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Thread: Yet another sundew screwed!

  1. #9

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    The insecticides available in my country end up usually killing both the pests and the plant(I've tried diluting to about 0,05 % and using some. BAM! Instakill! ). So i try to avoid insecticides.

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    Quote Originally Posted by Superplant96 View Post
    The insecticides available in my country end up usually killing both the pests and the plant(I've tried diluting to about 0,05 % and using some. BAM! Instakill! ). So i try to avoid insecticides.
    Very strange.
    What did you use killing the plant, I'm guessing the sales name is not "Instakill"?

    So if you want to give a try to a BTI product instead, I found out how you can get it in your country. Go to the ebay site of your country http://www.ebay.pl/
    Then do a search for "stechmückenfrei".

    You will then find (currently) two offers from German vendors for the product "Neudorff Stechmückenfrei" that are available for delivery to Poland, too. The product is a pure BTI product.

    If you want to use that, just let me know and I can give you additional hints for use against fungus gnats. The product itself comes only with a description how to use it against mosquito larvae in rain barrels and garden ponds. The manufacturer does not tell in its usage instructions that it is intended for fighting fungus gnats.

    And indeed (as I told you above): BTI as in that product may have good or bad results against fungus gnats. This just depends on whether your fungus gnat variety has developed resistance against BTI or not. But your plants are safe, BTI will do absolute no harm to them.

  3. #11
    Hello, I must be going... Not a Number's Avatar
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    Well you leave little alternative other than doing nothing and watch your plants die.

    Then again we haven't actually established the larvae are fungus gnats but your description certainly sounds like they are. And the larvae may be a symptom rather than the cause - dying plants - more dead matter - more food source for fungus gnats.

    Any treatment is weighing the risk to benefit and likely outcome.

    1) Do nothing. Risk - high or none depending on how you want to look at it. Outcome - Dead plants based on previous outcomes.

    2) Repot. Drosera aliciae has a robust root system and are robust plants. You'd eliminate most of the larvae, pupae and eggs, a sand mulch will prevent future infestations. Risk, very little. At the beginning of summer I repotted my 6 year old colony of D. aliciae that was in serious decline. The peat moss was breaking down to the point of gaps forming between the plants. Some crowns had turned brown and apparently died. Flowers had been aborting for the past 3 years. One plant the roots snapped off. I trimmed off the skirts of dead leaves, threw out a couple of "dead" ones and repotted everything else include the rootless one in fresh media. Rootless plant resumed growth after about 6 weeks. Healthiest plants flowered and judging from the seed capsules (just harvested and drying as we speak) seed yield will be spectacular. "Dead" plants sent up 3-5 offshoots with more on the way. I have more growing points now than I began with. Risk - some to very little, outcome - very good.

    3) Hydrogen peroxide. I've never heard of using this to treat fungus gnat larvae. I suspect concentrations high enough to kill larvae won't do the plants much good either. I've used stabilized H202 to treat the soil of sundews before with no deleterious effects. I suppose it depends on the stabilizer, but should easily flushed out media. Risk/outcome - unknown

    4) Bti. As Jesse points out it may or may not be effective, depending on the strain of gnat involved. Risk - very little, outcome - excellent (if it works).

    5) Insecticides. According to you - high risk. Based on experience with compounds generally acknowledged as "safe" (with cautious use), Pyrethrins, neem extracts, Orthene, Imidacloprid (Provado) are effective against the species/genus they are meant for with little deleterious effects to the plants. What usually cause problems are the inactive ingredients, binders and carriers. Products in aerosol cans are particularly suspect due to the nature of the propellants, binders and carriers. Outcome - depends on the insecticide, if it was properly applied and the target organisms.

    6) Sand mulch. Guides that recommend this say to use as a preventative so how effective it is with an active infestation is unknown. However it seems to me if the adults cannot get to layer of peat moss to lay their eggs reinfestation would be less likely. Risk - little to none other than the plants might expire before the "egg" generation pupates. Outcome - questionable due to the active infestation, otherwise very good (gnat free).
    Last edited by Not a Number; 09-14-2011 at 06:12 PM.
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    Your Real Mom ErrorEN's Avatar
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    Pardon my ignorance but is it possible to just drown the fungus gnat larvae? Or is it possible that eggs could survive.

