HELP Fungus Gnat invasion

I have a shelf with fl. lights where I keep some cactus and succulents, some all year some just for the winter. I also have some Nepanthes and sundews. I got some new sundews (5) and now I see gnats in the LFS moss in the CP pots. How the devil do you get rid of these? I don't think they will bother the other plants, too dry. But I did have to toss one orchid that was in prime agra (sp?) rocks that was full of them. I checked the other orchids and they seem fine. Suggestions? I got to get rid of these things!!!!!!!!!!!!!!!!
C

I have not tried this myself yet (I have a few fungus gnats but they do not bother me just yet) but a through spraying of Insect Soap might do it. More power? Try a household bug spray? Do they live in the soil? Can you re-pot everything in bug free soil?

CP plants are pretty sensitive to things sprayed on them. I did find them living in the soil, YUK! Someone on the carnivorous plant forum said you could use mosquito dunks and that is what I did today. Won't kill the fliers so I ordered some sticky traps but is should take care of the larva. I will post how well it worked.
Cheryl

Newton--

Fungus gnats are a pain--they are always flying around and always near the plants.
I use sticky traps near my potted plants and catch hundreds and hundreds of them.
Still they are everywhere I sit or eat or am looking at the newspaper. Certain thins attract them.

Your main focus should be treating the soil in your pots. That is where all the problems start.
These Gnats lay their eggs in the moist soil and there they hatch into small larva that feed on the plant's roots.
The adults (the ones flying around) life cycle is about 2 weeks.
Spraying in the house will not help! Gotta get them at the source.

There has been so much discussion here on how to deal with Fungus Gnats.
A few obvious ones--is to keep the soil of your potted plants drier, They need moist soil.
Put something on top of the soil that the Gnats will not be able to go through. Sand may work.
Using a Systemic spray or granules will kill whatever is in the soil.

Here is a link that may help you. http://www.ghorganics.com/page9.html

You could also go to the "Pests and Diseases" Forum and ask there.

Gita

This message was edited Jan 31, 2013 9:18 PM

Carnivorous plants require wet soils so that is not an option. I did use the sticky traps and they caught a lot of adults. I also tried using mosquito dunks in water and that worked pretty well. I put a chunk of one into the watering can and water the potted plants with it. It seemed to knock out most of the larva. I will have to be more diligent in the future and not let their population get out of control.
C

Newton---

Well--looks like you know what to do. All my instructions were not necessary...

I just took a picture of what my sticky pads look like. There are 100's of Gnats stuck to them--on both sides.
These are hard to find. I ordered them from the "Planet Natural Garden Supply" catalog last January.
They were $8.95 for a pack of 25 plus $3.50 for a pack of wire stakes to stick them into.
They are 3x5 cards--bright yellow, sticky on both sides. www.planetnatural.com .

Here is my picture I just took. This is my small light set-up I use for cuttings and, later, growing seeds.
They really work well--both sides are covered with dead gnats.

Good luck in your 'war" on these pests. Gita

I just ordered Systemic Granules and Mosquito Bits ( for when mosquito dunks are not handy.)

Someone else on another forum gave me the ideas. I can't say as I thought of using mosquito dunks on my own.

I love the dunk idea! At one point I brewed up some tobacco tea and used that for a couple of weeks. I'm not sure which remedy was most successful (I tried a lot simultaneously out of desperation) but I feel the tobacco tea combined with sticky cards might have been what sealed the deal. Now I just leave sticky cards in plants and remove when I have guests over...since they aren't so glamorous (the cards, not the guests).
I have access to dunks galore so I'll have to remember that.

Applied systemic granules to all the pots with gnats (plants that I would not be harvesting for consumption and can't let dry out) last week. Seems to be doing the job. Just got my Mosquito Bits today. Applied to all Citrus pots that had gnats. Have my fingers crossed. Gene

This message was edited Feb 11, 2013 2:26 PM

Has anyone heard of adding hydrogen peroxide to H2O and misting soil? Ratio 1:10
Am I expressing hat correctly? I part peroxide to 10 parts H2O

I'm having gnat issues..... What are mosquito dunks?

Kiley

I now use Azamax as a soil drench. Takes a while but it does indeed do the job. Gene

Kbh69,

I talked to a wholesale grower about mites--and he said they use
Hydrogen Peroxide in the 1:9 dilution to control Spider Mites.
think it is good for many other things as well...just nothing comes to mind.

