New Grower Fungus Gnat cures, preventions, and urban legends.

[Feenix]

Orrganic:

Over the years I have released Green Lace Wings, Lady Beetles, Praying Mantis, several types of parasitic wasps and nematodes. There is other stuff I just don't remember now. They all overwinter and go to work every spring. Last fall I found a fly with a long proboscis poking a tomato hornworm.I have never seen one before and could not identify it? I am sure it was parasitizing it but my foot is a guaranteed hornworm killer. I like to take my cat out into the tomato patch in the early evening and watch her ears as she can hear them chewing the leaves. It is like having a hornworm detector; when both ears aim together I look and there will be one - squish. She only has enough patients to get a couple of them before her attention turns to something else. If the outbreak gets past just a few I use the BTk.

Ever run into the potato beetle?

They released millions of them out back of my home to eradicate the invasive Air Potato. I've been lucky with only one getting to my grow. I sat and watched it contaminate a seedling I was, again, time lapsing. They look enough like
lady bugs to the untrained eye to think "Lucky me, a lady bug." Now I know the difference.
I appreciate you straightening me out on the nematodes and dunks. Not the first time science has passed me by. But I have not had one problem with the gnats since I started preventive dosing with them when prepping. Even though my fly strips regularly fill up with the adults. I don't use the fine sand topping or other prevention so when the gnats are there, they are laying eggs. Since the dunks are the only thing I use, I have to think that there is some benefit from them. Could there be some unknown side effect such as perhaps sterilization by an additive in the formula or other off the wall reason my seedlings have not been falling over anymore?

 

[Renaissance Redneck]

Another great cultural treatment for fungus gnats and other critters that use soil as part of their life cycle is diatomaceous earth. Incorporated into the upper soil profile, it is a powerful desiccant.
Food grade can be spendy, but it can be had at farm stores for next to nothing. A 40 lb bag only costs 15 or 20 dollars, I even feed it to our chickens as a natural preventative for intestinal parasites.
Just don't use the stuff sold for pool and spa filters, it's calcined (treated with very high heat) and I would consider it a type of poison because of it's high crystalline silica content, as well as higher lead and arsenic content.

 

[orrganic]

I don't know if it's been mentioned but sand on the surface really helps with gnats . Rips their wings off when coming out of the dirt, then can't fly and spread.

I have some aquarium medium stuff that is like very coarse sand and appears to be glass... I think I'll add the on top for good measure. Thanks for the recommendation!

I've also had a brief look for mosquito dunks and only found the north american product you are all familiar with.

 

[Feenix]

I have some aquarium medium stuff that is like very coarse sand and appears to be glass... I think I'll add the on top for good measure. Thanks for the recommendation!

I've also had a brief look for mosquito dunks and only found the north american product you are all familiar with.

I've read that the main advantage of the top cover of fine sand is that the gnats don't dig, but hide their eggs in the nooks and cranny's of a textured surface. Fine, powdery sand leaves them nowhere to lay them. So they move on. I tried it once but after two or three , or one watering, it was all messed up and useless.

 

[orrganic]

I've read that the main advantage of the top cover of fine sand is that the gnats don't dig, but hide their eggs in the nooks and cranny's of a textured surface. Fine, powdery sand leaves them nowhere to lay them. So they move on. I tried it once but after two or three , or one watering, it was all messed up and useless.

Yeah well the bucket of this stuff weights a ton so even a thin layer is going to be an overall mess as I'm not planning on dumping the soil it will likely sink and just add weight and aeration if anything. So I might play out, the plants looking quite healthy for having had them its whole life.

 

[Feenix]

Yeah well the bucket of this stuff weights a ton so even a thin layer is going to be an overall mess as I'm not planning on dumping the soil it will likely sink and just add weight and aeration if anything. So I might play out, the plants looking quite healthy for having had them its whole life.

Sounds like aquarium glass. I have a bucket of that around somewhere. It is heavy. All different colors. Never figured a grow use.
My only losses were seedlings, has anyone lost a mature plant to them? I'm no authority. Just know what has worked for me. The powdery sand explanation makes sense. No place to hide the eggs. but a drip feeder would be a good idea so only spots would be disturbed or injection under it even better.

 

[Feenix]

I've been hearing about Green Cleaner, something like that, have you tried it on these things?

Could that have been Simple Green?

EDIT: I found it.
here is an ad.


This is similar to the Insecticide soap I had been warned off of here when I brought it up a couple/few years ago because it built up on the plants surface. This appears to have dealt with that with the addition of the alcohol .

 

[trailanimal]

Usually insect problems are self correcting in my greenhouse. bugs show up, awhile latter predators show up. I have a stash of diatomaceous earth, and I'm going to get some Green Cleaner to have on hand just in case!
I'm sure the extreme cold limits how well invasive insect species over winter up here. Plants are already well established by the time insect populations have grown enough to become a problem.

Also, for some reason unknown to me, One plant in the entire grow will attract bugs, that's where I see damage, 3 weeks to 1 and 1/2 months in. Predators must be showing up about this time also, new growth completely covers and replaces the damage, and plant begins to have a "no worries" look.

 

[orrganic]

So I've scraped the top layer of dry, depleted and infested soil, which was more like coco after being fed from for months and replaced it with fresh, rich compost/soil improver .

This should give it a boost to get through week 6 until harvest without nutes and take a bunch of bug eggs with it.

 

[Feenix]

Usually insect problems are self correcting in my greenhouse. bugs show up, awhile latter predators show up. I have a stash of diatomaceous earth, and I'm going to get some Green Cleaner to have on hand just in case!
I'm sure the extreme cold limits how well invasive insect species over winter up here. Plants are already well established by the time insect populations have grown enough to become a problem.

Also, for some reason unknown to me, One plant in the entire grow will attract bugs, that's where I see damage, 3 weeks to 1 and 1/2 months in. Predators must be showing up about this time also, new growth completely covers and replaces the damage, and plant begins to have a "no worries" look.

Are there active insects outdoors up there in winter?
I'm going to stick with what is working for me. Apparently the nematodes in my pots came from the worm farm that is also a plant nursery I'll ask the guy on my next visit there.They were not enough to save the plant.

So I've scraped the top layer of dry, depleted and infested soil, which was more like coco after being fed from for months and replaced it with fresh, rich compost/soil improver .

This should give it a boost to get through week 6 until harvest without nutes and take a bunch of bug eggs with it.

This doesn't look like she's ailing from much. Beautiful job.