Index Home About Blog
From: David Kendra <>
Newsgroups: sci.agriculture,alt.agriculture.misc,alt.sustainable.agriculture
Subject: Re: Ladybug, quickly fly away home!
Date: Sat, 25 Oct 1997 21:26:20 -0500

Rex Harrill wrote:
> A sad aside to all this is that the ladybugs will still be getting
> whacked after the pests quickly develop immunity to the transplanted Bt
> gene.

Does Bt affect ladybugs?  I was unaware of that.  I thought that the
marketed bt products were only active against lepodopteran insects.
Please provide a reference for your claim.  I would like to read it.

> Here is a note snipped from
> that pretty much spells it out.

This document is very outdated and conatains several factual errors.

> ----------------------------------------
> From the Editor s Desk
>           Why UCS Resists Bt Crops
> (snip)
>  Bt, usually delivered in spray form, is remarkable among pesticides for its
>  ability to kill economically important insect pests without harming most
>  other organisms.

What non-insect pests does Bt harm?  I am unaware that it harms any
insect except the target pest.

>  Despite its environmental benefits, Bt has not been widely used in
>  agriculture because the toxin is relatively slow-acting and breaks
>  down in the environment, making it tricky to manage in the field.

Isn't this a good trait?  I thought organic farmers want a non-toxic,
organically benign pesticide.  Have I missed something?

>  Insect resistance to Bt was not observed until the mid-1980s, when scientists
>  reported resistant insects living in grain storage facilities.

Please provide a reference from a scientific publication for this

>  This hypothesis was supported by later studies in Hawaii showing that the
>  diamondback moth developed resistance to Bt where vegetable growers repeatedly
>  applied Bt sprays.1

The Bt was used at excessive rates.  Had farmers followed the
instructions on the label resistance probalbly would not have
developed.  Also,I thought these observations were from laboratory
studies?  Anyone have more info. on this claim?

>  Because the Bt toxin is produced in the tissues of the plants, it is
>  protected from the environment and does not break down.

Not true.  The Bt toxin acts like any protein in the plant an is
remobilized by the plant if not used to kill an insect pest.  I am most
familiar with maize so I will limit my comments to this crop.  In maize,
the Bt gene is constitutively expressed in all plant tissues (except the
Novartis Maximizer hybrids where the gene is expressed only in green
tissues).  Since the gene is turned on all the time the bt protein must
undergo normal degradation in the plant otherwise it would be the only
protein in the cells!

>  Under these conditions, pests feeding on the crops are exposed to
>  high levels of toxin continuously over the life cycle of the crops.

Because the gene is constitutively expressed NOT because the Bt protein
"does not break down".

>  No better recipe could be found for eliciting resistance.

Wrong,  failing to follow instructions for any insecticidal chemical is
the best recipe for developing resistance.

> Some scientists have estimated the life span of Bt used in some
> major crops like cotton, corn, and potato could be as short as
> two to three years.2

Bt maize have been field tested since the early 1990's and doomsday
hasn't yet happened.  This estimate needs to be revised and based on
science not on specualtion.

> There is no plan to address resistance. Bt resistance is
> an old issue in the biotechnology debate. Aware of the
> problem, industry and the government set up working groups to address
> the issue.

The first sentence doesn't make sense after reading the second.  Is
there or isn't there a resistance management plan?  The bottomline is
that industry and government personnel have developed a well thought out
and manageable resistance management plan.  We are aware that someday
resistance will develop to Bt and we want to make sure that is very far
in the future.

>  Theoretically, resistance can be avoided in a number of
>  ways, and early on many expected that the problem could be
>  relatively easily solved. Unfortunately, for both scientific and
>  political reasons, none of the approaches has worked out.

This is news to me.  Please provide evidence to support this claim.

>  Although EPA has encouraged individual companies to submit
>  resistance management plans for use in conjunction with their
>  products, these have been criticized for flawed analyses
>  leading to an understatement of the problem3 or lack of detailed
>  workable strategies.4

Please provide the references listed in the document.  Are the
references from scientifically referred journals?

>  The bottom line is that despite years of discussion and many good ideas, neither
>  government nor industry has advanced a practical comprehensive plan for general
>  avoidance of resistance to Bt.

Please provide evidence for this claim.  Novartis was not allowed to
sell it's Bt11 maize until it provided a very detailed resistance
management plan.  This document was independently reviewed by leading
university and USDA scientists.  Based on the claims made in this
article should I assume that these individuals are scientifically
incompetent since they concluded that the Novartis resistance management
protocol was feasible and would work as developed?

>  With the problems that have been encountered by Calgene with its Flavr Savr tomato

I thought Calgene's problems were due to the fact that the tomatoes
tasted like crap.  The ones I ate did!

Thanks for the article Rex.  I enjoyed reading it.


Dave Kendra

From: (Tracy Aquilla)
Newsgroups: sci.agriculture,alt.agriculture.misc,alt.sustainable.agriculture
Subject: Re: Ladybug, quickly fly away home!
Date: Wed, 29 Oct 97 01:38:53 GMT

In Article <>, Rex Harrill <> wrote:
>David Kendra wrote in response to a Rex Harrill posting [snip]:
>> Does Bt affect ladybugs?  I was unaware of that.  I thought that the
>> marketed bt products were only active against lepodopteran insects.

What about Btt? It is toxic to larvae and adult beetles of Leptinotarsa,
probably other Chrysomelids, and possibly other coleopterans. However, I
have seen no data to suggest that it is active in Coccinellids.

>> Please provide a reference for your claim.  I would like to read it.
>> Thanks.

Those data have not been published. If the article ever passes peer-review,
the data will become available. Don't hold your breath.

>>Bacillus Thuringiensis produces a crystalline toxin that under alkaline
>>conditions and in the presence of specific enzymes dissolves and
>>attacks the stomach wall of a caterpillar and decomposes the enzymes which
>>protect it from the digestive juices.

Bt produces a vast array of toxins, some of which are proteinaceous and form
parasporal crystals. These are the delta-endotoxins, and are the best known.
There are literally hundreds of these toxins, and the range of activities is
great. Some are active against the immature forms of lepidopterans only,
others are active against immature Lepidoptera and Diptera, others against
immature Diptera only, and still others against both immature and adult
Coleoptera. New delta-endotoxins are still being discovered. Recently, new
toxins have been isolated which are toxic to nematodes, and others against

Delta-endotoxins do not decompose enzymes. The toxin activates the integral
sodium-potassium ATPase of the peritrophic membrane, causing acidosis of the
mid-gut, which results in severe feeding inhibition (a belly-ache for the
insect) and eventual death.

Bt also produces other toxins, some of which are very potent and active
against  mammals (eg. beta exotoxin, cytolytic protein, etc.)  Recently, an
enterotoxin (i.e. toxic to E. coli in your intestine) has been found, which
is quite common in the strains used in agriculture. This presents a
potential public health issue which has received almost no attention.

