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Re: Spinosad



Thanks , Chuck , for the edifying discussion on spinosad. One remaining
point may be "how soon will  spinosad be incorporated into GM crops? The
answer seems to be not very soon. Spinosad is different from Bt cry
toxins which are  protein products of a single gene scavenged from the
bacterium. Spinosad is a complex  molecule  that requires a pathway of
enzymes and their genes for  its production. Pathways of that type are
not readily incorporated into the genomes of  crop plants.Nevertheless,
technology can move swiftly and it is best to say never say never.
How about spraying bacterial spores to release Spinosad (like the Bt
product Dippel)? I understand that  spinosad bacterium was first
isolated from the soil of a  brandy distillery in Europe but soon
recovered from alcoholism :-)
While Bt is stored in crystals in its spores, spinosad needs to be
released from filaments that may not thrive  on leaves.
In the immediate future we can probably depend on fermentation to
produce the insecticide.
Joe Cummins

Chuck Benbrook wrote:

        The original formulation of spinosad was registered for cotton
and
some vegetables, and was called SpinTor or Tracer.  It contained inert
ingredients not acceptable by IFOAM and most organic certifiers --
that is
why it does not show up on the IFOAM list.  In response to popular
demand,
Dow AgroSciences invested a considerable sum -- I have no idea but I bet
millions -- in coming up with an effective, stable formulation with OMRI-
and USDA-NOP-acceptable inerts.  The new organic formulation is called
Entrust; it has been reviewed by the USDA-NOP and OMRI and found to be a
non-synthetic product, and hence does not need approval by the NOSB-NOP
(being of natural origin).

        Spinosad is a very good biopesticide.  It fits great in IPM
programs and is extremely important as a thrips and whitefly material
where
tomatoes, peppers, and other veggies are grown.  It is highly toxic to
bees, however, so must be used with great care in areas where/when
bees are
foraging.  It is also highly toxic to certain aquatic invertebrates, but
since it is applied at very low rates/acre in mostly dry areas, and is
reasonably expensive, runoff is not a major isse.

        There are two big issues/challenges Saneters should be aware
of.  First, spinosad is a pretty big, stable molecule and can be
sprayed up
to just days before harvest -- which is good, in that farm workers,
pickers, and consumers are not getting exposed to OP, carbamate and other
much nastier insecticides.  But spinosad does and will show up as
residues,
and hence any company or ecolabel program based on a "no detectable
residue" claim could stop farmers from using it.

        Second, resistance management is a major concern with
spinosad.  To its credit, Dow AgroScieneces devotes considerable
attention/directions to resistant management on spinosad product
labels.  I
have a piece on the unique challenges faced by organic farmers in
managing/avoiding resistance to spinosad coming out in the next American
Vegetable Grower magazine.  That short article alerts the organic
community
to some of the unique resistance management issues surrounding
spinosad and
urges vigilance.  It would be a tragedy to undermine the efficacy of this
important new biopesticide.

_________________________________________________________________

Charles Benbrook         Ag BioTech InfoNet
<http://www.biotech-info.net>
Benbrook Consulting Services  CU FQPA site <http://www.ecologic-ipm.com>
5085 Upper Pack River Road            IPM site <http://www.pmac.net>
Sandpoint, Idaho  83864
Voice: (208)-263-5236
Fax: (208)-263-7342
E-mail: <benbrook@hillnet.com>

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