Fungus Gnats for days!

[roasthawg]

Ok, I have a serious gnat problem and am trying to figure out the best plan of attack. I'm in coco and the problem stems from me watering til runoff every day. The coco stays wet hence the gnats. I'm currently finishing up week three of using Microbelift BMC at 1mil/gal with every watering and while I think it might be cutting the population back some I wouldn't swear to it and it definitely has not killed them all off (by the way, these are definitely fungus gnats and NOT root aphids). Does BTI take longer than 3 weeks to work?

I've also just started adding nematodes and have some hypoasis miles coming in the mail. I've tried predators before with no luck but I think it might take more of them or maybe just consistent useage.

I also have a packet of azasol that I haven't tried yet... not sure if it'll kill the nematodes/hypoasis as well as gnats.

Anything I'm missing? Any ideas?? Can't stand these things.... maggots for days in my soil and dead gnats all over my flowers!!

 

[BOMBAYCAT]

When I get gnats I tend to use the mosquito dunks (has BTI remains in it) you buy at Lowes or Home Depot. You need to scrape off a quarter teaspoon and sprinkle it on top of the pot and close to the holes where the runoff is. I have used the yellow colored sticky traps but the gnats outnumbered the traps. I have never tried but some growers swear by the fine steel wool. They stretch it out so it covers the top of the pot and the little bastards get shredded as they come out of the pot. Some people like an inch of Diatomaceous earth on top as it also shreds them. I have even heard of people using a layer of sand. My black cat chases them all day but I guess that is not pest control.

 

[BOMBAYCAT]

The mosquito dunks take a couple weeks to work and will also kill the nemotodes probably.

 

[roasthawg]

When I get gnats I tend to use the mosquito dunks (has BTI remains in it) you buy at Lowes or Home Depot. You need to scrape off a quarter teaspoon and sprinkle it on top of the pot and close to the holes where the runoff is. I have used the yellow colored sticky traps but the gnats outnumbered the traps. I have never tried but some growers swear by the fine steel wool. They stretch it out so it covers the top of the pot and the little bastards get shredded as they come out of the pot. Some people like an inch of Diatomaceous earth on top as it also shreds them. I have even heard of people using a layer of sand. My black cat chases them all day but I guess that is not pest control.

Thanks for the reply... I've done the dunks before as well. I'm using Microbelift BMC right now which supposedly has a lot more bti than the dunks do. It hasn't made much of a dent in the population so far as I can tell after three weeks usage... maybe it takes more time?

 

[BOMBAYCAT]

BTI interupts their life cycle and they gradually die off and go away. I am thinking you should see the numbers get less over time and in a couple weeks no more gnats. I have heard some people say gnats don't matter and others say they hurt the plants by eating roots and letting in disease. Anyway they are a pain. I've always seen them fade away after a couple weeks so I am wondering if you have seen any difference by now?

 

[bigbag]

heard sprinkling cinnamon, top dress works well...

 

[roasthawg]

BTI interupts their life cycle and they gradually die off and go away. I am thinking you should see the numbers get less over time and in a couple weeks no more gnats. I have heard some people say gnats don't matter and others say they hurt the plants by eating roots and letting in disease. Anyway they are a pain. I've always seen them fade away after a couple weeks so I am wondering if you have seen any difference by now?

It's hard to say if I've noticed a difference or not yet... I'd like to think I have but I may be tricking myself as well. I have a pretty bad infestation. Regardless of any possible root damage the larvae might be doing I've had to throw away top colas due to them being covered with dead fliers. Gross and irritating.

 

[siftedunity]

to be honest the best treatment for fungus gnats is those sticky label catcher things that you can stick in the soil. I put about 4 per pot and the numbers drop considerably. I think catching the adults prevents them breeding. ive tried chemicals but none of them are as good as sticky traps unless you use more powerful insecticides and tbh they are unnecessary really.

 

[roasthawg]

to be honest the best treatment for fungus gnats is those sticky label catcher things that you can stick in the soil. I put about 4 per pot and the numbers drop considerably. I think catching the adults prevents them breeding. ive tried chemicals but none of them are as good as sticky traps unless you use more powerful insecticides and tbh they are unnecessary really.

I got sticky traps... four per 8x4 table. Maybe I need more as they fill up pretty quickly.

 

[Dynamite]

i grow in rockwool ~ notorious for gnats .. been growing in wool for 20yrs

there is only ONE sure fire product on the market that works and will not harm your plant in any fashion for getting rid of gnats (works just as good in coco)

Gnatrol .. it's a power , mosquito dunk are basically the same , but when you use dunks your using an un-metered amount .. get some Gnatrol power , and follow the instructions for "mild infestation" , make sure the water your using in non-chlorinated , problem solved ..works every time

 

[ozzieAI]

drenching with pure neem oil worked for me...adding neem cake stopped them from ever returning...

good luck

 

[RB56]

Second on the Gnatrol. The BTI you're using must be dead. It kills the larvae so you need to use it every few days for a few weeks to stop an infestation. No way you could be treating every day for 3 weeks with active BTI without results.