>>I do not know about experiments, for example, in vitro, on the effect of
>>dissolved BT protein toxins on aphids or other sucking insects.
>>Any suggestions?

Did you do a literature search? Currently, there are no known Bt toxins that
are effective against aphids, or any other insects with sucking mouth-parts.
But the person who finds the first one (if ever) will become instantly
famous (among the Bt crowd anyway).

>GE convert, but I'm not yet convinced you would simply ignore data
>because it is contrary to your job, education, and experiences to date.

'GE convert', eh (why the name-calling, Rex)? How can anyone ignore data
which are not available to the public, which they have never seen?

From: (Tracy Aquilla)
Newsgroups: sci.agriculture
Subject: Re: Farming - How Much Acreage Necessary?
Date: Wed, 4 Feb 98 16:06:45 GMT

In Article <>, Rex Harrill <> wrote:
>Craig---I found the Bt article and have recopied it here.
>Communities also now face the loss of safe Bt control of mosquitoes and

No, no, no. This is absolutely false, and particularly exemplifies that the
author is entirely unfamiliar with the nature of the various Bt
formulations, especially the differences between the toxins used in these

Bt-israelensis (Bti) is used world-wide by the World Health Organization
(WHO) to control mosquitoes and blackflies, which are vectors of tropical
diseases that kill millions of people in developing countries every year
(malaria alone kills millions). The toxins in Bti are specific for dipteran
species (flies and mosquitoes).

OTOH, the toxins engineered into Bt-crops are specific for the larvae of
lepidopterans (cutworms and loopers), or coleopterans (potato beetles),
depending on the crop. Mosquitoes and blackflies cannot develop resistance
to the toxins engineered into Bt crops, even if they were somehow exposed to
the crops. In fact, the larvae of mosquitoes and blackflies live in the
water, and hence they never come into contact with crops. Furthermore, adult
mosquitoes and blackflies are not susceptible to Bt toxins (even Bti), and
in particular are not susceptible to the toxins that have been engineered
into crops (not even the larvae). Even if they were susceptible, they do not
eat plants, so they cannot be exposed to these toxins.

Therefore, the selective pressure on mosquitoes and blackflies from Bt crops
is zero. Even if lepidopteran larvae develop resistance to Bt crops, Bti
will still be useful for controlling vectors of tropical disease.

From: (Tracy Aquilla)
Newsgroups: misc.survivalism,misc.rural,sci.agriculture,
Subject: BT resistance...(was Re: Pesticide Problems)
Date: Sun, 1 Mar 98 02:07:52 GMT

In Article <>, (j) wrote:
>back@ya& (Wicked Wild) wrote:
>>David Kendra <> wrote:
>>>I believe the resistance arose from Bt sprays not transgenics.
>>Are you claiming it couldn't have arisen from transgenics?

Possible perhaps, if Bt-plants had existed and had been grown in the field
prior to the time resistance was reported. But that is not the case, and
anyway, how many reports of field resistance to Bt have been published since
transgenic plants were first extensively field tested? None that I know of.
The two documented cases precede the availability of Bt-plants.

>   Initial reports of BT resistance were from spray/dust
>   formulations.

So far, it is only the abuse of conventional Bt formulations that has been
correlated to the two published reports of field resistance.

>   Transgenic BT-producing crops are a rather
>   new phemomena.

Well I suppose, if you consider 15 years old to be 'rather new'. Bt was
first cloned into plants in 1983, and many of these plants have since been
tested quite extensively. However, there have been no published reports of
field resistance resulting from Bt-plants.

>   Unfortunately, the transgenic crops are
>   bound to be the final nail in BTs coffin.

A few critics have predicted that if Bt-crops were released commercially,
resistance to Bt would develop so rapidly that conventional Bt products
would be virtually useless within a few years. This year is the third year
Bt-crops have been widely available on the market, so I suppose if the
critics are right, we might see some preliminary evidence of resistance
developing this year. Of course, such predictions are not based on any
model, rather they are based on mere speculation.

>   Key to preventing
>   resistance is the application of essentially 100% lethal
>   doses of the toxin, preferably at one, and only one,
>   vulnerable point in the insects lifecycle. In short,
>   use enough to nuke 'em all.

This is only one of the first strategies to be employed, but there are
several other strategies currently being applied as well. Resistance
management strategies are product-specific. For specific recommendations,
contact the manufacturer or the EPA. If you just want a brief review,
although somewhat dated, you might read the following article at:

>   BT-producing transgenic crops present a problem. While they
>   produce BT toxin all of the time, any one insect (esp
>   flying insects) may ingest only a sub-lethal amount of
>   the plant before moving on to non-BT foodstocks.

The same would also be true when Bt is applied as a conventional spray or
dust. An insect may ingest a sub-lethal dose and fly away in either situation.

>   It is
>   in this grey area ... between non-poisoned and lethally-
>   poisoned ... where individual resistance can become
>   amplified. Many insects will fall into the semi-resistant
>   bracket and survive to reproduce.

Apparently you are missing something here, because the conclusion above
certainly doesn't fit with your preceding hypothetical. Surviving a dose of
toxin because they are resistant is not the same as the surviving merely
because they avoided contact with the toxin. The population (and thus
individuals) must be exposed to the toxin before any selective pressure can
be exerted. The portion of the population that avoids exposure should have a
random distribution of alleles, including susceptible alleles, so avoidance
of the toxin clearly cannot amplify resistance alleles. This is basically
the theory behind the 'refugia' strategy.

>   If BT is placing pressure
>   on both larval and adult stages, the selective effect is
>   increased even more.

Essentially all of the currently available Bt products are designed to
manage the immature forms of insect pests. Bt pesticides do not place
selective pressure on the adult population for two reasons: the adults have
a different food source, and therefore do not ingest the toxin (e.g. moths
do not eat plant leaves), and the adult insects are simply not susceptible
to Bt toxins anyway (Cry3 toxins are a minor exception). So actually, the
selective pressure occurs at the larval stage.

>   So, BT should be used only for certain insect pests - a
>   subset of those it can actually kill.

Like any pesticide, it should be used in accordance with the label.

>   It should be used
>   in sufficient concentration to kill almost every single
>   target insect which even briefly enters the treatment
>   zone. Alas, these simple rules have not always been
>   followed.

What rules? Different products may have vastly different recommended
resistance management strategies. READ THE LABEL and follow the directions!

>   Being a "natural",
>   short-acting, insecticide with a rather narrow range of
>   organisms it will effect, the powers that be have cut
>   BT users slack.

The federal regulations are not 'slack' because the product is natural or
short-acting. Many natural and/or short-acting pesticides are toxic, and the
regulations regarding their use are quite strict. However, Bt is not
strictly regulated because it is essentially non-toxic to non-target
species, particularly higher animals. Whether a pesticide is 'natural' has
nothing to do with tolerances or action levels, which are based on safety.

