|
MycoMykey
Stranger


Registered: 11/30/17
Posts: 51
Last seen: 2 years, 5 months
|
FUNGUS GNATS!! Need help big time 1
#26375244 - 12/11/19 03:02 PM (4 years, 2 months ago) |
|
|
I currently work as a cannabis grower for a company in Pennsylvania. We have a really bad fungus gnat problem that we cant seem to get under control. With the regulations we cant even use Hydrogen peroxide on the plants to get rid of them. We have Large grow rooms with about 800 plants in each. We grow hydroponically in coco coir cubes. Does anyone have an effective solution to getting rid of these pests on this big of a scale without the use of pesticides? We have tried sticky traps and have tried covering the tops of the medium with perlite but has not had much of an effect. We are pretty sure that the cubes are contaminated with the fungus gnats when we receive them. We have thought about pasteurizing the cubes but on this big of a scale that would take too much time to get done. Also we have thought of soaking the cubes in peroxide before the plants are put into them but that would also take too much time. We can't really use any pesticides so we are trying to think outside the box a little to get rid of them. Anyone else have this problem that could help? We are trying predatory nematodes right now hopefully those will help
Edited by MycoMykey (12/11/19 03:45 PM)
|
Hobbit GDF
Deadhead



Registered: 02/14/19
Posts: 3,406
Loc: Terrapin station
|
Re: FUNGUS GNATS!! Need help big time [Re: MycoMykey]
#26375333 - 12/11/19 03:39 PM (4 years, 2 months ago) |
|
|
They f****** suck I have them in my tent I hope you guys get rid of them good luck I'm not sure how to do it
|
MycoMykey
Stranger


Registered: 11/30/17
Posts: 51
Last seen: 2 years, 5 months
|
Re: FUNGUS GNATS!! Need help big time [Re: Hobbit GDF]
#26375352 - 12/11/19 03:46 PM (4 years, 2 months ago) |
|
|
we are trying predatory nematodes in the water tanks right now so hopefully that will get rid of them.
|
Shr00mEater
Strange

Registered: 10/17/18
Posts: 985
|
Re: FUNGUS GNATS!! Need help big time [Re: MycoMykey]
#26375503 - 12/11/19 04:37 PM (4 years, 2 months ago) |
|
|
Read your other post about the mold too.....
Yuck. It sounds like the whole grow op is fucked.
Nematodes are a good idea. Azamax and b.t. Are also some things too look at. They are most likely coming in on the coir. Saying it takes too much time to pasteurize the medium sounds a lot like bullshit. I mean, think of what kind of time and money you guys are going to waste trying to deal with these issues now. I bet any wasted time on the front end of a grow is negligible compared to ending up with shit results at the end.
A big key to prevent a large outbreak is to keep moisture levels reduced. Are you letting the medium dry out a big between waterings? They only lay eggs in the top few inches.
The perlite on top was a bad idea. That will prevent the top few inches from drying out, the moist condition is perfect for incubating baby flies.
|
Solipsis
m̶a̶d̶ disappointed scientist



Registered: 12/28/09
Posts: 3,398
Loc: the Neitherlands
Last seen: 6 months, 6 days
|
Re: FUNGUS GNATS!! Need help big time [Re: Shr00mEater]
#26376466 - 12/12/19 03:10 AM (4 years, 2 months ago) |
|
|
Sand is better on top of soil, but it can wash into the soil over time which isnt good for the roots.. and also it doesnt fix the problem but just helps partially.
I'm now going to experiment with Metarhizium as another biological pesticide. I hear great things but also that it might "cause" resistance or that some insects are resistant to it. Honestly i find it hard anyway to keep track of what species it can or cant kill. Also look up the laws and regulations on that stuff.. I also heard it can be expensive, even though it doesnt seem hard to produce.
For the resistance it may be best to combine with another effective treatment to make the odds very small of double resistance.
Bti has seemed to help for me before too, although it primarily works on a certain larval stage and is not stable in moist soil. No idea how stable the mold is or how long it lasts but I think it may just spread itself pretty well.
|
hummingbird