A long time ago--a commercial plant person (the ones that take care of office plants)
told me to water plants with 1Tbs. of Ammonia to a gallon of water.
Not sure if this is correct--my memory is not that great any more...

IIf your soil stayed drier--there would be less gnats too.
Have heard that a layer of sand or gravel will deter them.
And--Diotomatious Erth for sure. Just be VERY careful using it!!
Mostly--DO NOT inhale it. It is powdered silica--which is glass.
HD and Lowes both sell it.

Gita

Use Azamax for spider mites. It is organic, safe. Works like a charm. If it was 60 years ago I could understand the use of "home remedies." However, in this day and age I just do understand people putting milk, peroxide and such on their plants when there are newer, safer alternatives available. Gene

This message was edited Sep 28, 2013 9:31 AM

True....true. I was just trying to think of things I could use that I already have. I'm frugal.

My priority is having nice, healthy plants.

I'm also willing to move on to more effective solutions without delay. I want "nice, healthy plants" as well!

Thanks for the feedback.
Peace~
Kiley

Gitagal, thanks for the ghorganics link. My gnats are all but gone! The powdered gnat stuff really works! It stressed a few leaves on two plants, but so worth it. Thanks so much. Same ingredient as mosquito dunks, just much easier to stir.

Thanks again!
Kiley

Re those yellow traps- I think someone has said that yellow SOLO cups are the same color, and you can coat them with Vaseline to make the gnats stick. Cheap. probably worth a try.

SUPER neat idea. Just my style of thinking.
Glad to see your googley eyes ms. sallyg!

You can also apply Vaseline to 3"x5: index cards and hang those.
Or--anything else--for that matter.....

Those sticky cards are NOT cheap to buy! G.

Does the color of the index cards make a difference?

kbh69

From what I know--Gnats are attracted to bright yellow, so you would have
to paint them yellow. Make sure you make a hole at the top to hang it by first.
You may be able to find some heavier paper than index cards. Like card stock.

Craft stores sell Acrylic paints in those small bottles. Every color on earth.
Do you have a "Michael' s Crafts" anywhere near you? Joannes Fabrics?

They cost about 59 cents a bottle. The colors are permanent when they dry

Vaseline is a bit opaque. Petroleum jelly is more clear. Both are similar.
I use bamboo skewers. Cut them any length you need.
Find some soft wire (one you can bend) and twist it around the top.
Extend the end out about 2" and make a little hook on the end.
Hang the coated card from the hook and insert the skewer in the soil.
Make sure the card does not touch the plants.

Gita

Sounds like a project my Tween and I can do together! What fun!

The gnats are basically under control, but I have a Palm I'm trying to save that needs misting. A few cards posted around it would be a huge help! This is great. Very creative. Thank you.

Kiley

Fungus gnats are really annoying, but their larvae eat the new tender roots of your plants and can kill them. I use a product called Knock Out Gnats. It used to be a liquid, but is now in granular form, and lasts much longer. It contains a variant of bacillus thuringesis (sorry if I spelled that wrong) that when applied as a soil drench wil activate the bacilli and they will devour the fungus gnat larvae, which is the part of your invasion that keeps it from stopping at some point. You'll have to treat your plants a few times at roughly one-week intervals in order to kill off subsequent populations of larvae from existing gnats laying eggs in the soil, but it will eventually be a cure.
A friend of mine is an entymologist, and one time she brought over the darndest cure for fungus gnats I've ever seen. She had inoculated waxworms with a type of predatory nematode that devoured the waxworms and populated like mad. I drew off some of the resulting flood of nematodes with an eyedropper, put them in water, and watered my gnat-infested plants with them, and I've never seen such a sudden absence of gnats! It was miraculous. She is my hero for that very reason.
You'll need to set up petri dishes for that, but I'm sure the recipe is online, if you're willing to go to that trouble.

Would Systemic Granules also work on the gnat's larva?

It is something i have and could use. Hate to spend $$ to buy new stuff.
I have so much of everything...

I hear ya Gitagal!

I used a systemic granule put out by Bonide. It came highly recommended in an article on this site. Not the specific granule, just a Bonide systemic. I've used it once and it has been nothing short of miraculous. It took a good week for the gnats to disappear, but they are 98% gone. I've seen a few.... Literally. Good stuff. Doesn't smell bad. Easy to use.

Systemic specifically for container plants.

Yay!

Kiley