pests Fungus gnats!

RedtailForester

RedtailForester

Good morning all!

I have been plagued with fungus gnats for the last couple of seasons. For those of you that aren't familiar with these Littles bastards, it is their larvae that cause the problem. They will infest your growing medium and eat your seeds from the inside out.

Does anyone have any suggestions for getting rid them? I literally use new starting mix and wash my germ trays every year. I have no idea where they are coming from!!!!!
 
Steinernema feltiae nematodes... have used these a couple of times, and after little more than a week all fungus gnats are gone!
 
One thing we did was to eliminate all natural peat or soil bases for our soil/starter mixes, we use coco coir pellets & bricks.
Rich Organic soil is what they live for so don't give them food to start with. We also use a Bio fungicide to water & mist
our seedlings. That controls the food supply Fungus.

Fungus Gnats such a problem, we have as many solutions as people who are trying to kill them.


I read this & wondered why you can't just use Thuricide for FGs?

What is Bti? Is Bti harmful to humans, pets, my plants, or the environment?

First discovered in Israel in 1976, Bti is a biological or a naturally occurring bacterium found in soils. Bti contains spores that produce toxins that specifically target and only affect the larvae of the mosquito, blackfly, and fungus gnat. Since humans, animals, birds, and fish have acidic and not alkaline digestive tracts, Bti toxins have no effect and has been approved for pest control in organic farming operations. It has been well tested by many studies on acute toxicity and pathogenicity (ability to cause disease) for Bacillus thuringiensis including studies specifically on Bti. Bti can be applied safely to fungus gnat habitat without a detrimental impact on food crops, water supplies, or honey bees and can be used up to the day of harvest on all edible plants.
 
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fire flames GIF
 
Downriver said:
@RedtailForester Hey Dan, look at using a Hydrogen Peroxide flush.
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Second that!

I did the hydrogen peroxide (H2O2) one year, worked wonders. Also I appreciated that its basically just H2O with extra O. Not sure if it was the H2O2 or the incessant deer toppings that year, but it was one of my most productive seasons.

Ultimately I had to started sourcing soil from places that treat soil better. Most big box retailers and hardware stores do not care about your grow medium.

2 cents.

Good luck this season! 🌶
 
@Marturo The ecosystem appreciates your non-peat stance. It’s still organic material though and that is what they want. Maybe a full perlite grow would fit that narrative but that is a lot of work.

@RedtailForester I have only had them once and it happened from getting lazy with my growing practices. All the suggestions here sound great but they reproduce in drains and other areas in the off season.So the only differing spin I can add is to not only use the yellow sticky traps which kills what lays the eggs,but leave them up in your tents,growroom,etc. all year to keep your foot on their little necks.
 
Pr0digal_son said:
@Marturo The ecosystem appreciates your non-peat stance. It’s still organic material though and that is what they want.
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So far not getting a big problem with Gnats using the Coir.
This is what I will use for a prophylactic & a treatment if necessary.

 
I had a horrible time with them last season, too.

But, I was bottom watering and leaving a lot of water in the trays so I had a lot of mold on top. This round, I hit the six packs with neem oil several times via spray bottle before the seeds sprouted and I have several yellow sticky traps among the sixpacks. I haven't really seen any fungus or trapped more than a couple of fungus gnats by keeping things a little less wet. No algae yet either. 180/390 have germinated so far, waiting on a few stragglers, mostly the superhots. My soil is Miracle Gro performance organics.
 
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Marturo said:
One thing we did was to eliminate all natural peat or soil bases for our soil/starter mixes, we use coco coir pellets & bricks.
Rich Organic soil is what they live for so don't give them food to start with. We also use a Bio fungicide to water & mist
our seedlings. That controls the food supply Fungus.

Fungus Gnats such a problem, we have as many solutions as people who are trying to kill them.


I read this & wondered why you can't just use Thuricide for FGs?

What is Bti? Is Bti harmful to humans, pets, my plants, or the environment?

First discovered in Israel in 1976, Bti is a biological or a naturally occurring bacterium found in soils. Bti contains spores that produce toxins that specifically target and only affect the larvae of the mosquito, blackfly, and fungus gnat. Since humans, animals, birds, and fish have acidic and not alkaline digestive tracts, Bti toxins have no effect and has been approved for pest control in organic farming operations. It has been well tested by many studies on acute toxicity and pathogenicity (ability to cause disease) for Bacillus thuringiensis including studies specifically on Bti. Bti can be applied safely to fungus gnat habitat without a detrimental impact on food crops, water supplies, or honey bees and can be used up to the day of harvest on all edible plants.
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what about carrot fly maggots, do you think BTI will kill these also? do you have another solution?
 
Like I said in the beginning of this thread... nematodes are the best solution, no pesticides needed. I use them when the pest gets really bad and in little more than a week time all gnats are gone!
 
Marturo said:
One thing we did was to eliminate all natural peat or soil bases for our soil/starter mixes, we use coco coir pellets & bricks.
Rich Organic soil is what they live for so don't give them food to start with. We also use a Bio fungicide to water & mist
our seedlings. That controls the food supply Fungus.

Fungus Gnats such a problem, we have as many solutions as people who are trying to kill them.


I read this & wondered why you can't just use Thuricide for FGs?

What is Bti? Is Bti harmful to humans, pets, my plants, or the environment?

First discovered in Israel in 1976, Bti is a biological or a naturally occurring bacterium found in soils. Bti contains spores that produce toxins that specifically target and only affect the larvae of the mosquito, blackfly, and fungus gnat. Since humans, animals, birds, and fish have acidic and not alkaline digestive tracts, Bti toxins have no effect and has been approved for pest control in organic farming operations. It has been well tested by many studies on acute toxicity and pathogenicity (ability to cause disease) for Bacillus thuringiensis including studies specifically on Bti. Bti can be applied safely to fungus gnat habitat without a detrimental impact on food crops, water supplies, or honey bees and can be used up to the day of harvest on all edible plants.
Click to expand...
Who remembers BT powder hand crank dusters?? Cough,cough
 
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I've germinated seeds and raised seedlings during fungus gnats infestations with great success rates. Good germination practices and good seeds should get the job done fine and without noticeable effect from the larva. I've also run tests on H2O2 "flushes" at significantly higher concentrations and even soaked larva in higher concentrations and my results suggested H2O2 flushes aren't effective or at least aren't strongly effective, particularly at that level of dilution. I think mosquito dunks or other BTI products are far better treatments, provided you get fresh product.
 
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CaneDog said:
I've germinated seeds and raised seedlings during fungus gnats infestations with great success rates. Good germination practices and good seeds should get the job done fine and without noticeable effect from the larva. I've also run tests on H2O2 "flushes" at significantly higher concentrations and even soaked larva in higher concentrations and my results suggested H2O2 flushes aren't effective or at least aren't strongly effective, particularly at that level of dilution. I think mosquito dunks or other BTI products are far better treatments, provided you get fresh product.
Click to expand...
can i ask what dilutions you tested with?
 
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