem when it becomes an infestation.

I grow in coco which always stays wet. I think next grow, im going to mix crushed up dunks, mosquito bits and gnatrol into my coco before i fill my pots and see if that completely eradicates them.
 
crisnpropa

crisnpropa

Well-Known Member
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2

2com

Well-Known Member
jochhe1998 said:
I would let the soil dry out once and they'd be gone.
Click to expand...
Or, you thought they were gone.
m4s73r said:
If your top watering 3-4 times a day then DE is a waste of time on the top of the coco.
Click to expand...
Yup.

@jochhe1998 One thing I forgot to mention is a physical barrier. That's game over for them, you done have to worry about them entering or leaving the medium at all.
Go search for an informational video/site on fungus gnats, get their average or minimum size in mm, look for a material (synthetic material) that is the right micron (mesh size) to be just enough smaller than the gnats.
When you transplant (eg: from a solo cup to a 1gal, whatever - I don't know what you've got going on) you line the pot with a cut piece of the material/fabric; enough so that when you fill it with medium and put your transplant in and back fill it, that you can bring the "extra" material up and over the top/surface of the medium and up tight to the stalk of the plant. Tie/wrap it around securely. --Yes, you'll need to tie it with a material that will allow stretch as the stalk grows. I can't remember the name of the stuff I used. But if you want, I'll find it. Eg: of fabric would be "row cover", or even some kind of mosquito netting (provided the mesh is small enough).

Everything I've suggested is from personal experience, and all of them work. It's not complicated or difficult just because I gave lengthy "directions". It's easy and pretty cheap.

Note: you said you were using synthetic nutrients in coco. That's why I'm not suggesting various beneficial bacteria/microbes, and other critters, or "health soil biology". Especially when you've been, and want to continue it seems, using h2o2...

You've got tons of suggestions and angles to choose from and now it seems things are getting off the actual topic.

Anyway, hope you can wipe'em out. They're just extremely annoying.
 
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