Cease & Desist Bt Use?

[Paul Cherubini]

Doug Dawn wrote:

> So is the cause that Bt use should cease and desist or is it that it should
> not be delivered in GMO's?  How it is delivered seems to me to have no
> relationship whatsoever to the resistances that some worry could be a problem
> and need to be investigated further.

Good point, Doug

Another point to consider which has not been brought up yet is Bt's
inherent effectiveness (or lack thereof) against the TARGET leps, not
just the non-target ones, whether delivered to the insects in liquid
spray form (e.g. forest sprays for gypsy moths) or incorporated into
growing crops.

Who has ever heard of a TARGET pest being wiped out by Bt sprays on a
regional basis? Have gypsy moth infestations been wiped out anywhere on
the continent on account of Bt use or merely controlled temporarily?  Is
anyone expecting regional (Midwest corn belt) populations of the
european corn borer moth to suffer a dramatic decline as a result of the
widespread planting to Bt corn?

So far as I know the answer to the above questions are both no. Only
people with years and years of hands on experience with Bt  and other
insecticides can appreciate the true capabilities and limitations of any
of these products. All any of these products have ever been able to
accomplish is temporary reductions in target lep populations. We are
only talking about 30-70% kills against TARGET leps - the ones that get
drenched with the spray and somehow survive.

Like perhaps a few others on this list, many times I've worked with
organic growers and helped spray  liquid (DIPEL) Bt formulations every
week for several consecutive weeks on crops infested with moth lep
caterpillars. After the 4th week,  the larval population may have been
reduced 50-80%, but that is still alot of surviving caterpillars living
on the plants. Extermination is never achieved. Given this fustrating
and agonizing experience trying to kill lep worms with Bt WHEN WE
PURPOSELY WANT TO, those of us in the ag chem industry simply can't
relate to the fears of those without crop production experience who
think incidental spray drift (or in this case pollen drift) could
conceivably impact non-target leps in a substantial way. So that
background largely accounts for what comes accross as our "living in
denial" attitude about the potential impacts of Bt on an insect of
widespread abundance like the monarch butterfly. That is why we make the
challenge to others to come up with realistic heavy impact scenarios.

Here is an analogy: If a Cornell scientist put flouride or chlorine on a
milkweed leaf and monarch caterpillars died when they ate it, how many
of you on this list think it would be conceivable that chlorinated or
flourinated drinking (i.e.crop irrigation) water would pose a threat to
monarchs and other non-target leps? If most of you would say it's
inconceivable, how would you make your case to the public that the
studies the hypothetical Cornell scientists want done on flouride and
chlorine are a waste?  How would you answer critics who would say you
are immoral and valueless and just interested in being able to trade in
that Lexus every year for the newest model?

Paul Cherubini, Placerville, California