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Help with these gnats!!

Teaks

Teaks

Hey everyone, I'm having a serious gnat problem. I've got about 60 seedlings, 3 full grown peppers all in about 2/3 coco and 1/3 perlite, and a tomato in about a 6 gallon pot of soil.

The tomato has been a constant spawn of fungus gnats but they've been.. tolerable. However, I am now having some real issues with them. For instance, one of my maybe month old plant was not growing at all and the leaves were looking really bad. So I thought I've had good luck reviving plants by putting them in net cups and having them stay hydro style.

That's when I began removing the soil and container and saw how infested the medium was with little tiny white larvae, about the thickness of roots. Which is what I I they were until they started squirming.

I've tried the vinegar traps, water traps, sticky traps.. nothing is working and I cannot just ignore the problem anymore or I will probably lose all of these seedlings.

Can anyone recommend a no sh*t method of exterminating these pesky gnats? Are there any products I can get in store that will kill off the infestation and won't kill my seedlings?

I've been tempted to try dusting everything in the Seven dust because I've used it on outside gardens but it was midway through growing season sothe plants could tolerate it.


I need something strong that's going to wipe out the lot and I would really appreciate I help you guys could offer. Any searches i do just gives the same old vinegar in a jar trick but I'm beyond that.

Thanks in advance, I'd like to really have something to apply to the issue by tomorrow.
 
juanitos said:
yup i've used mosquito bits, very effective. not an instant solution though, takes a week or so to kill all the larvae.
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I've got some ordered, reviews seemed positive. I just wonder if it will effect seedlings
 
If you suspect you have a fungus gnat problem, the quickest way to find it is to half-bury a 1-inch cube of raw potato in your potting soil overnight. By morning all those larvae will be cozied up next to the piece of potato, and will be very easy to spot when you remove it.
 
stickman said:
If you suspect you have a fungus gnat problem, the quickest way to find it is to half-bury a 1-inch cube of raw potato in your potting soil overnight. By morning all those larvae will be cozied up next to the piece of potato, and will be very easy to spot when you remove it.
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Thanks for the tip! I'm actually pretty sure that's what they are now that I've seen another adult flying around the seedlings and my tomatoes have a little bit of damage on their true leaves. Haven't checked cotys.
 
In my experience, there is only one way to rid yourself of the gnats for good. You have to go full nuclear. Remove all unnecessary soil from the grow area. Treat every plant in the whole house with a systemic insecticide and put up way too many sticky traps. It only takes one survivor to reinfect the plants without a systemic.
If you just need to make it through till spring plant out without your plants dying, then I would recommend hydrogen peroxide treatments. It will kill your fungus gnat larvae on contact.
This link has some useful information
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/using-hydrogen-peroxide-in-garden.htm

Good luck
 
From what I understand, fungus gnats are there because there is food attracting them. By food, I mean perfect conditions such has water logged soil that create fungus & rotten roots.
 
Reset the soil with H2O2 then maybe keep the soil humidity lower? I never really worried a lot with gnats...it takes a lot of them to kill a healthy plant. IMO, they are as much as a nuisance as fruit flies.
 
 
ELCouz said:
From what I understand, fungus gnats are there because there is food attracting them. By food, I mean perfect conditions such has water logged soil that create fungus & rotten roots.
 
Reset the soil with H2O2 then maybe keep the soil humidity lower? I never really worried a lot with gnats...it takes a lot of them to kill a healthy plant. IMO, they are as much as a nuisance as fruit flies.
 
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There's just honestly so many of them, and do the larvae only eat dead roots? I should be getting my mosquito bits to try soon as well.
 
They don't just eat dead roots. Primarily their food source is fungus, the by products, and detritus in soil. But they will sap food and water from live roots. When larvae are feeding from roots it causes stunted growth and deformities of the leaves. In my experience the bacillus will not help alot. They have to eat it in order for it to work. But if they have juicy plant roots then that will be their preference.
 
stickman said:
If you suspect you have a fungus gnat problem, the quickest way to find it is to half-bury a 1-inch cube of raw potato in your potting soil overnight. By morning all those larvae will be cozied up next to the piece of potato, and will be very easy to spot when you remove it.
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Then treat the soil or spoon them all out?..
 
Dane said:
They don't just eat dead roots. Primarily their food source is fungus, the by products, and detritus in soil. But they will sap food and water from live roots. When larvae are feeding from roots it causes stunted growth and deformities of the leaves. In my experience the bacillus will not help alot. They have to eat it in order for it to work. But if they have juicy plant roots then that will be their preference.
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Yes I have noticed stunted growth as well as a few seedlings have somewhat deformed leaves. I'll try and get a picture tonight.
 
Anybody know if a plant that was originally getting messed with as a Seedling by the gnat larvae that become stunted will grow out of it after the problem is under control or is it a permanent damage/stunting thing?

I'm using azamax at the moment and it's working on the larvae but I treated every single plant in my place-42 plants-and still have an adult or two show itself each day which then involves karate moves on my plants which I know they don't like :( smashing leaves! Lol. But it's supposed to wreck their growth regulation hormones and makes em sick and deformed so they're not hungry I guess, but it's rough stuff on the hands and for our systemic system too-even though it's made from neem oil. I suppose neem oil isn't good for the soul either though.. All started from a bag of ocean forest grrrrrr. And overwatering at the beginning. The organic stuff just loves to form mold/fungus which keeps giving them a food source.. Fans fans fans! I can tell they're past getting screwed over though as they're growing nicely now, just had a setback in the beginning..

Regards,
-Tristan
 
Teaks said:
Yes I have noticed stunted growth as well as a few seedlings have somewhat deformed leaves. I'll try and get a picture tonight.
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Yeah I had the deformed leaves in the beginning too until I was shocked and saw the larvae crawling out of the soil! I Literally jumped! The h202 treatment was given after I saw that- what a sight to see em all squirm about! Did that before uppoting from cell trays as didn't wanna bring the larvae on board to new soil, and the h202 knocks out beneficials in the soil like probiotics and good microbes.
So you are in coir and still got them? Are they moldy or what? I was told they don't like coir but obviously I heard wrong..

Regards,
-Tristan
 
My seedlings are now suffering leaf damage and I haven't really overwatered according to the smaller seedlings that kept shriveling up. I guess it's time to treat either way. I may not have initially asked the question, but I appreciate all of the advice in the thread. Thanks everyone!
 
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