Fungus gnats

[Coug1975]

Appears as tho the fungus gnats have hit me hard. Overnight plants starting to lose leaves on bottoms. I have sprinkled cinnamon in all pepper and tomato plants. Now am letting dry for a few days and apply a diluted hydrogen peroxide mixture to kill any active larvae. Anyone else have any other thoughts?

[bower]

Definitely recommend the 'mosquito dunks' or 'mosquito bits' which are forms of BT-i. You water with it or water it in, it's a bacterium that will kill the larvae especially at a certain stage. Quite a decent amount of control although I did have to repeat a fair bit.
Also, use yellow sticky traps down by the soil, it will catch the adults and reduce the amount of egg laying. Fungus gnats really suck.

[Tracydr]

I put oil sorb Diatomaceous earth on my citrus trees recently when I noticed them on the lime tree. About a 2" later. The leaf curl on the lime is almost gone and it's only been a few days.
I also know that the BT used in mosquito dunks will work better than anything and I'll probably get some in case the DE isn't enough.
This is the DE we use to seed start in,not the stuff dusted on plants as an insecticide.

[Coug1975]

Ok thanks. I will maybe try mosquito dunk. Do you know if it is able to be used in organic gardening?

[bower]

Originally Posted by Coug1975

Ok thanks. I will maybe try mosquito dunk. Do you know if it is able to be used in organic gardening?

If I recall, (last year) the 'Mosquito Dunk' product is okay for certified organic producers in the States but was not approved in Canada. Something about the binders for the BT-i, or maybe the binders themselves were not 'certified'. The Dunks use cork as a binder afaict, and corn is used in the Mosquito Bits - could be it's conventional corn. BT-i itself is organic and certifiable, but the question what else is included, the certifiers can be picky.
It is for sure okay for organic gardening, but for organic farming, you may want to check with your certifier for sure.

Another example, we use slug baits here which are approved for certified organic, but last year there was a cufuffle about some brands not being accepted. They are all the same active ingredient, a harmless to us iron compound that kills the slugs when they eat it, plus some kind of binder. Approved or not, it's about the binders.

[Coug1975]

The ones I have for my duck pond are listed as safe on one organic site we looked up so it is done. Hopefully I caught it o. Time to save them all.

[Gazeofslate]

I've been noticing a few gnats flying around my pepper plants and tomatoes recently, and a few cuts in my pepper plant leaves. Are gnats harmful to plants and could they cause these cuts in the leaves ?
They're a bit annoying because they keep flying around -even though they appear to be poor fliers and seem to prefer running around.
If they're not a problem and if they are not responsible for these cuts I'd prefer not to kill them then as long as they're not too numerous. I guess they could even be somewhat beneficial if they feed on fungus as their name implies ?
Here's a picture of the cuts below :

[bower]

Gazeofslate,
Those cuts are not caused by fungus gnats.
But fungus gnats are a serious pest especially indoors/ potted plants. The adults don't do anything but lay their eggs. You can cut down on that by catching them with sticky traps.
The eggs laid in the soil are really the problem. The larvae will eat the roots of your pepper plants, and it's no joke, there's nothing beneficial happening. I've seen them kill pepper plants. Roots simply swarmed with fungus gnat larvae.... then nothing left but a dead stalk.
For some reason they're not a problem outdoors here. Maybe too windy for them.

[Gazeofslate]

Ok, well time to squish these things then. Thanks for the tips ! I'll try and look if I can find sticky traps. I guess we can't just hope for these things to drown when watering the plants.

[Al@NC]

Last season I had gnats so bad that the seedlings stopped growing. I caught it early enough in the season that I actually took cutting from my seedlings, put the seedlings in solo cups with water and let them form another root system. It saved me weeks from having to start from seed again but it sucked compared to prevention to begin with.

Mosquito dunks made all the difference this year, I bought some and put them in at first sight of gnats.

Al

[bower]

Me too Al, I had some dunks left over from last year and swiftly applied when I saw one gnat!

How many times did I get to the "doom day" past few years - you water the plant and it doesn't take any up! You look at all the water in the tray and hundreds of the little suckers are paddling around there. And the poor plant has no roots left to absorb anything. I actually did collect a tray of the little hellions for observation, to see whether they drowned or not... no! Water won't kill em that's a fact. So relieved to find the BTi products.

[Gazeofslate]

Doesn't seem like a huge problem right now as my peppers are fully grown plants that are roughly a year old now and have bark on the stem but I'll probably have to do something about this before it goes out of hand. From what I read on the wiki article about them they're mostly a problem with seedlings as they seem to be a damping-off vector. It said they only chew on rotten roots but do I really want to know ?! I don't picture half a dozen gnats eating the whole root system of three grown plants but really, I don't want to know.

[Scooty]

http://www.tomatoville.com/showthread.php?t=41252 These are some pics of what fungal gnats and their larvae can do to tomato seedings.

Here's another picture. You can see the dead fungal gnat hanging off the stem after a day of spinosad. Mosquito bits took care of the larvae.