>   only animals with alkaline gut chemistry are
>   affected and they are few - and, I think, all insects).

Not all insects - the various Bt toxins are generally quite specific for
well-defined groups of closely related target species. There are a few
toxins that are active against several genera of lepidopterans, but that is
about as non-specific as Bt gets. Most of the products have very narrowly
defined applications.

>   In short, "environmentalists" ENCOURAGE farmers to use
>   BT because it is extremely safe and "nature friendly".

Is that somehow a bad reason?

>   Farmers can realize increased profits because they are
>   free of many expensive regulations if they use BT.

Another bad reason?

>   "Nature friendly" as it may be, inappropriate application
>   of BT does have one serious side effect - on the useful
>   lifetime of BT itself.

Well there have only been two isolated cases of field resistance reported in
the last 40 years, so you are really only speculating here. Based on the
available evidence, predictions for the short useful lifetime you suggest
for these products seems unlikely.

>   It's a case of where using the
>   product destroys the product, not nature.

Using the product for the last 40 years has not destroyed it. Bt has been
used much longer than many synthetic insecticides, such as pyrethroids, to
which insects have already evolved significant resistance.

>   BT is something
>   which could have been reserved for special, sensitive,
>   situations - such as rivers, marshes or floodplains seriously
>   burdened with conventional insecticides.

Bt can be used for these situations now. Why not use it?

>   BT could have
>   offered relief. By using it willy-nilly though, it soon
>   will be useful to no one, including its manufacturers.

The manufacturers are currently investing billions of dollars developing Bt
products, with the expectation that these products will yield a significant
return on those investments. Do you know something that they don't?

>   Alas, money talks louder than common sense.

Or perhaps it's just that science is louder than rhetoric?  :-)

From: (Tracy Aquilla)
Newsgroups: sci.agriculture
Subject: Re: Ge engineered crops vs pesticides
Date: Sat, 6 Feb 99 16:50:31 GMT

In Article <36bb9034.0@motss>, (bill robertson)
>Tracy Aquilla ( wrote:
>[re: GE plants should be regulated as pesticides]
>: Good points, regarding plants engineered to express pesticides. Currently
>: the regulatory agencies evaluate GE plants on a case-by-case basis, however
>: EPA has already published a proposed rule to regulate plants engineered with
>: pesticide genes as pesticides per se, just as you suggest.
>In an article in the New York Times Magazine I read (sorry, I can't remember
>the date) about Monsanto's New Leaf Russet Potato (w/ BT gene), it was said
>that the USDA viewed it as a pesticide, making it the EPA's job to test it
>to see if it was safe. The EPA said that BT was already approved for use on
>potatoes so BT-producing potatoes should pose no great threat.

Note that EPA has since changed its position, and now considers plants
engineered with pesticide genes to be pesticides, because a Bt-plant is not
very different from a powdered Bt pesticide formulation - both are basically
Bt pesticides.

>They left it
>up to Monsanto to decide whether or not the New Leaf Russet should be
>considered Generally Recognized as Safe.
>Suprise, Monsanto said it was, so
>the EPA didn't run any of their own tests on it, trusting Monsanto's

No, GRAS is a term of art, meaning the agency accepts the widely held
opinion of the experts in the field that a compound is generally safe. The
GRAS list is an official list made by the regulatory agencies, and GRAS
status is never left for applicants to bestow upon their own products

>Monsanto has been quoted as saying that it is up to the government
>to test for safety, that Monsanto's only concern was making a profit. So the
>end result? New Leaf Russet spuds are being eaten by millions of Americans
>and no one has bothered to do serious toxicological studies of them.

You are assuming that the Bt toxin is expressed in the tubers. Is that true?
I know it is expressed in photosynthetic tissues, but I am not sure whether
it is expressed in the tubers. Even so, the toxin is a protein which is
easily digested, so there is no reason to assume any risk, particularly
since the toxin is inactive in mammals anyway. See below re toxicological

>BT, by the way, which is one of the most benign insecticides, is still
>required by law to carry a lengthy warning label on it, because it is a

Probably because the carriers and other inerts can be eye or skin irritants.

>The New Leaf Russets are apparently for this purpose considered
>by the EPA to be food,

No, FDA considers it to be a food, but EPA considers it a pesticide.

>so they are not required to carry any warning labels.


>The USDA says it's a pesticide, and wants nothing to do with it,

USDA really has no say, because the FDA and EPA trump its jurisdiction.

>the EPA says
>it's food and wants nothing to do with it.

No, the EPA has recently decided to regulate it as a pesticide, and will
require full toxicological testing. To date however, these products have
been evaluated on a case-by-case basis, which is a heavy burden on the agency.

>Monsanto says it just wants to
>make a quick buck. Why am I not reassured? Some french fries, anyone?
>The question is whether GE plants-cum-pesticides should be labelled as such
>in the store

If they present any significant risk, they should not be in the store in the
first place.

>with the same warning labels that the straight pesticide must
>have on it (I vote yes, but then I would love to see food labelled with the
>names and warnings from every pesticide used on them).

One should be aware that the Bt delta-endotoxins are nothing like other
pesticides, such as DDT, OPs, carbamates, etc., and are essentially
non-toxic per se. The safety of these toxins is due to their mode of action,
which is highly specific. The Bt toxins used in pesticides have been
carefully evaluated for mammalian and invertebrate toxicity in numerous labs
around the world for several decades, and are well known to be harmless to
higher animals. The volume of scientific literature is truly impressive
(i.e. thousands of papers and hundreds of books). The WHO uses Bt to manage
vectors of tropical disease, and many organic farmers use Bt on their crops.
Bt toxins have been used globally to manage insect pests for more than forty
years, and their safety has been well-proven.

However, there is clearly some logic in requiring minimal toxicity testing
whenever plants are bred to express increased levels of any natural toxin
that deters insect feeding.

From: Tracy Aquilla <>
Newsgroups: sci.agriculture
Subject: Re: Natural Toxins
Date: Tue, 07 Sep 1999 17:00:30 -0400

Torsten Brinch wrote:

> >But then there is this opinion:
> >
> 99
> It is not clear to me which scientific basis Alan Gray has for his opinion?
> that consumers of organic food has a 30 times increased risk of being
> 'poisoned' or experiencing 'septic chock' from ingesting produce
> which has been treated with B.thuringiensis (Bt). Afaik, Bt products are
> freely available pesticide products, that is they are not special
> to organic food production, and they can be sold without restrictions
> to anybody.

Perhaps the author is taking note of the fact that some rather potent
enterotoxins have been isolated from certain commercial preparations of Bt?
Because Bt is very closely related to B. cereus, I hypothesized this might be
the case more than a decade ago. Subsequently, the literature has confirmed my
hypothesis. I have cited the references here several times. This is a potential
public health problem that deserves some attention, but I don't expect it will
get any.

