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Thread: Fungus Gnats

  1. #1
    Join Date
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    Fungus Gnats

    Anyone ever had a problem with something called fungus gnats? One of our members is apparently having a problem, and I wondered if any of you have ever dealt with this problem?

    It is new to me, so I can't really help....
    Ann B.
    Zone 9a
    Gulf Coast


  2. #2
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    Center Point, TX
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    Post Fungus gnats

    Go to http://ohioline.osu.edu/hyg-fact/2000/2114.html for more info. Kill them with a harmless pyrethrin spray. Use sterile potting media to prevent.

  3. #3
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    Suffolk County, LI - NY
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    Talking

    I had a swarm of these gnats not too long ago. I bought Shultz' Expert Gardener insect spray for houseplants and sprayed every plant I had. In minutes, no more gnats. Several days later, I still do not see any.

    TomG. - aka Plant_Guy

  4. #4
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    Feb 2002
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    Milwaukee, WI
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    Hi Ann,

    I didn't think these would be a problem in "natural" gardening.

    I had a terrible problem with them when I was doing aquaponics. Every breath you took, you got them in your mouth, up your nose and just about every other orifice you could think of.

    The gnat, in itself, is not a problem... a nuisance but not a problem. BUT!! The gnat is an adult. The problem is with the babies. They kind of look like a mosquito larvae and they will attack and eat the root of whatever it is that you have growing. There is a product called Gnatrol that will quite effectively control the larvae. Control the larvae and you will control the gnat.

    But, have the person who is having problems research on their search engine fungus gnat, gnatrol, etc. for there is quite a huge difference in price of some of the products. I bought Gnatrol and found it to be quite effective.

    Steve

  5. #5
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    Here's another indoor spoiler

    After reviving the damping off disease thread, I decided to search on damping off disease on the internet and ran into another arch villain--the fungus gnat. That led me back to another search and another good previous thread on Landspro. I never knew what they were called but just that sometimes I get little black flies buzzing around plants or sometimes water faucets. I figured they were some how connected to plants and dampness but didn't know they were nogoodniks. Well, they too are not conducive to seedling starting. I suspect my vectors are 2 spider plants that spent summer outdoors and were just whisked indoors without removing dead tree leaves, etc. Well, at least I'm realizing more things this year

    Below is a copy and paste from the internet:

    These tiny, black insects seem innocuous enough as they buzz over your plants. While the adults rarely cause any problems to plants, if the young larvae are in large numbers, they can damage your seedlings. Fungus gnats search out moist soil in which to lay their eggs. When the eggs hatch, the larvae will feed on the roots of your plants. Healthy seedlings will often be able to withstand this feeding but any seedlings that have small root systems like onions and leeks and those that are showing symptoms of nutrient stress can be put back quite significantly.

    The easiest way to prevent fungus gnats is to water your plants properly. Overwatering, which causes your potting mix to remain moist for extended periods of time, seems to attract fungus gnats. If your plants are already infected, allow the soil to dry out between watering. Alternatively, sprinkle a " of sand on top of your soil to confuse the adults. Since the sand drains water quickly, it can sometimes trick the adults into thinking the soil is dry.

    Potting mixes containing peat seem to be particularly affected by fungus gnats. If the problem is reoccurring for you, think about switching from a peat-based mix to one that only contains perlite and vermiculite. Lastly, if the adult fungus gnats are bothersome, trap them by making your own sticky trap. The adults are attracted to the color yellow. Make your own sticky trap by smearing Vaseline or Tanglefoot on a yellow surface and hang it up close to where the adults congregate.
    Last edited by Dazed_Lily; 01-09-2004 at 07:11 PM.
    "If I keep a green bough in my heart, a singing bird will come"




  6. #6
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    This is the first year that I have ever spotted them. There weren't very many, but enough to make me concerned.

    This is also the first year that I did not soak my peat moss in boiling water. Some my laugh at that approach, but from now on my seedling mix will receive a very HOT bath.

    You see, I use the big packages of peat to make my own seed mix. Once opened, it is subjected to whatever decides to make a home there.

    I guess if boiling water works for me, it simply works for me. I am not real keen on the idea of putting peat in my microwave or oven, but I am told that also works.

    But I even hate the idea of having those bugs near my seedlings or cuttings even worse!
    Ann B.
    Zone 9a
    Gulf Coast


  7. #7
    Join Date
    Jun 2006
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    In Chalmette, Louisiana. ZONE 9
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    Mixing a "Mosquito Dunk" in your water will kill the maggot of the fungus gnat. We had a horrible infestation of these disgusting critters.

    All my potted amaryllis plants (about 40) and my seed flats, get watered from a bucket with doughnut-shaped "Mosquito Dunks" dissolved in it. Remember that dunks are used according to the amount of square feet of surface area in your pots and flats. One dunk will treat 1-5 square feet. The Bt stays near the surface and lasts for at least 30 days. It is effective only when wet. I have never seen any fungus gnats since using dunks.

