Are fungus gnats "bad" if not eating your plants?

[softyellowlight]

I'm continuing my 1000W 4x4' garden of air pots and seeing a rise of fungus gnats. I believe they're actually gnats because they don't behave like aphids or flies but look somewhat like flies, and they seem to only care about the dirt. Because I have Blumat auto-waterers dripping, I have beautiful translucent roots growing up to the very surface in areas, and the insects don't even give a fuck about that.

So should I worry about these suckers at all? I always played with insects and other small creatures when I was little so they don't gross me out, so if there's no real harm, maybe I should let them be instead of trying to do anything about them. I do have some surface fungus on the soil, though not much. What do you guys think?

 

[itisme]

Yes. They will cause issues. You need to treat for them. I recommend azamax.

 

[Brother Bear]

I have come to accept fungus gnats as part of growing. At least for myself anyhow. Long as there are only a few buzzing around i don't bother with them. But if they start multiplying then i hang a few fly strips and start watering from the bottom till they diminish again.

 

[medleaf]

I recommend nematodes. or BT, which you can get as mosquito dunks or mosquito bits. But the best control is nematodes. peace leaf

 

[chase]

Let your soil dry out a little more in between waterings.

 

[medleaf]

or put a slice of potato on top of the soil each night then throw it away each morning. The high starch will cause the adults to lay their eggs in the potato this is only a moderate form of control. peace leaf

 

[Brother Bear]

Let your soil dry out a little more in between waterings.

Not gonna work while using blumats.

or put a slice of potato on top of the soil each night then throw it away each morning. The high starch will cause the adults to lay their eggs in the potato this is only a moderate form of control. peace leaf

Good idea.
They will also fly into and die in a bit of OJ in a cup

 

[pinecone]

So should I worry about these suckers at all? I always played with insects and other small creatures when I was little so they don't gross me out, so if there's no real harm, maybe I should let them be instead of trying to do anything about them. I do have some surface fungus on the soil, though not much. What do you guys think?

I wouldn't worry about it.

There are a continuum of schools of thoughts with respect to bugs. At one end of the continuum there are growers don't want to tolerate any bug and will go to any length to eliminate anything that moves in their grow. On the other end of the spectrum you have growers that welcome nearly any bug with the idea that "pest" will be controlled through predation or through periodic use of a non-systemic, natural pesticide (neem, lavender, soap and water).

Pine

 

[Sam the Caveman]

Personally, I would get rid of them. The larvae do munch on the roots of the plants.

You could try a multi-prong approach if you want to do organic remedies. Put a layer of sand on top of the pot, this will keep the adults from laying eggs there. Also water with a mosquito dunk tea, molassas water+mosquito dunk+airstone+24hrs.

Or if you plants are not too far into flowering, just use some imid.

 

[softyellowlight]

Okay, so what if I say that I would be tolerant of some but I think they're getting to a population level I don't really enjoy to see buzzing around, and I don't care about removing them completely but reducing their levels would be fine. I notice no one has mentioned diatomaceous earth. I prefer to use the simplest and most organic solutions possible, so would that affect their cycle drastically, do you think?

My babies are just expressing their true bud structure now, a few weeks into 12/12 with parents that flowered mostly around one month (male) and almost two and a half months (female, later as sins). I would therefore prefer not to insert anything into the soil or onto the leaves at this point, not for a truly scientific reason, but simply because that skeezes me out more than a handful of not-very-harmful insects.

 

[joe fresh]

Fungus Gnat


An adult fungus gnat

Fungus gnat as a maggot

Prevent: Do not overwater, keep the relative humidity of your garden low, do not let the surface of your grow medium stay soggy. Cover hydroponic medium surfaces to prevent growth of green algae.
Identify: Fungus gnats attack your plant in their adult stage and larval stage. The maggot of the fungus gnat is almost invisible to the human eye with see-through bodies and a black head. These maggots infest the upper roots of your plants and can spread throughout the entire root system in hydroponic mediums. Maggots love dark, dank, moist, soaked environments. Check the medium at the base of your plant for these pests, fungus gnat larvae are notoriously happy in rockwool. These creatures infest root systems, damaging larger roots and consuming root hairs. This causes your plant to weaken, slow its growth, and fading in the foliage. These wounds to the roots make marijuana insanely vulnerable to several types of fungus. Maggots love dying plant matter and will only infest more heavily the more damaged your plant becomes. Adult gnats are grey to black, very small and have very very long legs. Females lay eggs prolifically at the rate of 200 eggs weekly and will usually be found at the base of your plant along with maggots. Additionally, these little pests will stick to your sticky flowering green like crazy and are basically impossible to remove.