Registered: 06/29/14
Posts: 2,134
|
Re: FUNGUS GNATS!! Need help big time [Re: Solipsis] 1
#26376483 - 12/12/19 03:31 AM (4 years, 2 months ago) |
|
|
Can you use b.t.i? If so, some mosquito dunks or gnatrol in the water tanks would kill the larva. Keep the yellow sticky traps up to catch the adults too.
|
Sugabearcrisp
Not Your Average Bear



Registered: 10/14/19
Posts: 12,135
Loc: maybe I had too much, too fast
Last seen: 57 minutes, 28 seconds
|
Re: FUNGUS GNATS!! Need help big time [Re: hummingbird] 1
#26376509 - 12/12/19 04:27 AM (4 years, 2 months ago) |
|
|
Have you tried setting up fans moving air around under the canopy, at the soil/medium level. People often forget to provide for adequate air movement below the canopy which can result in fungus issues like stem rot, mold and fungus gnats. A few fans keeping a steady breeze at this level will keep the surface of your medium dry and make it hard for the gnats to fly around and land to lay eggs.
You say you are growing hydroponically but it sounds more like drain to waste coco coir. Otherwise I would cover the tops completely with foil sided foam board.
|
Digit
Surreal Estate Agent
Registered: 08/10/15
Posts: 69
Loc: tierra incognita
|
Re: FUNGUS GNATS!! Need help big time [Re: Sugabearcrisp]
#26380063 - 12/13/19 07:41 PM (4 years, 2 months ago) |
|
|
BT works pretty well, if you're allowed to use it. It's a naturally occurring bacteria that is only toxic to insect larvae. It's commonly found in a product called "mosquito dunks", which are intended to be used in ponds to prevent mosquitoes from breeding in the stagnant water. I just crumble them and spread them on top of the soil, or if you have a reservoir for your nute solution you could just throw them in there and let them soak for a while before you water the plants. It probably won't completely eliminate the problem but it can seriously knock it down. I suspect you can also find BT in a liquid form if you look around. It takes a little while to notice it working because it doesn't kill the adult flies, but it stops them from breeding in your soil, or whatever medium you're using. The flies themselves are not harmful to plants but the larvae can eat the roots and cause some damage, although I've mainly found fungus gnats to more of an annoyance than a serious pest.
Best wishes
Edited by Digit (12/13/19 07:45 PM)
|
Raven44
Entry not permitted to muggles


Registered: 12/07/13
Posts: 1,970
Loc: My sovereign reality bubble
|
Re: FUNGUS GNATS!! Need help big time [Re: Digit] 1
#26380110 - 12/13/19 08:16 PM (4 years, 2 months ago) |
|
|
Let plants dry out on top by bottom watering for a few weeks
Raid strips the blue ones that you hang up with a thumb tack and are sticky fly paper ten in a pack or so maybe 12. Super cheap and effective
Edited by Raven44 (12/13/19 08:17 PM)
|
hummingbird

Registered: 06/29/14
Posts: 2,134
|
Re: FUNGUS GNATS!! Need help big time [Re: Raven44]
#26381774 - 12/14/19 05:33 PM (4 years, 2 months ago) |
|
|
Fungus gnats like the yellow color ones. I like to use yellow duct tape pieces with a product called tanglefoot smeared on them...waay cheaper than the premade ones, and you can stick them on the edge of the pots or wherever you want.
|
freerange
Passing Thru



Registered: 11/14/19
Posts: 27
Loc: OREGON
Last seen: 4 years, 1 month
|
Re: FUNGUS GNATS!! Need help big time [Re: hummingbird]
#26384079 - 12/15/19 08:17 PM (4 years, 2 months ago) |
|
|
Pyganic
|
Raven44
Entry not permitted to muggles


Registered: 12/07/13
Posts: 1,970
Loc: My sovereign reality bubble
|
Re: FUNGUS GNATS!! Need help big time [Re: hummingbird]
#26384096 - 12/15/19 08:35 PM (4 years, 2 months ago) |
|
|
Yeah those don’t work nearly as good as the raid one you hang. And the sticky part isn’t blue only the package is
Those cards you lay on top of the soil or wherever suck ime compared to what I’m talking about
|
Phantom45
Traveler


