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  1. #1
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    Default BT Bacillus thuringiensis not trouble free

    Effect of Larvae Treated with Mixed Biopesticide Bacillus thuringiensis - Abamectin on Sex Pheromone Communication System in Cotton Bollworm, Helicoverpa armigera
    Biopesticide usage is increasing every year, even more with the prespective that mixtures of pesticides are theoretically more effective in delaying resistance than alternating usage of pesticides [24]. An example of this strategy is the conjugation of the toxins from Bacillus thuringiensis with the toxin of abamectin, to form a new biopesticide called BtA [25]. This BtA mixture has been widely used to control agricultural pests [26][28] and the usage of BtA was in the hundreds of tons in several provinces of China in 2011. Many researchers have demonstrated that pesticides impact natural enemies directly or indirectly [4][11]. The longevity of Microplitis mediator, a parasitoid of the cotton bollworm (Helicoverpa armigera) decreased significantly after being fed with 10% honey water containing a sublethal dose of a Bacillus thuringiensis and abamectin (BtA) [10].
    http://www.plosone.org/article/info%...l.pone.0068756
    americasbeekeeper.com
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  2. #2
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    Default Re: BT Bacillus thuringiensis not trouble free

    So what does this study mean for bees and beekeepers?
    --shinbone
    (3rd year, 14 hives, Zone 5b, 5400 ft, 15.8" annual rainfall)

  3. #3
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    Default Re: BT Bacillus thuringiensis not trouble free

    Insects with a larval stage, like bees, can be weakened and can be killed when Bt is present. It usually goes unnoticed since it is the larval stage. Bees are insects too.
    americasbeekeeper.com
    beekeeper@americasbeekeeper.com

  4. #4
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    Default Re: BT Bacillus thuringiensis not trouble free

    Sorry, I am not seeing the connection. Cotton bollworm moths lay their eggs on the cotton plant, the hatched larvae eat the cotton leaves, and pupate in the soil. As you know, bees start as eggs inside a cell inside a hive and pupate there as well. It seems a bee's exposure potential to Bt is completely different than a cotton bollworm's exposure to Bt. How can you say that Bt will weaken and kill bees based on how it affects an organism with a substantially different life cycle?
    --shinbone
    (3rd year, 14 hives, Zone 5b, 5400 ft, 15.8" annual rainfall)

  5. #5
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    Default Re: BT Bacillus thuringiensis not trouble free

    Shinbone, BT is used by some beekeepers on their stored combs as an off-label treatment against wax moths.

  6. #6
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    Default Re: BT Bacillus thuringiensis not trouble free

    Adrian - Okay. Thanks.

    The abstract AmericasBeekeeper cryptically posted is about the combination of Bt and Abamectin. Beekeepers use just Bt by itself for controlling wax moth on stored comb. I still am not seeing a connection between the posted abstract and beekeepers.
    --shinbone
    (3rd year, 14 hives, Zone 5b, 5400 ft, 15.8" annual rainfall)

  7. #7
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    Default Re: BT Bacillus thuringiensis not trouble free

    True but bees bring in pesticides, fungicides, and antibiotics when they forage, even in the middle of organic farms. The combination of compounds is what is hurting them. Take a moment to read the National Honey Bee Survey. It is amazing what bees bring home and occasionally what beekeepers pour in the hives.
    americasbeekeeper.com
    beekeeper@americasbeekeeper.com

  8. #8
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    Default Re: BT Bacillus thuringiensis not trouble free

    From what I have been hearing this summer it sounds like a lot of the backyard "organic" gardeners have been using Bt in some form to treat just about everything. Local farm supply has been selling a lot of it. That does concern me as not everyone reads or follows directions. "if a little bit works, a lot must work even better".