> [snip]
> "The delta-endotoxin proteins of B. thuringinesis have been
> intensively studied, and no indications of mammalian toxicity have been
> reported. Furthermore, approximately 176 different B. thuringiensis
> products have been registered since 1961, and the Agency has not
> received any reports of dietary toxicity attributable to their use.
> This is especially significant because FIFRA section 6(a)(2) requires
> registrants to report any adverse effects to EPA. Therefore, EPA does
> not expect any mammalian toxicity from this protein in plants based on
> the use history of B. thuringiensis products."

The delta-endotoxin proteins are not the problem. It is the enterotoxins that
are a potential problem. The enterotoxins are found in 'conventional' Bt
preparations, not the GMO plants.

From: Tracy Aquilla <>
Newsgroups: sci.agriculture
Subject: Re: Natural Toxins
Date: Wed, 08 Sep 1999 17:05:59 -0400

Harold Lindaberry wrote:

> Torsten Brinch wrote:
> > Harold Lindaberry skrev i meddelelsen ...
> >
> > >Torsten Brinch wrote:

> [snip]
> > >It would be nice to see some long term toxicology data and other
> > >adequate data - One ( I ) would not expect a synthetic pesticide to be
> > >approved without adequate testing and IMO I see no reason that
> > >because it is " All natural " is should be approved either.
> >
> > But that is not the reason EPA gives for approving those genetically
> > engineered bt plants. They base it on relatively short term feeding
> > experiments with similar toxins from bacteria, and the premise,
> > that protein toxicity is always acute. The premise, 'all natural'
> > does not enter anywhere in the approval.

One might also keep in mind that humans have been eating Bt delta-endotoxins for a
long time with apparently no toxic effect.

>     Perhaps the term should have been ubiquitous rather than all natural.-
> while it does not appear in the actual language of the legislation IMO it is in
> the spirit of it.

The approval of the products is based on the empirical evidence that Bt
delta-endotoxins are non-toxic to mammals, based on decades worth of testing and
analysis. One can find such evidence in the journals if one cares to look for it.

> > >I won't even
> > >bother to point out the potential hazard examples. I was interested to
> > >see Aspergillus flavus added to the GM gene gun arsenal - an

You made this assertion at least once before and it is absolutely false. There has
been no approval of A. flavus for use in genetically engineering of plants, whether
using the so-called gene gun or any other means.

> [snip]
> > >Perhaps he would just like to see some substantiating data that bt is "
> > >safe for the intended purpose "

Bt endotoxins are indeed safe for their intended purpose. The data are
overwhelming, and there are no data to support a contrary view. Also, one should
take care to distinguish between Bt itself and plants engineered to express Bt
genes, as they are not exactly the same thing. While the GMO plants are only about
15 years old, Bt has been around for a long time.

> [snip]
> > >> "The delta-endotoxin proteins of B. thuringinesis have been
> > >> intensively studied,
> >
> > >    ??????

I have offered many times to send you a reference list. One afternoon in the
library could cure your affliction.

> > It is your EPA who writes this stuff, not I, Harold. And
> > that's what they say.

And besides, it's true!

> Afaik, the interest in genetical
> > engineering indeed should imply intense studying
> > of these toxins. So the EPA statement seems
> > quite plausible to me.
>     My EPA ?????

Of course, Torsten meant your EPA as in the _US_ EPA.

> > >> and no indications of mammalian toxicity have been
> > >> reported.

Correct. However, there are many reports that the Bt delta-endotoxins are not toxic
to mammals.

> [snip]
> > >> Furthermore, approximately 176 different B. thuringiensis
> > >> products have been registered since 1961, and the Agency has not
> > >> received any reports of dietary toxicity attributable to their use.
> >
> > >Since bt has generally been highly touted by the health food faddists
> > >would one expect it.?

Never heard that one before. Is Bt supposed to be a probiotic or what?

> > Maybe it is just that it is the case, that it has not been possible
> > for anyone to attribute any actual dietary toxicity to these products.
>     Again analytical method ?????

The endotoxins have been studied extensively. All one can logically conclude is
that there is simply no dietary toxicity to these products that has ever been
detected. This is the same approach used in evaluating any other product.

> > >besides the residue patterns of sprays and GM
> > >crops are not the same and with sprays the grower always has the
> > >option of not spraying which is usually ) with GM you plant it you got it.
> >
> > Yes, that is true.

True of the first generation products produced using the crudest technology. Watch
for selective expression coming to a GMO plant soon. They are already in the works,
they just take several years to make it from the lab to the front page of the

> > Same as with pesticides, I suppose? In the end you just have
> > to release those genetically engineered plants anyway
> > and see what happens, to those who eat them, just like with
> > pesticides. If problems should crop up, you must eventually
> > just stop using the products.
>     Just how does one know whether the soybeans or corn is GE once it gets in
> to the system ? I hate to answer a ? with a ?

Here's another question for you:  just how does one know whether the soybeans or
the corn has been treated with OP pesticides (for example)?

> > >Why do they always add the prefix endo ( as an out when it  hits
> > >the fan ) ?

Simply because that is what they are by definition, and further to distinguish them
from the other toxins that are found in Bt, such as cytotoxins and exotoxins. The
endotoxins are generally endosomal in nature and are formed as parasporal crystals.

> > This last bit was written by me, so the blame is on me for this
> > lapse of precision in language use. In relation to bacteria it makes
> > sense to distinguish between endo- and exo-toxins. I should
> > of course have written that these approved genetically
> > engineered plants contains 'huge amounts of toxins similar to
> > Bt endotoxin'
>     The question might also be are there other toxins produced ?

Yes. I must have mentioned this dozens of times over the last few years.

From: Tracy Aquilla <>
Newsgroups: sci.agriculture
Subject: Re: Natural Toxins
Date: Wed, 08 Sep 1999 17:38:58 -0400

Harold Lindaberry wrote:

> Tracy Aquilla wrote:
> > Torsten Brinch wrote:
> >
> > > Harold Lindaberry skrev i meddelelsen ...
> > > [snip]
> > > >I won't even
> > > >bother to point out the potential hazard examples. I was interested to
> > > >see Aspergillus flavus added to the GM gene gun arsenal - an
> > > >interesting new choice bullets. From the early data I saw it's a
> > > >lot better insecticide than bt.
> > >
> > > Noone has suggested that crops should be engineered to
> > > produce aflatoxin. As it is a secondary metabolite, not
> > > a protein, genetically engineering this trait into a plant
> > > would  be tricky at the current rudimentary level of technology.
> > > The safety aspects of doing it, if it came to it,  would indeed
> > > be daunting.
> > >
> > > >> If he hasn't such new information then he is just
> > > >> airing an unsubstantiated opinion, obviously in an attempt to bash
> > > >> organic food production. I don't mind if Alan Gray for some reason
> > > >> carries an  irrational grudge against organic food production, but he
> > > >> must be able to distinguish  between unsubstantiated opinion and
> > > >> scientific knowledge --otherwise, IMO, he does not qualify as a
> > > >> scientific adviser to the government.
> > >
> > > >Perhaps he would just like to see some substantiating data that bt is "
> > > >safe for the intended purpose "
> >
> > Do you mean Bt itself, or plants engineered to express Bt toxins? There are
> > volumes of information demonstrating that Bt is safe for its intended purpose.
>     Both - in data submitted to the OPP and published

Well apparently the EPA has seen the data, even if you have not.