Fungus gnats have successfully damaged the root system of this plant. Note the yellowing leaves and the two plants leaning over as their root systems are beginning to rot.

Eradicate
Repression: Reducing surface moisture in your plants medium will slow fungus gnats reproductive cycle dramatically, the drier the better. Applying an anti-algae product around the bases of your plant will kill any growing green algae and reduce the food sources of growing maggots. Yellow sticky traps placed 2 inches from the base of your medium will snag a good chunk of departing adults.
Predators: Introducing a predator for the gnats themselves has proved ineffective at eliminating a population. The predatory soil mite Hypoaspis and nematode Steinemema feltiae will severely impact the insect population if introduced to soil grows. These creatures will not be effective countermeasures in hydroponic application.
Manual Removal: Impossible. You can swat a few but your threat is from what has already been laid underground.
Spray: Neem or insecticidal soap applied as a soil drench will kill eggs and larvae present in 1-3 applications. Any pesticide spray containing the fungal culture Bacillus thuringiensis var. israelensis (Bt-i) will successfully eradicate adult gnats. Apply soil drenches and spray simultaneously every 5-10 days.




now i have gnats and let me tell you they do some hella damage when not looked after and taken care of...my plants look similar top the ones in the pic i posted....gonna treat them with azamaz, bti, or neem.....

 

[softyellowlight]

I do also wonder, could a small amount even be symbiotically beneficial if I have a small amount of surface fungus thanks to the Blumats' constant dripping and the composition of my soil? How far down do the grubs go when they attempt to eat roots? I think eating surface fungus might result in less fungal spores flying around, right?

 

[joe fresh]

nope...fungus gnats eat at healthy roots as well as rotting one, when they eat the healthy roots they can introduce pathogens and bad bacteria into the roots and root zone...there is nothing beneficial about gnats

 

[mad librettist]

a single nematode application can keep their numbers very low for 18 months...

 

[softyellowlight]

joe, that looks like them, yeah. They're mostly in the pots that do not have weed growing in them, as I cut off the tops of the old plants and planted other stuff in them. Are those old roots then the breeding ground that I need to get rid of? I already have neem oil, and I'd feel comfortable watering that in regularly.

 

[Sam the Caveman]

Okay, so what if I say that I would be tolerant of some but I think they're getting to a population level I don't really enjoy to see buzzing around, and I don't care about removing them completely but reducing their levels would be fine. I notice no one has mentioned diatomaceous earth. I prefer to use the simplest and most organic solutions possible, so would that affect their cycle drastically, do you think?

I mix diatomaceous earth into my soil and I still get population explosions of fungus gnats. I mix de at a rate of 1.5 tbl/g of soil.

 

[Herborizer]

I have seen fungus gnats cause problems. I don't like them at all. Here is the solution I am doing: https://www.icmag.com/ic/showthread.php?t=227443

 

[softyellowlight]

a single nematode application can keep their numbers very low for 18 months...

Would you recommend a particular brand or vendor? That sounds like exactly my kind of fix, simple and organic or symbiotic.

 

[Brother Bear]

I mix diatomaceous earth into my soil and I still get population explosions of fungus gnats. I mix de at a rate of 1.5 tbl/g of soil.

I believe it is supposed to be covering the top when used to combat fungus gnats, not mixed in. Supposed to cut the exoskeleton that way yeah ?

 

[DGSIX]

I've heard they can't burrow more than 2 or 3 inches. I could be mistaken though. I use yellow sticky traps and a little neem to keep em situated. When you are working with organics, you just get them. I don't know if all them do, but soil companies just leave their soil outside in a pile. I once found a rather large spider in my tent that was definately not from the midwest, nor could it have gotten into my sealed system.