Fungus Gnats and Air-Pot

[Trimix]

Hi,

So I've got fungus gnats in my grow cabinet. Only a few buzzing about at the minute but I need to nip it in the bud (pardon the pun). I'm growing in an organic soil mix under LED.

Never had to deal with the little sods before but after researching I'm going to give mosquito dunks (bacillus thuringiensis) a go. I gather that I need to disolve the "dunk" in water and then drench the soil, but my question and concern is with the Air-pots.

Unlike traditional pots the gnats have access to the roots much further down due to the air pruning holes so do you guys think I should also spray the pot sides with dunk treated water as well?

I'm also going to put some of the yellow sticky traps out so cross fingers I can irradicate them.

Plants are only a few weeks old so I know I need to act quickly.

Any advice and help greatly appreciated.

Thanks in advance

Trimix

 

[LED Borg]

yeah dude, spray the holes, I had them once during mid flowering in air pots, they were launching out of the sides of mine like gnat torpedo's. lol
I tried most things but the most effective was temps. the lower the better for you and worst for them as they cant breed.
plus theres a product called gnatnix, excellent as a top dressing, too sharp and nasty for gnats, I tried it and it certainly kept my infestation down & I had it bad, they were buzzing around my rooms light and even on my computer screen lol.
live n learn eh? hope it sorts em out for you bro

 

[Corgy]

I had fungus gnats some 6 weeks ago, dusted with Diatomaceous Earth (DE) on the plants and gave a good amount to the topsoil surface and worked it into the top 4-5 cm together with a handful of neem cake more here , and I haven't seen a single insect of any kind from 2 days later. With airpots I would dust the sides too for good measure.......a neat side benefit of DE is that it supplies silicone to the plants as well!

 

[Corgy]

Just saw post #2, and without it says so, it sounds like "too sharp and nasty for gnats" DE.......but let me hazard a guess here, if it is DE, then the addition of the word Gnat has sent 2 liter Gnatnix into the price range of 25 kg DE, or roughly 50 L......

 

[LED Borg]

er but some of us arnt that well informed. lol. I myself had to wiki DE. very interesting but it sounds like its a powder? that gnatnix is like small chunks of white glass, chaffs ya hands up badly if you don't wear gloves.
but I can understand your point, it is pricey and surely could be reproduced cheaper? there ya go, a business op. lol

Diatomaceous earth /ˌdaɪ.ətəˌmeɪʃəs ˈɜːrθ/, also known as D.E., diatomite, or kieselgur/kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white powder. It has a particle size ranging from less than 3 micrometres to more than 1 millimetre, but typically 10 to 200 micrometres. Depending on the granularity, this powder can have an abrasive feel, similar to pumice powder, and has a low density as a result of its high porosity. The typical chemical composition of oven-dried diatomaceous earth is 80 to 90% silica, with 2 to 4% alumina (attributed mostly to clay minerals) and 0.5 to 2% iron oxide.[1]

 

[Corgy]

Yes, it is a powder, very fine like talc. It is readily available on Amazon and eBay. It has been used for donkeys years for cats, dogs, horses and such, and as a human "cleanser" when sold as such at 50 times the price as plain vanilla Kiselgur which is just the same, much like bentonite or montmorillonite clay.

If it is applied when the soil, or medium(I use it with Mapito too), is wet and left for a couple of days before the next watering, it forms a crust on the surface of the topsoil that allows water to pass through but it stays more or less intact if watering is done slowly and gently. In my autopots this is not an issue with bottom watering, with airpots it's the way to do.

Here a 2 day old pic of an airpot that was dusted when the HBSS went into the soil some 10 days ago. The whit-ish crust is the DE....

 

[LED Borg]

that is so cool bro! genius knowledge. thanks for sharing that superb info and your plants look fantastic!