 

[roasthawg]

Second on the Gnatrol. The BTI you're using must be dead. It kills the larvae so you need to use it every few days for a few weeks to stop an infestation. No way you could be treating every day for 3 weeks with active BTI without results.

Ok, this is useful information. Maybe I have a bad bunch of Microbelift? I do use ogbiowar tea once a week and it has bti in it too... but I'll order some gnatrol and replace the bti with that.

 

[roasthawg]

i grow in rockwool ~ notorious for gnats .. been growing in wool for 20yrs

there is only ONE sure fire product on the market that works and will not harm your plant in any fashion for getting rid of gnats (works just as good in coco)

Gnatrol .. it's a power , mosquito dunk are basically the same , but when you use dunks your using an un-metered amount .. get some Gnatrol power , and follow the instructions for "mild infestation" , make sure the water your using in non-chlorinated , problem solved ..works every time

Yeah I've been using Microbelift BMC (active ingredient is bti) with not much luck. Maybe a bad or old batch?

 

[roasthawg]

What's the dosage and usage rate on gnatrol? I'm in coco and I water three 4x8 trays with 20gal/day.

 

[The OrigF/clred]

my bud's grow had a bad gnat infestation that came in with some foxfarm happy frog soil. The mosquito dunks never totally eradicated them - maybe knocked them down 70% (this was in a soil grow).

tried DE from Safer Brand and put it on the soil, about 3/4" layer - it just solidified the first time he watered the plants -

he ended up taking it out of the pots, then he tried steel wool (#0000) and that didn't do it either

but the interesting part - he'd placed some in the run-off trays and on the table around the pots, ie just a heavy dusting, as he'd seen them running under the run-off trays. Damn if the population didn't go down fairly quickly - in about 2 weeks they were down to only seeing one or two every few days and after that, maybe one every week or two. Yesterday i saw the first one in about two weeks (he still has two open bags of the Happy Frog soil in his veg room - suspect they're still hatching out of those). I'm over there most everyday btw, helping him and learning as i go

did some research on the Safer Brand and noticed they sell it for a number of pests (cockroaches etc) and indicate they have a "bait" in it to attract pests.

all i know is when he first put it down on the tables you could see them fly to it (sometimes at the last minute they'll fly away) but most of the time they'd land - you'll also see them walk into it, and that was it. The dust is also somewhat yellowish, so that may help attract them as well, all i know i won't be using that DE on the soil for my grow - but will be on the tables

FWIW - hope it helps

 

[roasthawg]

my bud's grow had a bad gnat infestation that came in with some foxfarm happy frog soil. The mosquito dunks never totally eradicated them - maybe knocked them down 70% (this was in a soil grow).

tried DE from Safer Brand and put it on the soil, about 3/4" layer - it just solidified the first time he watered the plants -

he ended up taking it out of the pots, then he tried steel wool (#0000) and that didn't do it either

but the interesting part - he'd placed some in the run-off trays and on the table around the pots, ie just a heavy dusting, as he'd seen them running under the run-off trays. Damn if the population didn't go down fairly quickly - in about 2 weeks they were down to only seeing one or two every few days and after that, maybe one every week or two. Yesterday i saw the first one in about two weeks (he still has two open bags of the Happy Frog soil in his veg room - suspect they're still hatching out of those). I'm over there most everyday btw, helping him and learning as i go

did some research on the Safer Brand and noticed they sell it for a number of pests (cockroaches etc) and indicate they have a "bait" in it to attract pests.

all i know is when he first put it down on the tables you could see them fly to it (sometimes at the last minute they'll fly away) but most of the time they'd land - you'll also see them walk into it, and that was it. The dust is also somewhat yellowish, so that may help attract them as well, all i know i won't be using that DE on the soil for my grow - but will be on the tables

FWIW - hope it helps

Interesting. Dunno how I could incorporate that into my setup as I'm in 4x8 coco beds and the runoff drains outside of the room but definitely good information regardless! Appreciate the take on the DE drying on top of the soil as I haven't tried that route yet but WAS something I was contemplating.

 

[roasthawg]

Was just thinking that many people recommend not running compost tea thru an impeller pump... you guys that are using gnatrol/bti with success are you mixing your res with an impeller pump? I normally mix my res for 15min or so with a pump before using the pump to water... could that be killing a lot of the bti??

 

[Hash Zeppelin]

Second on the Gnatrol. The BTI you're using must be dead. It kills the larvae so you need to use it every few days for a few weeks to stop an infestation. No way you could be treating every day for 3 weeks with active BTI without results.

I third the gnatrol. works for me every time.

 

[Tonygreen]

I soak some of them dunks in gallons of water overnight or longer and use it for a week or two and it works every time. Takes like a week to ten days and they will be gone. You can also crush em up and sprinkle the dust on top yer soil.