Registered: 06/08/19
Posts: 188
|
Re: FUNGUS GNATS!! Need help big time [Re: Raven44] 1
#26384157 - 12/15/19 09:07 PM (4 years, 2 months ago) |
|
|
How about diatomaceous earth ive used it and had success
|
Solipsis
m̶a̶d̶ disappointed scientist



Registered: 12/28/09
Posts: 3,398
Loc: the Neitherlands
Last seen: 6 months, 6 days
|
Re: FUNGUS GNATS!! Need help big time [Re: Phantom45] 1
#26384814 - 12/16/19 10:12 AM (4 years, 2 months ago) |
|
|
DE deters them but i hear breaks down and washes into soil - like sharp sand which i use myself to top various soils (combined with decorative stones and pebbles etc) it makes it suck for them a bit to go through. But if you are beyond a certain epidemic point i think you better get more aggressive and try to get them at multiple stages of their life cycle to break the 'spell'.
Like pyrethrins work quite well i'd say (for once every season max tho), but work on contact and i think not to much on eggs which they find places to stow away, crafty basterds.
I've wondered if regular basic insecticidal soap (which i generally love and always keep around to keep adults under control) is bad to really get into your soil, like if it affects the nutrition in the soil. That could be refertilized but idk if its a bad plan for other reasons. I do it sometimes with particular temporary plant containers.
My general tip is try smart combo's for more than one life stage, of treatments which kill and not just deter. For me that works well. Also step in in time and use the deterrants as prevention. It's easier to control than exterminate imo.
|
The Mycologist
Explorer

Registered: 05/06/16
Posts: 3,024
Last seen: 13 days, 21 hours
|
Re: FUNGUS GNATS!! Need help big time [Re: Solipsis]
#26384857 - 12/16/19 10:32 AM (4 years, 2 months ago) |
|
|
I have seen bug zappers that suck the bugs in.
-------------------- "That you are here—that life exists, and identity; That the powerful play goes on, and you will contribute a verse.” ― Walt Whitman, Leaves of Grass

|
Jooby
Stranger



Registered: 11/13/19
Posts: 174
Last seen: 2 years, 2 months
|
|
I use Food Grade DE and sticky traps. Works every single time. Granted, I use soiless and 25 plants.
|
Phantom45
Traveler


Registered: 06/08/19
Posts: 188
|
Re: FUNGUS GNATS!! Need help big time [Re: Jooby]
#26385982 - 12/16/19 08:36 PM (4 years, 2 months ago) |
|
|
Ya all i know is i used it on my coco and it worked for me
|
Solipsis
m̶a̶d̶ disappointed scientist



Registered: 12/28/09
Posts: 3,398
Loc: the Neitherlands
Last seen: 6 months, 6 days
|
Re: FUNGUS GNATS!! Need help big time [Re: Phantom45]
#26388436 - 12/18/19 10:00 AM (4 years, 1 month ago) |
|
|
I figure the gnats are much worse on actual soil than soilless / coir, as soil has decayable materials which will rot if too wet and this attracts gnats to lay a lot of eggs in. It's the fungi etc that make the smells that attract them.
|
myrealname
Stranger

Registered: 05/22/07
Posts: 2,757
|
Re: FUNGUS GNATS!! Need help big time [Re: MycoMykey]
#26390038 - 12/19/19 04:30 AM (4 years, 1 month ago) |
|
|
h202 is the only thing Ive heard of working. Add it to the nutrient solution each time from start to finish.
Yellow sticky traps everywhere to start catching any adults also.
|
freerange
Passing Thru



Registered: 11/14/19
Posts: 27
Loc: OREGON
Last seen: 4 years, 1 month
|
Re: FUNGUS GNATS!! Need help big time [Re: myrealname]
#26391021 - 12/19/19 04:46 PM (4 years, 1 month ago) |
|
|
You can also plug your drip holes before planting with roockwool and then add a layer of neem meal to the top of your medium. That and the pyganic drench has killed them off many many times in my med garden.
Edited by freerange (12/19/19 04:47 PM)
|
|