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Re: BT

Square Foot Gardening List - http://www.flinet.com/~gallus/sqft.html

Hi Janet,

Here's the lead in from the PESTIS article on Bt:

Swadener. Journal of Pesticide Reform,
Volume 14, Number 3, Fall 1994.
Northwest Coalition for Alternatives to Pesticides,
Eugene, OR.

Bacillus thuringiensis (B.t.)
by Carrie Swadener

Introduction

Bacillus thuringiensis (B.t.) is a live microorganism that
kills certain insects and is used to kill unwanted insects in
forests, agriculture, and urban areas.
In a purified form, some of the proteins produced by B.t. are
acutely toxic to mammals. However, in their natural form,
acute toxicity of commonly-used  B.t. varieties is limited to
caterpillars, mosquito larvae, and beetle larvae. B.t. is
closely related to B. cereus, a bacteria that causes food
poisoning and to B. anthracis, the agent of the disease
anthrax. Few studies have been conducted on the chronic
health effects, carcinogenicity, or mutagenicity of B.t.
People exposed to B.t. have complained of respiratory, eye,
and skin irritation, and one corneal ulcer has occurred after
direct contact with a B.t. formulation. People also suffer
from allergies to the "inert" (secret) ingredients. People
with compromised immune systems may be particularly susceptible to B.t.
Viable B.t. spores are known to exist for up to one year
following application. Insect resistance to B.t. has been
well documented. Genetic engineering may greatly expand use
of B.t., speeding up the development of more resistance.
Large-scale applications of B.t. can have far-reaching
ecological impacts. B.t. can reduce dramatically the number
and variety of moth and butterfly species, which in turn
impacts birds and mammals that feed on caterpillars. In
addition, a number of beneficial insects are adversely impacted by B.t.
B.t. is less toxic to mammals and shows fewer environmental
effects than many synthetic insecticides. However, this is no
reason to use it indiscriminately. Its environmental and
health effects as well as those of all other alternatives
must be thoroughly considered before use. B.t. should be used
only when necessary, and in the smallest quantities possible.
It should always be used as part of a sustainable management program.

********************************************************

This article is found at :
gopher://gopher.igc.apc.org:2998/0PESTIS/r.930923910.16028.25

And can be reached thru the PANUPS website, http://www.panna.org

The full article is extensively footnoted.

FYI,

Frank---who uses Bt carefully in some of his brassiculture...

-----Original Message-----
From: Janet Wintermute <jwintermute@erols.com>
To: sqft@listbot.com <sqft@listbot.com>
Date: Thursday, July 01, 1999 2:39 PM
Subject: Re: BT


>Square Foot Gardening List - http://www.flinet.com/~gallus/sqft.html
>
>Bonnie Christensen, posting from Utah, is concerned about the safety of
>Bacillus thuringiensis (Bt):
>>I just purchased some BT for the first time and I'm afraid to use it.  The
>>lable says that it is very dangerous to use.  Can anyone please tell me
how
>>they use it safely and is it as dangerous as the company that makes it
seems
>>to think it is?
>
>I am astonished to hear that any producer of Bt would make a label
statement
>that it is "very dangerous."  It is NOT very dangerous, or even plain
>"dangerous" to use!  Recent posts concerning possible dangers of inhaling
Bt
>constitute the first mention I have ever seen that it has ANY effect on
>mammals at all.  (And those sounded quite anecdotal....)
>
>I can assure you that if it were dangerous to apply, the U.S. Environmental
>Protection Agency would not have labeled it for over-the-counter sale and
>application by ordinary folks.  Pesticide products that are "dangerous" for
>people to handle must be applied by certified pesticide
>applicators--individuals who have passed tests on safe handling practices
so
>they do not unnecessarily risk their own health.
>
>Remember, Bt is a naturally occurring bacterium--not a
petrochemical-derived
>poison.
>
>Bonnie, please tell me what brand of Bt you have and please post the exact
>wording from the label.  I just can't believe a company would shoot its own
>product in the foot in the way you describe!
>
>Perhaps you are reacting to the canned boilerplate language that says,
>roughly, "It is against Federal law to use this product in ways that are
not
>specifically approved on this label."
>
>*That* language is part of a prepared statement from EPA on all pesticide
>containers, not just Bt.  It's a warning against (1) applying XYZ to pests
>or crops for which it has not been proven safe and effective, and (2)
mixing
>up batches in any old proportion you feel OK about, regardless of what the
>label told you to do in terms of amount of active ingredients.
>
>One of my favorite USDA business pals is Homer Collins, fire ant scientist
>at our Gulfport, MS, lab.  Homer was around in the 1950's, when, he tells
>me, everybody was spraying DDT on fields for fire-ant and other pest
control
>at rates of POUNDS (plural) per acre.  EPA came into existence and put a
>stop to all that.  Currently, for most pesticides, the labeled levels of
>active ingredient are under 1 oz/acre, and sometimes *way* under (a
>testimonial to how powerful some of these chemicals are, for sure).
>
>--Janet
>
>
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