> > > >> "The delta-endotoxin proteins of B. thuringinesis have been
> > > >> intensively studied,
> > >
> > > >    ??????
> > >
> > > It is your EPA who writes this stuff, not I, Harold. And
> > > that's what they say.
> >
> > Indeed, and it is absolutely true.
> >
> > > Afaik, the interest in genetical
> > > engineering indeed should imply intense studying
> > > of these toxins. So the EPA statement seems
> > > quite plausible to me.
> > >
> > > >> and no indications of mammalian toxicity have been
> > > >> reported.
> >
> > True, there are many reports, but not a single one has identified any mammalian
> > toxicity of Bt delta-endotoxins.
>     Long term chronic studies ?

I cannot cite any from memory, but that does not mean there aren't any. Also note
that the human population consumes Bt regularly and it has been a part of the diet at
elevated levels for at least 30 years. I would say that qualifies as pretty long
term. Based on this fact, Bt delta-endotoxins are almost certainly GRAS, and I doubt
you could find a single qualified expert that would state otherwise.

> > > >I thought the job of regulatory agencies was to evaluate data
> > > >demonstrating safety of pesticides?
> > >
> > > Well, they can't evaluate data which have not been
> > > reported to them, can they.
> >
> > Note also that pesticides and pesticide-engineered plants are not treated
> > equally by EPA, although this is changing.
>     Why ? Isn't that a violation regulations ?

No, changing the regulations is not a violation of the regulations. In fact, the
government routinely grants itself exemptions from certain of its regulations. In
this case, however, the regulations are being changed to make them more strict in
regard to the Bt-crops, not less.

I wonder if we will ever find anything else to talk about!

Actually, I just thought of something. How would you like to start a new thread on
dealing with deer eating your garden? I recently moved to the finger lakes region of
central NY state. I planted a garden rather late this summer, not expecting much. I
have had vegetable gardens in deer infested areas before, but have never seen the
likes of this summer. The deer have mowed the corn, the greens, the cucurbits, the
beans, and even the tomato and pepper plants. I seem to remember you have had similar
problems. What have you done to deter them, other than planting a lot of extra stuff
or getting after them with your gun? I will be doing some bow hunting soon, but in
the meantime I am covering my crops with fiber row covers. So far, it seems to be
working. Any other ideas that might be more manageable on a larger scale?

From: Tracy Aquilla <>
Newsgroups: sci.agriculture
Subject: Re: Genetically Engineered Foods Debate
Date: Fri, 19 Nov 1999 12:37:09 -0500

Harold Lindaberry wrote:
>     This is incorrect bt - is only effective some Lepidoptera and marginal in
> some cases..

Harold should know better than this by now - I can't count the number of
times I have told him over the last several years that Bt is effective
against a wide range of species, including Diptera, Coleoptera,
nematodes and even fungi. Bt is a broad class of pesticides, producing
hundreds of different toxins having variable activities against numerous
different pests.

From: Tracy Aquilla <>
Newsgroups: sci.agriculture
Subject: Re: Genetically Engineered Foods Debate
Date: Fri, 19 Nov 1999 12:37:35 -0500

Harold Lindaberry wrote:
> Marty Sachs wrote:
> > Bt-corn does not excrete the 'dammed stuff'.  The 'dammed stuff' stays in
> > the plant's cells (unless an insect pest begins eating plant tissue and
> > therefore ingests the BT).
>     Don't forget the animals and humans that eat the corn - also when the plant
> residue is recycled ( decomposes ) it is released.

No, the decomposed protein has no insecticidal activity.

> > About the closest example I've seen raised to
> > corn plants excreting the 'dammed stuff', is during pollination (pollen
> > grains contain a small amount of BT).  However, this is a very short
> > period in the life of the corn plant, and as hybrid corn is so uniform,
> > the vast majority of plants in a field begin and finish shedding pollen in
> > less than a week.
>     It is a protein source for bees and some other insects.

The delta endotoxins expressed in the plants currently in use are
harmless to bees. N fact, Bt formulations have been used in beehives to
manage wax moths for many years.

> > By any stretch of the imagination there is far less exposure (collateral
> > damage) of insects (or anything else) not directly eating BT-corn, then
> > there is in an organic farm field that is sprayed only once with BT.  As I
> > understand it, because BT washes away so easily, many organic farmers
> > spray more than once during the growing season.
>     Actually the fact that spraying is normally only required on 10 to 15% of a
> crop vs. bt contamination takes place from planting right up to ( and after )
> harvest on bt GM crops it is difficult for me to see how less potential hazard is
> involved

The toxin concentration per acre in the sprays is several fold higher
than that in the GMO plants. Note also that second generation Bt-crops
will soon be available that can selectively express the toxin.

> - specially when one considers the lack of animal test data

We have been through this many times - there are reams of data regarding
the non-toxicity of delta endotoxins to animals. Spend an afternoon in
the library and you will find dozens of published papers dating back for

From: Tracy Aquilla <>
Subject: Re: GM Foods (link)
Date: Fri, 03 Dec 1999 13:07:32 -0500

Charles Rader wrote:
> If you are only aware of the original story that Bt corn kills Monarch
> butterflies, you might wonder if your sources of information are
> honestly informing you, or playing with your mind.

Anyone with the slightest experience with Bt or knowledge of the Bt
literature would not be surprised at the result of the Cornell paper. Of
course, if you feed them enough of the type 1 delta endotoxins of Bt,
most species
of caterpillars are going to die.

> The other major point you raise is that the toxin harms honeybees. But
> it doesn't. It has been in use for 100 years in its natural form and it
> is very well established that it harms ONLY insects of the order
> lepidopetera -- butterflies and moths. It's been tested on all kinds of
> other insects, mammals, fish, etc.

That actually depends on the specific Bt toxin, and there are hundreds
of them. Some kill dipteran pests (e.g., mosquitoes and blackflies),
some kill coleopteran pests (e.g., Colorado potato beetles and others),
and some kill both diptera and lepidoptera.

There are also some Bt strains that produce exotoxins that can kill
mammals, and some strains that produce cytolytic toxins that can lyse
red blood cells. Some of the more recently discovered Bt toxins kill
fungi and others nematodes.

Of course, the toxins that were cloned into the Bt-crops are
lepidopteran-specific, although I believe there is at least one corn
variety on the market that carries both type 1 and 3 toxins.