    A typical black nursery-3-gallon pot has about 78 square INCHES of surface area at the top. Which is a little more than half of a square foot.

    The active ingredient is a bacteria of some kind that causes the gut of the maggot to rupture. BT is harmless to humans, plants and non-insect pets.
    He has given me a peace that transcends all understanding!

  8. #8
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    Ray, That was interesting. I would never have thought of that. I had more of a problem in the greenhouse that I do growing out of doors. May be the difference in the watering as I water less often than some people do. I try to let things dry a little before I water, not just water whether they need it or not. Epsecially the gallon pots don't dry out as quickly.
    Now what about those little fuzzy white things that fly around looking like cotton lint? I've killed several today. They are bad guys aren't they?
    tennessee sue

  9. #9
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    I haven't found anything online to support this, but I used a spray bottle with 1/2 water, 1/2 hydrogen peroxide (medicinal) and the moss and fungus knats disappeared from my flats and this didn't seem to bother the seedlings at all. I have been cautious about recommending it, but so far, I haven't killed any plants, just moss and pests...........Cheap, easy.

    I also pour boiling water into my potting soil when I first get ready to stick cuttings. I swish the cuttings in a dribble of chlorox in a large pan of water and rinse them off i running water before I dip them in the rooting hormone and stick them in the (now cooled) potting soil. seems to work fine.
    Linda
    Linda

  10. #10
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    Apr 2006
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    Duesseldorf/Germany
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    Peat based substrates are principally dodgy of being contaminated with these potentially fatal maggots of this little fly. Because the plastic bags are not hermetically closed or /and damaged and often they are shelved in the garden center for a prolonged time
    A treatment in the microwave oven is also helpfull then.

    One fungus gnat dame is capable of laying up to 200 eggs in its short life, and she will distribute these carefully in aliquots of 20-30 over the substrate area.

    I cover my seed beds with a granulate which permanently releases its agent chlorpyriphos over 2-3 months. In Germany the brand is "Nexion Neu" from Celaflor, alternatively "Ridder" from Bayer, and I guess that in certain transatlantic countries (as viewed from my German stand point) "Dursban solid" from DOW might be available - but it cannot be excluded, that Chlorpyriphos be (already) banned in some of these countries.
    A granulate which contains the systemic agent Imidacloprid should work very well, too, for example Lizetan-Kombigranulat...
    Last edited by haweha; 07-14-2006 at 09:10 AM.

  11. #11
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    Thanks, Hans!

    I definitely have some learning to do when it comes to pesticides. If we have another year like this one, I need to figure out a way to rid of those horrid grasshoppers without harming my beneficials.

    Several times, I have spotted a baby praying mantis in my greenhouse. He was very tiny the first time, about an inch. This last time, he is about 1.5 inches long. He comes out to check things out when I turn on the cool mist system.

    It's really funny to watch him. Sometimes, he wants to climb on my fingers and sometimes he doesn't. I suppose he just wants to prowl.

    Hans, since you are a biologist and understand all these chemical names, please keep us posted if you see brand names associated with these insecticides AND are available to the home user.

    So many things are being banned from use by anyone that is not licensed to use them, and I do understand that is because of misuse by the less knowledgeable.

    BTW, IF I can, I will try to get a picture of my baby praying mantis. He is way too COOL! And NOPE, I don't know for sure that it is a HE, but for now, that will do...

    Thanks, Hans, for the knowledge you so graciously share!
    Ann B.
    Zone 9a
    Gulf Coast


  12. #12
    Join Date
    Feb 2002
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    Spectracide 7000 Dursban Granules contains chlorpyrifos

    Those big grasshoppers are easiest to control in early summer/late spring when they are small. The will not hurt you, so just pic them off and step on them. However, they do sometimes produce a toxic liquid that may make you sick if it gets on your hands and then on your food, so wash hands or use gloves.
    Tom W
    Aching Back Farm

  13. #13
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    Thanks, Hans! Thanks, Tom!

    Pardon my slowness. Sometimes, it takes a while to sink in...
    Ann B.
    Zone 9a
    Gulf Coast


  14. #14
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    Don't know why I missed this post earlier, but anyway. . . . you can determine the sex of mantids by their color, even the very small ones! Males are tan to brown while the females are always green! Isn't that just amazing!

    As you know, I maintain a large "heard" of mantids throughout my various flower beds and seldom see very many males as they stay hidden until mating season, but I do have a lot of females! I've also been noticing quite a few very tinys ones just in the last couple of days. Appearently more eggs have been hatching out as the season has progressed and more food is available. I am hoping for a bumper crop of frothy egg cases this fall and if anyone needs any for their gardens just let me know and I might be about to send a few to you in late fall.




    Rebecca
    Nature is trying very hard to make us succeed, but nature does not depend on us. We are not the only experiment.
    - R. Buckminster Fuller

  15. #15
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    northeast Tennessee
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    I've seen a couple of more mantis in the last few days. Mine are all girls so far!
    tennessee sue

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