So, I was seeing some fungus gnats on the young trees that I will be keeping inside my house for the winter. I decided to try a mixture of Diatomaceous Earth and ground up Mosquito Dunks (2 Dunks to 4 cups D. Earth) to terminate them. Diatomaceous Earth is used in pool filters, as a mild abrasive,as an absorbent for liquids, as cat litter, and as a mechanical insecticide. It is made up of fossilized diatoms, a type of hard shelled algae. It is 90% silica,2-4% alumina from clay minerals and .5 to 2% iron oxide.

I use it in my garden to control aphids and it has eliminated the Gooseberry sawflies. Our family dog doesn't get fleas, because we carefully dust her with D.E. during the flea season. It has to be re-applied to plants after a hard rain and care must be taken not to breath in a big cloud of it, if it is a windy day. It could irritate if a large amount was breathed in. I find it to be a great organic, natural pest controller.

It can be purchased at Home Depot or over the Internet from a variety of venders.

There is even a food grade Diatomaceous Earth that can be ingested by humans as a source of silica and as an anti-helminthic. It kills bed bugs, so could be a great way to address that big problem. Under a microscope, the particles are sharp and irregularly shaped. These diatom particles pierce soft insect bodies and desiccate them. It kills by physical action, not chemical, by puncturing the insect's exoskeleton and absorbing the moisture in their bodies.

My trees are on treatment day #3, since sprinkling the top layer of soil, in their gallon pots, with the dry mix of Diatomaceous Earth and ground up Mosquito dunks. I added in the ground up mosquito dunks because they contained B.T. (Bacillus Thuringiensis v. Israelensis in a solid form)Other forum members have had a measure of gnat control from watering their young fig trees with some mosquito dunks dissolved in water.

So far, I don't see anymore gnats. But I plan to continue the treatment for the next month. Fungus gnats take six days to hatch, feeding on tender roots for 2 weeks, then pupate for less than a week in the soil and emerge as adults. And on it goes, ruining young fig trees. I don't know what the long term effects will be on my fig trees, but will be posting again in a couple weeks to update and report the results. Since it is a desiccant, I was careful to keep the powdered mix off the leaves and stems as well as the little tree trunks. I think this is going to work and if it does, it would be great if other forum members could benefit.

Eve (zone 5b)

Eve,

I am unfamiliar with moquito dunk. Do you also get that at Home Depot?  How do you "grind" it?

C.J.

Hi C.J,

Mosquito dunks are available at Home Depot in the gardening section. They are shaped like a donut, dissolve slowly while floating in water, and are used in ponds, birdbaths, pet water dishes and standing water to control mosquitoes. The active ingredient is the BT. (Bacillus Thuringiensis v. Israelensis in a solid form) I don't think I would add it to a pet's water dish? But they work good in my rain barrels.

I put them in a heavy duty freezer bag and tapped them with a hammer to break them up to a rough powder. I mixed in 4 cups of diatomaceous earth with the ground up dunks and dusted the top of the soil with it. It has to be reapplied after watering to keep some of the dry mix on top.

After a couple more weeks, I will post a follow up on this method. This may not work, so if anybody else has had success with another method, please share. I don't want to go through that gnat problem again. They are beasts. Lol

Eve

Oh yeah!  Fungus gnats are a real pain in the butt!

I saw the mosquito dunks and Home D.
Question can i simply break them into a powder mix (i will pulverize them) with water when the time comes and lightly water upper part of soil to stop the cycle of them ?
I dont recall seeing anything on package that suggested this procedure and wonder if it would hurt the plants root sytem .

I ask as in past i had at least 6 sticky strips in circled around plants and yes the adults would get stuck to them but the gnats kept multiplying none the less in soil of plants. This season if they come around i need to break the cycle in the soil to stop them .

I was not going to grow indoors but anyways im going to try a few things so in short i will be.

Im even thinking of somehow to enclose top of soil with plastic grocery bags tied to stem after a treatment if it comes to that. Then un tie when i need to water them.

Hi, yes you could grind the mosquito dunks up, dissolve in water and water with the mixture or try these products that CJ(jenia)told me about. Look up Gognats & Gnatrol, on the Internet.
Both products sound like they would work [U]and thanks to CJ[/B] for searching for and finding these products. I am considering ordering both since I'm bound to need them in the greenhouse plus I really want these gnats to be gone.
The gnats are a pain and so far I'm still seeing them in the little trees.

To Gorgi, thanks, I'll try some sticky fly strips too.

Eve
Zone 5b-6
Buffalo,NY

Thanks all for the information.
I still have few stick strips left from previous and there cheap also, i figure once adults are airborne they already layed there eggs and to have measures against both of them adults and eggs, the soil control stuuf along with the strips perhaps might might do the trick.

Funny though last time i grew indoors i nuked the soil in the microwave and got it smoking real good and figured any eggs inside would be toast it was a hassle to do and took long time for amount needed i had but they must have been on the plants and or scion as well  i guess. Yes i had water inside microwave as to make sure i did not damage machine !

Time will tell what happens this season indoors .

I have found whole bottles of BT at my farm co-op for about $15. I think that is what I use to control cabbage worms. For fungus gnats I have always just used a few drops of soap in the water I am watering with. The soap kills the larvae. They get to be a problem in the greenhouse and the soap has always worked for me.

Susan

Hi Susan,

What kind of soap do you use?

Thanks,

noss

Noss, I use either Dr. Bronner's castile soap from the health food store or an insecticidal soap. Which ever one is the most handy. I think that Dr. Bronner's is less expensive and it works just as well as an insecticidal soap for everything. It is the very best thing to use for spider mites, too. I also use it for scale.

Susan

Thanks, Susan.  I added this thread to my Favorites for future reference.

noss