Newsgroups: sci.agriculture
From: (Tracy Aquilla)
Subject: Re: Toxin released from Gene-Modified Corn
Date: Sun, 5 Dec 99 16:38:21 GMT

In Article <>, David Rogers
<> wrote:

>It seems the existing scientific system must be working as US scientists
>have uncovered a specific problem with genetically modified corn. Dr
>Guenther Stotzky and researchers at New York University have shown that
>BT corn -- the seed variety which is resistant to corn borer pests --
>releases an insecticide through its
>roots into the soil.

How could this be a problem? The toxin has a narrow spectrum of activity -
limited to lepidopteran larvae. Which species of soil dwelling lepidopteran
larvae should we be concerned about? Note also, Bt is a naturally occurring
soil dwelling bacterium - this is where the toxin came from in the first
place, and this is where the Bt eventually ends up when it is applied in Bt
sprays. In fact, Bt sprays have conventionally been applied at a rate of up
to 100 grams of toxin per acre, whereas the Bt toxin in corn is expressed in
vivo at a rate of about 5 grams per acre. Even if all of the toxin produced
in the GMO crops were exuded from the roots (which, of course, it isn't),
the impact would be far less than that of a single spraying.

From: Marty Sachs <>
Newsgroups: sci.agriculture
Subject: Re: Toxin released from Gene-Modified Corn
Date: Sun, 05 Dec 1999 16:30:38 -0600


Bacillus thuringiensis is a natural inhabitant of soil and constantly
releases its toxin into soil.  If a larval insect that is susceptible to
its toxin, eats something that has spores on it, the larval insect will
die.  Similarly if people eat something containing Clostridium
botulinum, they could die.  Tetanus is caused by Clostridium tetani, a
spore-forming organism similar to C. botulinum.

Bacillus anthracis, causes anthrax in humans and domestic animals.
However, medically useful antibiotics are produced by B. subtilis
(bacitracin) and B. polymyxa (polymyxin B).

Clostridium and Bacillus are closely related bacterial genera.  Both
produce endospores.  In some species, these endospores contain proteins
that are toxic to a narrow range of organisms.  These bacteria and the
toxins that they produce, have been widely studied for over 100 years.

In terms of releasing bacteria containing genes from Bacillus
thuringiensis, this is done quite frequently on organic farms.  B.
thuringiensis causes disease in insects (different subspecies affect
different insect orders); B. thuringiensis insecticides are harmless to
vertebrates but effective against pests of agricultural products.
Growing crop plants that have a BT toxin gene certainly posses no
greater threat to the environment (or to people) than the natural
bacteria already inhabiting the soils of the field, or the organic farm
that has been sprayed with BT toxin.

   Best regards,

      -Marty Sachs

In article <>, David Rogers
<> wrote:

>The release of transgenic plants and bacteria containing genes from
>subspecies of Bacillus thuringiensis (Bt) that code for insecticidal
>proteins may pose a potential hazard to the environment. The continual
>production of the toxins, especially those encoded by truncated genes
>that express active toxins rather than inactive protoxins, by growing
>transgenic organisms that are indigenous or adapted to the specific
>habitat may exceed consumption by insect larvae and biotic and abiotic
>inactivation. Hence, the toxins could accumulate to concentrations that
>may constitute a hazard to nontarget organisms and that could result in
>the selection and enrichment of toxin-resistant target insects. The
>accumulation and persistence would be enhanced if the toxins are bound
>on particles (e.g., clays and humic substances) in the environment and,
>thereby, are rendered less accessible for microbial degradation.
>Gene modification may have impacts unrelated to their immediate
>application. It may be best to research these implications before
>applying them on a massive scale and before negative impacts may harm

In article <>, David Rogers
<> wrote:

>It may be so. I am not sure how scientists can be so certain of the
>narrow spectrum of BT toxins in field conditions as it will be subject
>to innumerable microorganisms and variables. Perhaps it is wise to
>compare the insecticidal activity of free and particle-bound toxins, as
>well as their toxicity to microorganisms and evaluate the effects of BT
>toxins on microbial populations and processes in soil (e.g., metabolic
>activity, transformations of carbon and nitrogen, activity of "soil"
>enzymes, species diversity).

From: Tracy Aquilla <>
Newsgroups: sci.agriculture
Subject: Re: Toxin released from Gene-Modified Corn
Date: Mon, 06 Dec 1999 11:22:07 -0500

Harold Lindaberry wrote:
> Tracy Aquilla wrote:
> > [snip]
> > >> >If you want to get a broad spectrum of all of
> > >> >the above species in one shot go to Aspergillus falvus.
> > >>
> > >> Who wants a broad spectrum? The point of using Bt delta endotoxins is that
> > >> they are known to have a narrow spectrum of activity.
> > >
> > >    There are damned few crops with one type of insect pests.
> >
> > So, there are also damned few crops that express Bt toxins. The purpose of
> > these crops is not broad spectrum protection. If growers didn't find their
> > narrow spectrum of pretection useful, they probably wouldn't buy them.
>     time will tell

Indeed. However, over the last four years, they have been selling like
hotcakes. Perhaps Torsten will give you a few of his 10,000 or so
years.  ;-)

> > >    Evidence ? You cling to yours I'll cling to mine.
> >
> > OK. I am uite interested in any evidence you can present that indicates CRY1
> > toxins are toxic to humans. The abundant evidence to date indicates that
> > they are not
>     Then why are the data references not published in the exemptions announcements?

How would I know - ask EPA (sorry, I don't work there).

>     There's no doubt about it being a different compound for sure - attitudes do
> change IMO sometimes not for the best just because something is produced in nature
> doesn't mean it is safe .

Well of course, that should be obvious to most people (although,
unfortunately, it isn't). However, the regulatory scheme in regard to Bt
toxins is not based on the (erroneous) premise that 'if something is
produced in nature, it is safe', rather, it is based on overwhelming
evidence of non-toxicity to mammals.

To appease Harold, I did a quick web search for some easy-to-find data.
The information below came from a single web page out of more than 40
hits. See:


The text below is excerpted from the page cited above.

"B.t. a bacterial insecticide, has no known toxic or pathogenic effect
in humans or other mammals.  The Agency, has reviewed and evaluated all
available data, including those data submitted to the Agency in support
of the registration of B.t. products, as well as data from published
literature, concerning B.t. varieties kurstaki, aizawai and israelensis.
All three of these varieties of B.t. are covered by this fact sheet.

Adequate data were available to assess the acute oral, inhalation,
dermal, toxicological, and other biological effects of this bacterial
agent.  The Agency's review of these data determined that no data gaps
exist in the toxicology data base and no major environmental mammalian
safety concerns (except for certain endangered species of Lepidoptera)
were identified......

