Knats hinding under my Cilantro like crazy!

reversethongApril 15, 2009

I've got a bunch of knats or little flies hiding in my Cilantro pot. They don't seem to be doing any harm, but they are gross. Any ideas at to why and what would be a good way rid myself of them?

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ksrogers(EasternMass Z6)

As mentioned in may recent posts. Guggest that ou do a simple search for the key words 'fungus gnats' and it will bring up numerous posts. These are fingus gnats and are nasty when it comes to spreading too all plants very fast. I use yellow sticky traps layed horizontally on the edges of the pots. The traps soon fil up with many of the gnats. They lay eggs and the maggots in the soil will feed on tender thin roots and reduce the plants health. Simply pouring water on them will not kell all. I have seen people also dunk the roots in warm ater to help drown them, but thats still not good for young plants. There are two organics used for the maggots, a form of Bt watered in, or benefical nematodes suitable for their control. If its outside the nematodes work best. Indoors ALL plants can get infested with these very quickly. The sticky traps only catch the tiny flies, so you need to have two methods to get rid of them. Gardens Alibe has knockout gnats. I have Gnatrol an expensive Bt liquid mixed with water.

    Bookmark   April 16, 2009 at 1:53PM
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Gross, thank you.

    Bookmark   April 17, 2009 at 12:22AM
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novice_2009(zone 6b)

I've got this same problem. Bought plants from home improvemt nursery, and here came the whiteflies! Now they are on my seedlings, and other plants as well. Hate them, and wondering if sticky traps really work. It's become an infestation, and I'm mad. Let me know if you come up with a solution. Thanks!

    Bookmark   April 18, 2009 at 12:53AM
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ksrogers(EasternMass Z6)

Neem spray will kill these white flies which are different from fungus gnats. There is a blueish green sticky pad that will attract white flies, but is not as effective as the yellow traps that are set horizontally on the edges of the pots. My yellow traps were just loaded with tiny gnats, within 2 days. They came in from some potting soil I had in a big plstic container outside all winter. I wanted to try and root some rose cuttings, but they didn't take. Yes, many greenhouses and nurseries are infested with these bugs and they carry over to peoples gardens. I had many white flies on my pole beans, and could see many fleeing when I approached beans. They didn't seem to do much damage, but just seemed to be somewhat of a pest. I sprayed neem in the late afternoon and, it seemed to help. The white flies tend to hide underneath the leaves.

    Bookmark   April 18, 2009 at 10:34AM
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novice_2009(zone 6b)

Wow! After doing some researching, it's fungus gnats, not really whiteflies. Love moisture. I have neem oil, I'll dilute it with water, and try spraying. those gnats are all throughout my house now, even in the bathroom! I'm not sure if they do harm or not, but how could they be good for my seedlings? I'll have to move some plants outdoors to spray? Organic methods only.

    Bookmark   April 24, 2009 at 10:16PM
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ksrogers(EasternMass Z6)

There is a form of Bt that is mixed with water and you water the soil with it. It can kill the maggots. Te yellow stcky traps are also gteat collectors for the gnats and I had one 4x6 inch pad just loaded with them within a few days. Yes, they can fly all around the house looking for suitable places to lay eggs.. The gnats are about 1/5 the size of a whitefly. My first guess was right on the mark.

Yellow sticky traps-,05-244,default,cp.html

Here is a link that might be useful: Gnat maggot larve insecticide

    Bookmark   April 25, 2009 at 1:50PM
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Did you try repotting? Pull the plant, soak the roots in slightly soapy water (dish soap/ivory soap/natural soap)to loosen enough soil so that you have a partially bare-rooted plant, repot in a sterilized pot (bleach it & if it is clay, bake it in a 250 degree oven for 20 minutes or so) & in sterile potting medium. Make sure the pot has good drainage-- both in the bottom of the pot & by elevating the pot on small stones or "pot feet" to keep it off the surface below it so the soil dries well between waterings to discourage the growth of fungus. Good luck.

    Bookmark   April 25, 2009 at 10:27PM
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novice_2009(zone 6b)

Uggg! These gnats are out of control. Sterilizing pots at this point too time-consuming. My potted cilantro not looking good either! If I move them outdoors, will it clear up? Not a fan of pesticides, but I have neem oil, will that help?

    Bookmark   April 26, 2009 at 12:10AM
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ksrogers(EasternMass Z6)

If the infstation was mininal (only a few days until it explodes!) you could sterilize pots and such, but the methods I mentioned work within 5 days and you could be totally rid of them within 2-3 weeks if you have a yellow sticky pads placed at the edge of each pot. The Bt kills only the maggot larve. Spraying the neem, over the soil can help, but many of the bugs either dig into the soil again, or bounce out of the pot. You can actually see this action when watering. Using sterile seed startying medium is very important, and I can't stress enough about the sterile seed starting medium method to prevent the gnats. Depotting and soaking the roots could damage, weaken, and probably kill the tender cilantro roots. The methods I mentioned are 100% organic and quite safe. Bt is a bacteria that attacks the maggots and kills them. The life cycle is shown on one of the links I provided. Nope, moving the plants outdoors will just introduce more gnats to the plants. The gnats are all over my garden right now and can even survive winters. I used beneficial nematodes to reduce their numbers in my garden, and still see them everywhere. The only way to totally eradicate them is to apply the nematodes everywhere (almost impossible), and then followup with Bt. Because they fly, they simply go where they like and lay more eggs. Nasty bug and has destroyed many a commercial greenhouse profit.

    Bookmark   April 26, 2009 at 12:56AM
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Since cilantro is not a long lived plant stop fussing about this pot put it outside or in the trash and plant some more. You should use the BT because the fungus knats have babies in all of your other plants by now. Follow the suggestions above for your future crops.

    Bookmark   April 26, 2009 at 11:13PM
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I kept the soil too moist and since it's Cilantro, I kept it sahde as well. Let the soil dry out and putting it in the sun resolved the issue, but the Cilantro is basical dead now. It couldn't handle the heat and lack of water all at once.

Is it safe to use this pot again? The soil has been buried.
I don't think this will be an issue much longer. I live in AZ and when the heat hits, everything struggles to survive.

    Bookmark   April 27, 2009 at 12:34AM
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ksrogers(EasternMass Z6)

Wash out the pot in hot water with a little bleach before reusing it. Start with STERILE soilless medium. These are made with shreaded coconut husks, with a little perlite added. They have no bugs or diseases so they should not produce the gnats. Obviosly if you have other plants in the same location in pots, they must all be infested with the maggots by now. Allowing the soil to totally dry out only helps a little, as the maggots feed off the roots and roots contain a trace of moisture unless the plants are totally dead. Cilantro does not do well in heat, or sun.

I reuse my 2 inch square pots every year. They are rinsed off in summer when the plants they held were planted outdoors. Then they sit all winter and totally dry out indoors. Then in spring, I rinse them in hot water before they get filled with the soilless mix.

    Bookmark   April 27, 2009 at 4:41AM
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