Battle of the Fungus Gnats

[lakelady]

And a grueling battle it has been, but I think I'm finally winning. I had no idea what these things were until several members here told me and they were constantly hovering around my indoor tomatoes this Fall. When I finally realized what they were, obviously, it was out of control.

I got the sticky yellow traps at first which were suggested by Ray, and boy did I get a ton of gnats with those. Yet, every morning, I would inspect the plants and lots of little guys were crawling around the soil. It was pretty gross to me. I needed more. I tried neem oil, safer soap, nothing was working.

Having used a lot of essential oils in the past 10 years, I researched and found that Cedarwood (it must be virginiana species) Essential Oil is insecticidal. So, off I went to the basement to dig out my oils. Got a 1 quart spray bottle and in it, in this exact order, I put 1 tbsp liquid soap (I used dishwashing soap), and then 1 tbsp. Cedarwood Essential Oil (It must be Virginiana, not Texas or any of the others). Swirl it around, and then filled the bottle with water. You must first combine the soap and oil to obtain a true emulsion, otherwise they will not mix with the water and you will constantly be shaking it. Actually, my first go around had more cedarwood in it, but the plants didn't like that, it was way too strong, so I settled on 1 tbsp which seems to do the job, and is less upsetting to any drift on the leaves. Spray the top of the soil very well, it KILLS ON CONTACT. Within 5 seconds. Seriously, I even sprayed the few stragglers sitting on top of the pots themselves, and voila, dead. I became a woman on a mission, going so far to spray the air, the window, you name it if there was a gnat on it

Still, every morning, there they were waiting for me. Fewer and fewer, but I wanted them all gone. So I picked up a jar of Gnatrol which Heritage suggested on the other thread, and mixed with water and watered the plants. I can't do a second dose because they are still too wet for more watering, but it is helping. This morning there were far fewer of the devils on top of the soil and I sprayed away whichever one's I saw. I try to check several times daily because it got so very bad, and spray as needed.

By the way, Cedarwood oil is very inexpensive and you can pick it up at any healthfood store for a few dollars; the tomato leaves do not like it, so I gently move them aside when I spray.

Oh, and it also kills aphids too

[Heritage]

lakelady,

That's great you are making progress with the gnats and I think it was a good idea to hold off on the soil drench until the plants need water. Over-watering would undoubtedly do more damage than the gnats. (One of those "winning the battle but losing the war" type deals...)

Good luck!
Steve

[semi_lucid]

lakelady

I've never tried it, but I've read that a layer of sand on top of the potting mix can help with control, because they can't crawl though it.

I've also read that Cedar chips will keep them away. But I've never tried that either. Cedar chips might be toxic to your plant though.

John

[delltraveller]

John,

I used cedar chips to mulch around my tomatoes this year and it didn't seem to bother them at all.

[lakelady]

I did try sand, and it helped, but the problem is, most of these are in regular large pots, so when I watered, sand moved and soil was exposed. I didn't want too much sand in there because the pots get heavy. Cedar Chips probably work in the same way cedarwood oil does. Any insecticidal properties would help with the bugs. I just don't know if the chips would be more of a repellent instead of just killing them. Might have worked early on if I knew what I was dealing with but I thought they were just fruit flies that moved from the vegetables and fruits in my kitchen until someone on TV pointed out they were possibly fungus gnats. By then I was over run with them. Now I know better

[Tania]

Antoniette,

What a battle! And I am so glad to hear that you are winning it.
I had a similar problem in 2009, and it was not pretty. I had about 1000 seedlings back then and it was very hard to manage, and I knew little about the beast. I learned a lot since, but somehow I do not have this problem anymore (maybe bad soiless mix in 2009?), and I am so glad I do not have to deal with it

Keep winning, and good luck with your winter growouts!

[lakelady]

My mom stopped over tonight and went over to check out the tomato plants. I know she's hoping to steal a tomato or two SOON lol.... She came back from the living room looking troubled and asked me "what ARE those bugs"? sheesh. I am beginning to think they are the reason my plants are not looking so great, even though I have buds and flowers. I hope they survive this ordeal.

Oh, and mom did suggest that I change those yellow sticky traps often because she thought the bugs might not be attracted if they saw all of their friends lying there dead.

[rnewste]

Tell your Mom to stop watching "A Bug's Life", or whatever the Pixar animated Movie of a few years ago. New bugs WILL be attracted to the sticky traps - - no matter how many of their "friends" they see stuck there...

If the traps fail to control the situation, you *may* want to consider using this as a last resort:



It is rated for Indoor use - - but personally, I would go shopping for a few hours after spraying it. Here is a link for more information:

http://www.domyownpestcontrol.com/hi...de-p-1551.html

Again, personal choice if you can't find another way to control them - - and you are absolutely driven to grow tomatoes indoors over the Winter, come what may.

Raybo

[Elizabeth]

Another option is Gnatrol. It has a BT israelensis. It kills the larvae when you use it as a drench and isn't toxic to people and pets.

[lakelady]

Elizabeth, I did get gnatrol. I used it as a soil drench on a few, but some of them have not needed water, and I was afraid of overwatering the containers as these indoor tomato plants seem a bit sensitive. Hopefully though, with a 3 pronged approach, I'll win. I did put the sand over the top of soil on the plants, but each morning I find teeny tiny babies on it too, so maybe the adults cannot get in, but the babies certainly seem to be able to get out.

[happyseedplanter]

Here is some methods to try and get rid of fruit flies.

Let the flies sit in a bowl on the counter, with the surface tension broken. You can forgo using a funnel if you put a small bit of dish washing detergent in the cup with the vinegar and stir. The fruit flies are still attracted to the vinegar smell and the detergent traps them. The detergent actually reduces the surface tension of the liquid, allowing the flies to more readily sink and drown; if the fruit flies fall in, it sticks to wings so they cannot fly. Use a little fruit or juice to help attract the fruit flies.

· Any small container with a teaspoon of cider vinegar, 2 tablespoons of water, and a drop of two of dish soap will attract and drown fruit flies. To kill off the rest of the population, try pouring a cup or two of warm/hot vinegar (can be diluted with half water) down your kitchen and bathroom drains.
· Fruity smelling dish washing liquids (lemon, etc.) will attract fruit flies

[David52]

Using mosquito 'dunks' or granules is very effective on fungus gnats - I buy a container of granules and sprinkle about a teaspoon on the top of the container soil. Thats all you need. Its a closely related - if not the same - strain of BT.

Find it extremely helpful with seedlings, always put a few granules in with the tiny plants as well. No more fungus gnats eating the root hairs.

Link is the product at Amazon:

http://www.amazon.com/Mosquito-Dunks...mosquito+dunks

[KarenO]

I think the secret is to catch the flying adult gnats who breed and lay the eggs by using the sticky traps. Use several per plant near the soil and change them when they are getting "Full". Control can be the goal as opposed to total eradication and that may depend on your taste for insecticide. Personally, I would not use anything other than an insecticide rated for use on indoor and edible/food plants but that is up to you.

[David52]

I use the mosquito dunks in all my indoor ornamental plants as well. The Bt is a bacteria that forms crystals in the tummies of larval mosquitos and fungus gnats. Not particularly toxic, unless you're a larvae or caterpillar.

[Cole_Robbie]

I agree about the BT. Otherwise, you'd have to cover all of your exposed soil with dry perlite or plastic to deter them. They are more annoying than they are damaging.

You could just get a bunch of spiders, and that would solve your gnat problem. Spider webs are nature's sticky trap