The delta-endotoxin has been shown to be harmless to mammals and is
released only under a highly alkaline environment, such as that in the
midgut of lepidopteran larvae. In addition to delta-endotoxin, some
strains of B. t. produce another toxin called beta-exotoxin (also known
as thuringiensin) which is secreted externally to the cell wall, and
which has a broad range of toxicity to insects. Currently registered
B.t. products comply with 40 CFR 180.1011 which requires that any B.t.
product exempt from the requirements of a tolerance must contain no
amounts of beta-exotoxin, as determined by the fly larvae bioassay. The
Agency has determined that bacterial cell-free B.t. beta-exotoxin is a
chemical pesticide, and will be treated as such. There are no products
registered with beta-exotoxin. Such products will require separate
toxicity testing prior to consideration for registration. If any B.t.
products with beta-exotoxin are registered, they will be dealt with
under a separate standard when appropriate......

B.t. was one of the first insect pathogens registered in the United
States and as such was required to undergo an extremely rigorous
mammalian toxicity/infectivity evaluation. Much of the testing program
for B.t. was based on the testing requirements for conventional chemical
pesticides, and the data base required for the original registration of
B.t. was more extensive than that currently required by 40 CFR Part 158
(c). Accordingly, no mammalian toxicity/infectivity data gaps exist for
B.t. Many acute toxicity/pathogenicity studies with various varieties of
B.t. have been conducted using several routes of administration in rats,
rabbits, and guinea pigs. Among the various studies reviewed, the
highest dose tested was 6.7 x 10(11) spores per animal. There were no
significant adverse effects associated with these studies......

2. Residue Data

     No data are required in this area, because no residue of concern have
been designated. Additionally, an exemption from the requirement of a
tolerance for all raw and processed agricultural commodities has been
established.  The exemption is partially based on the condition that beta-
extoxin is not present in B.t. formulations.

3. Toxicology Data

     Since B.t. was one of the first insect pathogens to be registered in
the United States, it was required to undergo an extremely rigorous
mammalian toxicity-infectivity evaluation program. The regimen was more
stringent than that currently required by 40 CFR Part 158 Section (c). Much
of the testing program was based on the testing requirements for generating
conventional chemical pesticide data. Consequently there are no mammalian
toxicity/infectivity data gaps for B.t. A wide variety of mammalian
toxicity/pathogenicity studies have been conducted with B.t. kurstaki,
israelensis, and aizawai using several routes of administration in rats,
rabbits, and guinea pigs. Among the studies reviewed the highest dose
tested was 6.7 x 10(11) spores per animal.These data indicate that there
are marginal, if any deleterious effects cause by the use of products
containing B.t. Most of the data is on B.t. varieties kurstaki and

     The following toxicology studies are examples of the types of
toxicology data that were submitted in support of the current B.t.

Bacillus thurinqiensis Toxicity/Infectivity Profile(1)

Variety            Tested       Route              Effect

Kurstaki           rabbit       oral           No acute oral
                                               LD50 > or = to 2.0 x

Kurstaki           rat          oral           No acute oral
                                               LD50 > or = to 2.67

Israelensis        rat          innoculation   No acute oral
                                               LD50 > or = to 6.9 x

Israelensis        rat          oral           No acute oral
                                               LD50 > or = to 1.2 x

Kurstaki           rat          oral           No acute oral
                                               LD50 > or = to 4.7 x

Kurstaki           rat          innoculation   No acute oral
                                               LD50 > or = to 3.4 x

Israelensis        rabbit       innoculation   No acute oral
                                               LD50 > or = to 6.28

Kurstaki           rat          innoculation   No acute oral
                                               LD50 > or = to 4.6 x

Kurstaki           rat          inhalation     No acute oral
                                               8 x 10(11) spores/animal

Kurstaki           rabbit       innoculation   No intraperitoneal infec-
                                               tivity; LD50 > or = to
                                               6.9 x 10(7)

Kurstaki           rabbit       innoculation   No corneal opacity,
                                               tival redness reversible
                                               with 7 days dose: 6.9 x
                                               10(7) spores/animal

(1) Based on data as reported. No attempt was made to convert units or
iterpret end points.

Bacillus thurinqiensis Toxicity/Infectivity Profile(1)

Variety            Tested       Route               Effect

Kurstaki           human        oral           No toxicity/infectivity;
                                               dose:  1 gm/day for three
                                               consecutive days

Kurstaki           guinea piq   innoculation   No sensitizations;
                                               index = 0.2 to 0.3

Kurstaki           rat          innoculation   No toxic or virulent
                                               effects; LD50 > 5 gm/kg

Israelensis        rat          Intracerebral  A dose of 10(7) organisms
                                (ic)           killed the test animals;
                                innoculation   death was probably due to
                                               the massive i.c. inoculum
                                               and not any infective
                                               process; most of the
                                               died within 24 hours.

(1) Based on data as reported. No attempt was made to convert units or
interpret end points."

If one were to perform a complete literature search for data relating to
mammalian toxicity of the various B.t. toxins, one would have to spend
months reading all of the published literature in order to come up to
speed with what is known about it. Reviewing all of the EPA documents
would probably take again as long. The volume of data is truly immense
and dates back several decades.
But I expect Harold will stick to his guns anyway!

From: Tracy Aquilla <>
Newsgroups: sci.agriculture
Subject: Re: Toxin released from Gene-Modified Corn
Date: Tue, 07 Dec 1999 10:32:31 -0500

Harold Lindaberry wrote:
> Tracy Aquilla wrote:
> > Harold Lindaberry wrote:
> > > > it is a toxicant produced by a bacteria or inserted into a GMO
> > > > plant nothing more nothing less
> >
> > Of course it is more - Bt is actually a bacterium and is routinely
> > applied as such in the field. It is not merely a toxin, as you claim.
> > How can you assert that its potential infectivity is irrelevant,
> > particularly when you seem so concerned about its toxicity?
>     If you think it's not the crystals doing the job I think you need to
> reevaluate.

The crystals are not the only thing "doing the job" and in any case, are
not the only thing being applied to the plants. Note that the spores
also contain endotoxins, and the fact that spores are applied to food
crops presents a potential public health issue. Thus, EPA was prudent to
assess the effects of the entire organism, instead of only worrying about
the isolated endotoxins.

> > >- the fact that in their reported test animals died in the one
> > >reported - they seem to brush it off as we must have fed them to much
> > >seems to me to be an off the wall comment.
> >
> > Well, you might want to re-read the report. "A dose of 10(7) organisms
> > killed the test animals; death was probably due to the _massive i.c.
> > inoculum_ and not any infective process; most of the animals died within
> > 24 hours."
>     As I said the infection process has little to do with insect toxicity.

There is no infection process in the insects, so of course, it has
nothing to do with toxicity. See above re public health and applying
microorganisms to food plants.

> > BTW, where are the data that indicate CRY1 toxins are toxic to mammals?
>     Or are not for that matter

Well, you may not think it is enough, but I supplied extensive data from
EPA indicating there is no known mammalian toxicity. You have not
provided any evidence whatsoever to support your position that there is.

