Bacillus thuringiensis-How focused? How selective?

actionclawJuly 27, 2011

I don't like the idea of using insecticides, pesticides, herbicides ..chemicals of any type, even chemical fertilizers but, because it is supposedly natural, generally benign, etc., I'm considering trying Bacillus thuringiensis to control mosquitoes and certain other BTs to help control other pests.

Are these really as focused to one specific target as they claim?

Will Bacillus thuringiensis, for example, kill Mosquitoes, nothing but Mosquitoes and have no effect on Spiders, Mantises, lacewings, Ladybugs, wasps or other desirable predators?

Willow beetles, for example, are supposedly susceptible to Bacillus thuringiensis but might lady beetles be collateral damage?

Probably my greatest concern is that I have a huge, healthy worm population I do not want to harm.

Is it really a case of "Eliminate the Pest, Safe for the rest"?(Copyright 2011. BT manufacturers, contact me for use, permission and where to send the checks ;) )

Has anyone seen a comprehensive list of specifically what is effected by each BT strain?

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jean001a(Portland OR 7b)

Bacillus thuringiensis israelensis kills Diptera, with mosquitoes the main target; also gets others in the fly family such as midges.

Bacillus thuringiensis kurstaki kills caterpillars, if they eat it before they're half-grown. Can be used on veggies even on the day of harvest.

Bacillus thuringiensis san diego kills beetles of the scarab group. Main target is Japanese beetles. Lady bugs aren't affected.

Worms aren't affected by any of the forms.

    Bookmark   July 27, 2011 at 10:20PM
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rhizo_1 (North AL) zone 7

Bt-israelensis also gets fungus gnats, the horrid biting black fly, and other gnats. It's my 'favorite' strain. ;-)

The answers to your justifiable concerns are just a few mouse clicks away. These products have been used for GENERATIONS. There is an enormous amount of information about it on the internet. Just direct your research to the specific strains of Bt that Jean mentions.

I'm glad you're concerned and you are right to try to collect information BEFORE using such products. Luckily, you should be able to put your mind to rest in a matter of a few moments.

    Bookmark   July 27, 2011 at 11:05PM
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The "Bacillus thuringiensis" bacteriums have been available since the 1950's (not sure about generations) even though these soil dwelling bacteriums have been around forever. This article from Colorado State University might be of some help.

Here is a link that might be useful: About Bacillus thuringiensis

    Bookmark   July 28, 2011 at 7:09AM
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Thanks for the responses/info. That seems to just about cover it. It's a little difficult to believe that it can be so selective. Also that something can, accomplish exactly what we want without suffering other negative consequences. I'm generally somewhat skeptical, of the "If something seems too good to be true.." school but I guess it's so ..and that's great. Between the Israelensis and Kurstaki strains, it seems BT should solve (almost) all my probelms.

(To get only a little off topic, I've already been out shopping for it and, so far, have had no luck. It seems I'll need to go to a garden center the equivelent of a "Mom & Pop" health food store because in the stores I have visited, though there were aisles tall and long fully stocked with a variety of toxic chemicals, pesticides & "wide-spectrum" poisons (real wide; toxic to any and all insects, your cat, dog, kid, you, me...), there was none of this apparently safe but effective BT to be found.

But what they did stock, believe it or not, was speciality bags of "Snake poison" complete with vicious about-to-getcha Rattlesnake on the cover! There are no rattlers, no venomous or, in any way, harmful snakes for hundreds of miles around! (The possible exception being a few in teenage boys' bedroom aquariums.)

This is so back-ass-ward. I can't help but wonder if it's a conspiracy of capitalists knowingly, scheming to "sell more product" no matter what, regardless of the hazards and totally unnecessary negative environmental impact or merely simpletons in management responding to supply and demand and catering to multi-billion dollar chemical manufacturers. If their ignorant customers are afraid of snakes, it's much easier--as well as far more profitable-- to sell them a poisonous solution to allay their fears than to educate and convince them that any snakes in their area are "their friends" willing to eat whatever annoys them. Adding further fuel to the first scenario, fewer beneficial snakes means more pests which translates to higher volume of additional poison sales for them!)

    Bookmark   July 28, 2011 at 10:04PM
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jean001a(Portland OR 7b)

You'll need to read labels.

Bt for caterpillars is sold under a number of different product names, among them these
Attack for Caterpillars

Bt israelensis is sold as Mosquito Dunks and another I don't recall at the moment.

    Bookmark   July 28, 2011 at 10:13PM
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rhizo_1 (North AL) zone 7

Good grief, actionclaw! Bt products have been sold in mainstream garden centers (including the big box stores) for years!

Shed your skeptical skin, and read the darned labels! If you don't feel inclined to do that, you can readily find these products on line.

Also, if you spend just a tiny bit of time reading about how these naturally occurring bacterium strains effect specific species, perhaps you'll gain some confidence.

It is important to mention that the efficacy of any natural Bt application is dependent upon its proper use. If you wish to control mosquitoes, Bt-I is only effective as a must be applied to the standing water that is the source for the mosquitoes. It doesn't effect adult mosquitoes at all.

As for your 'other pests', Bt-K is only effective against YOUNG caterpillars. That's it. It must be applied to the foliage that the caterpillars are devouring.

So, if your pest problems don't fall into these limited categories, you'll be supremely unhappy with the results.