  9. #9
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    Default Re: BT Bacillus thuringiensis not trouble free

    Perhaps they do not realize that a biopesticide is still a PESTICIDE!
    americasbeekeeper.com
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  10. #10
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    Default Re: BT Bacillus thuringiensis not trouble free

    Quote Originally Posted by AmericasBeekeeper View Post
    Perhaps they do not realize that a biopesticide is still a PESTICIDE!
    Most do not have a clue especially when it comes to anything labeled "organic". I know one guy who bought BT at the feed store to treat an insect it is not labeled for and may not have any effect on. He "figured it was safe, so just have to use more of it to kill the little buggers". He bought it because "it wasn't made by one of them chemical giants", I think he meant Monsanto but again he doesn't likely have a clue what they sell.

  11. #11
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    Default Re: BT Bacillus thuringiensis not trouble free

    Unless we wish to starve to death in the dark in a cave, we are going use a number of things to make a living upon the land which our Lord God gave us. Bt is a bacillus, nothing more, that attacks the larvae of moths if they are present. You might be able to smother something else if you poured enough of it on them, but the bacillus will not attack them if they are not tasty. Robins do not eat lettuce because it is available. Tigers cannot live on eggplant, ergo------Being rational and knowledgeable about the effects of things and not just responding in a knee jerk manner is always beneficial.

  12. #12
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    Default Re: BT Bacillus thuringiensis not trouble free

    Quote Originally Posted by AmericasBeekeeper View Post
    True but bees bring in pesticides, fungicides, and antibiotics when they forage, even in the middle of organic farms. The combination of compounds is what is hurting them. Take a moment to read the National Honey Bee Survey. It is amazing what bees bring home and occasionally what beekeepers pour in the hives.
    Occasionally? Is there anything the bees are bringing in in the quantitis/frequencies of beekeeper applied pesticides? Are the levels of beekeeper applied pesticides found in hives consistente with application of legal on label use of approved substances by beekeepers?
    The perils of benefactors; The blessings of parasites; Blindness blindness and sight -Joni Mitchell 'Shadows and Light'

  13. #13
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    Default Re: BT Bacillus thuringiensis not trouble free

    Quote Originally Posted by AmericasBeekeeper View Post
    Insects with a larval stage, like bees, can be weakened and can be killed when Bt is present. It usually goes unnoticed since it is the larval stage. Bees are insects too.
    This is not an accurate summary.
    If i can show that drinking orange juice and eating rat poison together is harmful, it does not follow that orange juice is harmful.
    The perils of benefactors; The blessings of parasites; Blindness blindness and sight -Joni Mitchell 'Shadows and Light'

  14. #14
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    Default Re: BT Bacillus thuringiensis not trouble free

    Quote Originally Posted by coopermaple View Post
    From what I have been hearing this summer it sounds like a lot of the backyard "organic" gardeners have been using Bt in some form to treat just about everything. Local farm supply has been selling a lot of it. That does concern me as not everyone reads or follows directions. "if a little bit works, a lot must work even better".
    Bt has been used for decades by organic farmers and gardeners but it isn't something that they use to treat "just about everything" considering that it is only effective against specific stages of juvenile insects such as caterpillars.

    Quote Originally Posted by coopermaple View Post
    Most do not have a clue especially when it comes to anything labeled "organic". I know one guy who bought BT at the feed store to treat an insect it is not labeled for and may not have any effect on. He "figured it was safe, so just have to use more of it to kill the little buggers". He bought it because "it wasn't made by one of them chemical giants", I think he meant Monsanto but again he doesn't likely have a clue what they sell.
    There is concern over the "chemical giants" who have inserted Bt genetics directly into crops such as corn; which does result in effectively treating "just about everything" indiscriminately and increases the likelihood of insect pests becoming resistant.

    Quote Originally Posted by AmericasBeekeeper View Post
    Insects with a larval stage, like bees, can be weakened and can be killed when Bt is present. It usually goes unnoticed since it is the larval stage. Bees are insects too.
    I have been considering using Bt on empty combs but wonder if there is any risk to honeybee larvae that later come into contact with any residues. I believe Bt has a relatively short life in the field and breaks down quickly with exposure to sunlight, rain, etc. so hopefully there would not be much residue left on the combs after storage.

  15. #15
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    Default Re: BT Bacillus thuringiensis not trouble free

    Abamectin is toxic to bees not Bt.

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