 

[Waira]

Tri'-- IMO, the dunks are the best option, because when watered in, it'll penetrate all the way down to the bottom; it's the larvae that are the root munchers, and they will be dispersed all over in the soil,... air pots make this worse because of access and better O2 penetration; adults are little more than flying gonads! Diatomaceous earth comes from the "shells" of single cell algae, that build them in an amazing array of shapes and complex geometry,... they deposit on sea floors and become a form of sedimentary rock basically; at the microscopic level, they're like glass shards and spikes, that pierce and slice into tender sections on bugs, causing them to bleed out, simply put! problem is, as a fine powder, it won't penetrate deeply enough to nail the more buried larvae, though, like Corgy says, as a surface/shallow depth protection, it's great! If you can, look for the granular type 'squito dunks, easier to use; Bonide makes a good one, comes in several little packets...got mine at OSH; otherwise, crumble the dunk up real well to make 1 couple tablespoon's worth of material (based on1gal water)--> Now, to wake the bacteria up and boost population numbers rapidly, here's a 'recipe" based on 1 gal of clean, dechlorinated water: take 1/2 a packet and toss into bucket; add 2T molasses and a dash of nute's and mix in (dissolve the molasses in warm water first for faster dilution); if you have some wetting agent/water spreader, or a very mild soap, put 1/2tsp in there too, to help saturate the granules faster,... stir well, add some air bubbling if you can, and let it sit for a day or so, mixing up a few times,... then just water as usual, but no need to totally drench it, the bacteria will disperse some as well, and further watering will help; be sure to resuspend the granules as you do.... I find that this will last for most of the grow,... reapply as needed!

 

[BRICH999]

DE is amazing stuff and completely eradicated my fungus gnat issue. I mix in a cup per pot into the soil and sprinkle more on the surface. I also reapply halfway thru grow when im most likely to see gnats. Still have the yellow stickies around, but the only thing thats been stuck to them recently has been me (couple times)

 

[Corgy]

Tri'-- IMO, the dunks are the best option, because when watered in, it'll penetrate all the way down to the bottom; it's the larvae that are the root munchers, and they will be dispersed all over in the soil,... air pots make this worse because of access and better O2 penetration; adults are little more than flying gonads! Diatomaceous earth comes from the "shells" of single cell algae, that build them in an amazing array of shapes and complex geometry,... they deposit on sea floors and become a form of sedimentary rock basically; at the microscopic level, they're like glass shards and spikes, that pierce and slice into tender sections on bugs, causing them to bleed out, simply put! problem is, as a fine powder, it won't penetrate deeply enough to nail the more buried larvae, though, like Corgy says, as a surface/shallow depth protection, it's great! If you can, look for the granular type 'squito dunks, easier to use; Bonide makes a good one, comes in several little packets...got mine at OSH; otherwise, crumble the dunk up real well to make 1 couple tablespoon's worth of material (based on1gal water)--> Now, to wake the bacteria up and boost population numbers rapidly, here's a 'recipe" based on 1 gal of clean, dechlorinated water: take 1/2 a packet and toss into bucket; add 2T molasses and a dash of nute's and mix in (dissolve the molasses in warm water first for faster dilution); if you have some wetting agent/water spreader, or a very mild soap, put 1/2tsp in there too, to help saturate the granules faster,... stir well, add some air bubbling if you can, and let it sit for a day or so, mixing up a few times,... then just water as usual, but no need to totally drench it, the bacteria will disperse some as well, and further watering will help; be sure to resuspend the granules as you do.... I find that this will last for most of the grow,... reapply as needed!

Yes, I think you're right about the dunks being the best solution in this situation with an already infested Airpot. Does anyone know if these "dunks" are available in some form being named what in Europe?

If I had the dunks, I would brew up a mix and for good measure add some DE for a double whammy with no compatibility nor toxic issues. I have no doubt that the DE will penetrate the entire soil when suspended in water due to their size, less than 40 micron.
Prevention is better than firefighting, so for me, DE and not forgetting neem cake, is standard additives I add to any medium as a matter of course and it only takes a minute to do, mixed into the soil and a top layer as a barrier. Both are cheap, cheerful and organic, and together they provide combined contact and chemical systemic defense/eradication with no resistance build-up plus both also provide nutrition and trace minerals...... And to top it all off, the DE also acts as a dessicant........What's not to like.......why is everybody not doing this?