    Bookmark   July 28, 2011 at 11:10PM
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I find that not all garden centers carry and sell any of the "Bacillus thuringiensis" strains and many have never heard of the stuff, or as at one the owner, with a degree in horticulture, will tell you that it does not work and that is why they do not carry it. This being the same person that sold someone the Bayer All Purpose Insecticde to cure a frost problem.
All of the Bt products are effective against the target insect up to certain stages in the life of that insect, knowing what to use, when is part of the Integrated Pest Management program that every gardener should be following.

    Bookmark   July 29, 2011 at 7:03AM
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Dan Staley

Bt is one of the most effective tools the organic gardener has, and with the attempt at using a Bt in a GMO crop, there were many justified fears that big ag eliminated their competitors.

At any rate, not sure why the objection, unless simply analysis paralysis or too much skepticism.


    Bookmark   July 29, 2011 at 10:57AM
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What possibly could have immediately lead one to the (incorrect) conclusion that I didn't read the labels? Do I impress as a careless and illiterate imbecile or do you have that much confidence in your "big box stores"?

Obviously, it is sold by some garden centers and "big box stores" and I don't doubt that yours is one of them. Why is it so hard to believe that some simply don't carry it? (I could optimistically believe that they do, it's selling like hotcakes and they're all sold out!) What would cause you to immediately assume, instead, that I must not have looked hard enough or didn't read the labels? (Feel free to print out this post and use it as sufficient grounds to excuse you from jury duty.)

After a cursory scan of the selection in the outdoor section that immediately turned up nothing I headed directly to the large indoor aisle(s) where I actually expected it to be found. I fully expected to find it so continued to look until I did: not only in with gardening but even in lawns, houseplants, etc. After a more thorough check of these, surprised to find nothing I returned to those outdoors for a more comprehensive inspection. Having already spent more time than I cared to, as I was about give up and leave a violent thunderstorm erupted outdoors encouraging me to stay long enough to repeat the process in both areas in case I may have overlooked anything.

Of course, I read the labels.

No, not "in their entirety" as that would have required the remainder of the day (or two) and probably a fairly strong magnifying glass. I considered it sufficient to read enough so that if I did not see anything that indicated BT in any form, be it "BT", "bacillus thuringiensis", "biological insecticides" or similar but I did see as active ingredients carbamates, tralomethrin, allethrin, prallethrin, lambda cyhalothrin, pyrethrins ..or any of the other "-ethrin"s, I could stop reading that one and move on to the next. ("Thuricide", I was unaware of and must admit that, had I seen it, I probably would have passed).

    Bookmark   July 29, 2011 at 1:24PM
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Dan Staley


    Bookmark   July 29, 2011 at 4:53PM
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actionclaw, please continue to question (and find the answers) to your enquiries. Here are a few of my tenets.

  1. Every chemical is designed to take care of a particular problem but its label might not indicate that.
    I once applied a PGR to St. Augustine grass in complete compliance with its label. The turf paled out to an unacceptable degree for my liking. I had to go all the way back to the R & D personnel to find out that the product was designed to prevent seedhead development on Bahia turf.I later applied it for that purpose and it worked like a charm. The anectodal biography of 'Round-Up' has many fascinating versions. One version has it that that the weedkiller started life as a radiator flush!
  2. The label does not have all the answers.
    Because if it did, we would not be advised to "test on a small area".
  3. Some formulations of a product can have properties which are different from what have been traditionally held.
    Pyrethrin has been morphed into pyrethroids which themselves have been tweaked to make them more long lasting. There is an irony here. Pyrethrin, a very short term product was touted to replace the long lasting Organo-Phosphates; now these same replacements are being tweaked to make them more long lasting.
    Let me emphasize that I have practiced IPM since it was IC (Integrated Control). I use chemicals. I retain a healthy respect for the research that goes into the development of chemicals and the Agencies that seek to regulate their use. My greatest concern is the end-user. I have bought and sold chemicals. I am still frightened by the pervasive unwillingness to read the label
    Bookmark   July 30, 2011 at 7:16AM
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dvdgzmn(Sunset 17 SF CA)

In addition to the ones listed above, BT is sold as Safer brand Caterpillar Killer. The label says it's species kurstaki, so don't expect it to kill anything else. It seems to be harder to find recently. This year Lowes did not have it under any name, but the independent garden center across the street did.

It's not so odd that bacteria can be so selective in killing bugs if you think about it. One species of bacillus bordetella causes whooping cough in humans and another has no effect on humans but causes kennel cough in dogs. Yet another species causes some disease in pigs (I never had a pig, so you'll have to look it up if you're interested).

    Bookmark   July 30, 2011 at 4:51PM
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"Bacillus" is a word that describes a wide range of rod shaped bacteria. It is a pretty general term with a very large and diverse list of bacteria in its column, just as Bacteria describes many very small thingys many of which we need to survive but some of which can cause disease. Bacteria can live outside the body while viruses cannot not.

    Bookmark   August 1, 2011 at 7:07AM
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kimmsr...Are you positive that last statement is true? I'm pretty sure it's incorrect...cold and flu viruses can and do thrive outside the body.

    Bookmark   August 1, 2011 at 9:36PM
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Not according to the Center for Disease control or the National Institute for Health. If viruses can thrive outside the body that information they supplied me that I use when teaching Bloodborne Pathogen classes has been wrong for 15 years.

    Bookmark   August 2, 2011 at 6:23AM
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Are you guys conversing off the same platform?
You appear to be using terms interchangeably and I am not sure that it makes for a good scientific discourse.
Bacteria vs. viruses.
Survive vs. thrive.
An opinion only.

    Bookmark   August 2, 2011 at 7:05AM
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