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    i wonder if dry ice and CO2 would work like Ron reported worked for his aphid infestations

  6. #14

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    Looks like i don't have much of a choice. Like i said i'm not going down the insecticide road again. I guess i could try taking the plant out and washing the roots (high chance that i'll damage them) and either disinfect the peat with hydrogen peroxide or like WaterKirby said, nuke it with a microwave. Buying BTI off Ebay, hmm maybe (for future plants if this one goes kaput).
    Guess i'll take the risk and try washing the roots and replanting (In my sitch it's the only reasonable thing i can do).
    As for the insecticide it probably contained some inactive ingredient that killed the plant(generally they are used for treating vegetables, fruit trees and other less delicate plants).

  7. #15
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    Quote Originally Posted by Eric_N View Post
    Pardon my ignorance but is it possible to just drown the fungus gnat larvae? Or is it possible that eggs could survive.
    Drowning fungus gnat larvae works as well as drowning bog plants. If your plants survive drowning, the fungus gnat larvae will do as well. You can drown earthworms in your pots, but not fungus gnat larvae with good success.

    Quote Originally Posted by Superplant96 View Post
    Looks like i don't have much of a choice. Like i said i'm not going down the insecticide road again. I guess i could try taking the plant out and washing the roots (high chance that i'll damage them) and either disinfect the peat with hydrogen peroxide or like WaterKirby said, nuke it with a microwave.
    Repotting into fresh substrate works. But unfortunately, the life cycle of fungus gnats at room temperature is around 28 days. So if you have a general problem with fungus gnats, the problem can return within just four weeks.

    Quote Originally Posted by Superplant96 View Post
    Buying BTI off Ebay, hmm maybe (for future plants if this one goes kaput).
    Yes, ordering from foreign country may be slow and also the effect on BTI comes slow. BTI works best on the smallest larvae you hardly can see. So perhaps the biggest larvae will survive on the first usage of BTI and still develop to flying insects, then BTI will kill the next generation of the next four weeks.

    Quote Originally Posted by Eric_N View Post
    As for the insecticide it probably contained some inactive ingredient that killed the plant(generally they are used for treating vegetables, fruit trees and other less delicate plants).
    There are several hundreds of insecticides available in each country and you cannot use every insecticide against anything you want to fight. If you want to fight caterpillars on apple trees you need a different insecticide than for fighting fungus gnats in a potted substrate.

    And independent of what critters you want to fight: For carnivorous plants that digest insects on their leaves (i.e. Byblis, Drosophyllum, Drosera, Pinguicula) please NEVER use any insecticide for spraying with a formula mixed with some kind of "oil" or "soap" in it! Never ever, this oil and soap will destroy the leaves! With Drosera and Co. you only can use pure "systemic insecticide" with absolutely NO oil ("white oil", "liquid paraffin") or green soap added.

  8. #16

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    Quote Originally Posted by jesse View Post
    For carnivorous plants that digest insects on their leaves (i.e. Byblis, Drosophyllum, Drosera, Pinguicula) please NEVER use any insecticide for spraying with a formula mixed with some kind of "oil" or "soap" in it! Never ever, this oil and soap will destroy the leaves! With Drosera and Co. you only can use pure "systemic insecticide" with absolutely NO oil ("white oil", "liquid paraffin") or green soap added.
    Understood.
    Anyway I simply washed the roots and replanted the sundew. Fingers crossed that it doesn't die!

    Edit: It's been some time and it looks like the sundew survived(Fingers crossed!). What a relief! Thanks for all the info, tips and suggestions, the have been, or at least will be helpful. Also I'm getting those mosquito dunks so the fungus gnat larvae don't stand a chance.

    The thread may now be closed.
    Last edited by Superplant96; 09-28-2011 at 02:19 PM.

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