> [snip]
> > I am not saying anything - the quote above is from the EPA, not me. The
> > EPA apparently saw fit not only to test for toxicity, but infectivity as
> > well, just to be on the safe side, since Bt is a bacterium and not just
> > a chemical pesticide.
>     that kills mostly by the process of the crystal activity.

Wrong. See above re spore activity. Spores are not the same thing as
the parasporal crystals.

> > (However, as an insect pathologist, I can tell you that Bt is not a true
> > pathogen of insects, and the pesticide formulations do not kill by
> > infecting the insects.)
>   As I recall the last time you mentioned your training it was as a genetic
> expert.

I rather doubt I have ever claimed to be an expert, as I tend to be
suspicious of anyone who does. I do have a PhD in molecular genetics
though, in addition to a MS in insect pathology from UC Riverside. My
masters thesis and doctoral dissertation work were done in the same lab
in entomology and focused mainly on the host specificity of
microorganisms used to manage insect pests. I am not an expert, but I do
know a little about it.

From: Tracy Aquilla <>
Newsgroups: sci.agriculture
Subject: Re: Toxin released from Gene-Modified Corn
Date: Tue, 07 Dec 1999 13:49:26 -0500

Harold Lindaberry wrote:
> Tracy Aquilla wrote:
> > >
> > > >The experimental work indicates that there is no acute toxicity and the
> > > >endotoxin is rapidly digested to yield dietary nutrients.
>     Suggest you go to
> to see how
> much data was submitted - I see a a 4 hour invitro lab gastric juice test

Actually, if you read more carefully, you will see that in this
particular case, it was a test for in vitro digestibility under
simulated gastric conditions using simulated gastric juice. Many
proteins, including Bt endotoxins, which are generally stable in an acid
solution, will not degrade in 4 hours under such conditions. Proteases
are necessary to degrade the endotoxins.

The petition also states:
"The extensive mammalian toxicity studies performed to support
the safety of Bacillus thuringiensis - containing pesticides clearly
demonstrate that the tested isolates are not toxic or pathogenic
(McClintock, et al., 1995, Pestic. Sci. 45:95-105)."

> showing 4 hour stability hardly supports this contention IMO. If you can find
> meaningful data in this submission I would like you to point it out. to me.

I agree the in vitro simulated gastric juice assay is probably not very
meaningful, as it would not indicate how rapidly the protein would be
digested in vivo.

However, the point of the petition is to obtain an exemption for
disclosing a method of detecting and measuring residue of the pesticide.
These are plants that are intentionally designed to produce the
pesticide, so of course it is assumed that the pesticide will be present
in the food in the same concentration found in the plants. Further, it
is a simple matter to measure the level of the endotoxin protein in the

Keep trying, Harold, and please let me know when you actually find any
data that indicate that a Bt endotoxin has any activity in mammals.

From: Tracy Aquilla <>
Newsgroups: alt.agriculture.misc,alt.sustainable.agriculture,sci.agriculture,
Subject: Re: Biotech-corn hazard low, early tests show Field studies suggest
Date: Mon, 27 Nov 2000 10:31:49 -0500

Somebody wrote:

> >The `anti-gms' use the phenomenon to draw attention to that fact that
> >things were not well though out before release of the Bt crops.

If that is the case, then these 'anti-gms' choose a poor example to
illustrate their point.

It was well known, way before any Bt crops were even field tested, that the
Cry1A delta-endotoxins are toxic to the larvae of the Monarch butterfly.
Further, the potential for damage to non-target insects, including the
Monarch butterfly, was considered by the USDA in its assessment and
pre-market approval of Bt maize. Indeed, upon review of this specific issue,
the regulators determined that any potential impact on the Monarch butterfly
would be insignificant, partly because corn and corn pollen are not typically
a part of the larval diet for this insect. And since the release of the
bt-corn, the data have borne out USDA's prediction.

So, in fact, this case is a good example of the regulatory authorities
identifying a potential risk beforehand, which shows that things actually
_were_ "well though out before release of the Bt crops."

From: Tracy Aquilla <>
Newsgroups: sci.agriculture,sci.environment,sci.chem
Subject: Re: Scientists Count Weeds in Cornfields
Date: Fri, 01 Dec 2000 16:53:48 -0500

fungee wrote:

> In article <907vb0$svf$>,
>   Environmental News <> wrote:

So it appears Chive got himself another new ISP and pseudonym?

> > Laboratory research at Cornell University showed that the pollen was
> > toxic to monarchs,

Not particularly informative, since it was already well known decades ago
that Bt delta-endotoxins are toxic to the larvae of Danaus plexippus (aka
the monarch butterfly). Indeed, before approving Bt-crops, USDA and EPA were
well aware of the potential effect on this and other non-target lepidopteran
species (some considered endangered), but determined that the Bt crops were
unlikely to pose any significant risk to these non-target species, based on
the available knowledge regarding several major parameters that would affect
the magnitude of such risk (dietary habits of the larvae, timing of pollen
shed and eclosion, etc.).

> > but it is still unclear whether the pollen is dense
> > or toxic enough in cornfields when the butterfly larvae are feeding to
> > be a threat to them.

Based on the most recent data, it is becoming increasing clear that Bt crops
present no significant risk to the monarch butterfly. According to Dr.
Richard Hellmich, a research entomologist with USDA-ARS, there are currently
about 2000 studies being conducted on the effect of Bt crops on monarchs,
and based on the preliminary data, there appears to be little if any
negative effect on the monarch butterfly. See e.g., vol. 18 Nature
Biotechnology p. 701 (2000).

> > An Iowa State University study published this summer suggested it was.

Actually, that statement somewhat mischaracterizes the results of the Iowa
State experiments that were published in Oecologia, since they never really
measured pollen density in corn fields.

> > One in five monarch larvae died after being exposed to the toxic corn
> > pollen for two days, the study found, but even that research was
> > partially conducted under lab conditions.
> >
> > The Minnesota researchers, who have yet to publish their study, counted
> > butterfly larvae at five sites in the state this summer and found the
> > caterpillars were more common inside than outside cornfields.

> > ``What this research says is that if pollen falls in densities that are
> > high enough to harm monarchs that the monarchs are there,'' she said.
> I wonder what the conclusion would be if fewer Monarchs were found
> inside the corn fields than outside - The pollen is killing the
> Monarchs!  Therefore, the correct conclusion should be that the pollen
> is helping the Monarchs, right?  Maybe it's just me.

It really doesn't make much difference now. It is apparent that the monarch
population in the US is doing quite well, in spite of any potential risk
posed by Bt crops. More importantly, the two Bt transgenic corn events
(i.e., Bt176 and CB351) that produce pollen toxic to monarch larvae are
being dropped by the manufacturers, in favor of GE cultivars that either do
not express the toxin at high levels in pollen (e.g., Bt11 and MON810), or
that use newer delta-endotoxin genes that have very low toxicity to monarch
larvae (e.g., Cry9C) or are non-toxic to monarch larvae (e.g., Cry1F).

Index Home About Blog