Status Report on Bt-Transgenic Corn Technologies
The last two weeks have seen a flurry of activity in the regulatory arena
in the United States regarding Bt-transgenic corn varieties and technology.
Key developments are noted herein and discussed, information sources are
identified, and questions raised.
Bt Corn for ECB Control
For the Bt corn varieties on the market today, the EPA released the week
of January 10th the agreement with industry re changes in resistance
management plans applicable for crop year 2000 for European corn borer
(ECB) and other target insects. The changes are modest relative to what
was required in 1999 and what had been proposed by the industry coalition
via the National Corn Growers Association. For extensive discussion of
Bt-corn for ECB control and resistance issues and links to many pertinent
documents, see the section on Ag BioTech InfoNet on the June 1999 EPA-USDA
workshop on this topic (go to
<www.biotech-info.net/Bt_corn_resist_mgmt.html>).
In press reports the last few days, some in the environmental community
have labelled this recent EPA action as "a step in the right direction."
Other biotech critics view anything short of cancellation, or a
"moratorium," as a "defeat" and have criticized those acknowledging that
some progress has been made. Such snipping is not constructive and are,
at best, a distraction.
My view is that the important decisions by EPA lie ahead (and should be
the focus of debate) -- Whether to extend the conditional ECB-Bt corn
registrations beyond crop year 2000; If they are extended, on what terms?;
and, What to do about the new applications for Bt-transgenic corn
engineered to control the corn rootworm complex of insects? This later is,
in many respects, the most significant biotechnology EPA has yet to review
if "significance" is judged by the scale of potential risks, benefits and
economic impacts. Decision criteria and rules, i.e. precedents set in the
case of Bt for ECB control will obviously factor prominently in the review
of the new Bt-corns for rootwrom control.
On the ECB-Bt front, there was virtually no chance that the EPA would pull
the plug on Bt corn in crop year 2000. Despite the fact clear concerns
have been raised, as a matter of law the agency lacked solid enough
justification to do so, on both the resistance and Monarch fronts. To the
extent that there is a risk of resistance emerging, the changes in
resistance management in crop year 2000 will do little to mitigate it.
Depending on how the changes and information gathering provisions are
implemented, the agreement might accelerate the process of documenting
problems in the field, which might then trigger more robust regulatory
actions.
The much more critical EPA decision-point will be reached in a few months
-- the decision to continue for another year the existing conditional
registrations. The conditional registrations sanctioning use of today's
Bt corn varieties lapse in early 2001. Unless they are extended, little or
no Bt corn for ECB control could be planted in crop year 2001. The
decision to extend the conditional registrations is a much more definitive
statement of EPA views re this technology than the just announced tinkering
with ECB resistance management plans. Based on its own regulations, EPA
should not extend the conditional registrations if any of the initial
conditions have still not been satisfied. The core condition was and
remains an effective, science-based resistance management plan. So the
core issue boils down to -- Can the agency defend a judgement later this
winter or in the early spring that the current, or further modified
resistance management plans will "work"? A related question -- what does
"work" mean?
There are a number of critical technical and policy oriented questions
that need to be pursued in response to the latest set of conditions EPA has
imposed for crop year 2000. More detailed discussion of these changes will
be forthcoming soon. Any responses from the grower, scientific, NGO
communities re the latest EPA action are not likely to change the rules of
the game for crop year 2000, but could significantly shape the new
conditions EPA imposes if the agency chooses to extend the conditional
registrations to allow another year of planting of these varieties in crop
year 2001.
Given the scientific evidence that has emerged of late, the issue is not
whether resistance will emerge. Two key issues loom: is preserving the
efficacy of conventional foliar Bt insecticides important enough reason to
stop using the technology? Thus far, EPA clearly does not consider
resistance an adequate concern or reason to deny the registration.
This decision is consistent with past policy and decisions on essentially
all ecological impacts of pesticides regulated by EPA under the FIFRA
statute (which, of course, also governs decisions on plant pesticides like
Bt-corn). EPA rarely if ever cancels an existing registration, or refuses
to approve a new application solely or largely on the grounds of ecological
impacts. Instead, the agency tries to mitigate ecological risks by
imposing various risk reduction measures. If EPA finally says "NO" to
American Cyanamid on its application for registration of chlorfenapyr
(Pirate), it will be the first time in history, as far as I know, that EPA
has denied a new registration largely because of ecological effects (in
this case, avian impacts; see recent SAP meetings and reports on this
chemical via <www.epa.gov/pesticides>, go to SAP, look for the sessions on
chlorfenapyr). If anyone knows of an exception to this statement (a
registration application denied largely because of ecological concerns),
please enlighten me.
Assuming EPA continues to believe resistance (and non-target Lepidopteran,
e.g Monarch, effects) are not adequate reason to deny the extension of the
ECB-corn conditional registrations, then a second cluster of issues emerges
--
What is the agency role in requiring and shaping resistance management
plans?
Whose job is it to assure they are credible and science based, and updated
as new information emerges?
Whose job is it, and with what authority and resources, are resistance
management requirements to be enforced? Ditto, who will pay for and enforce
the remedial actions called for in the EPA-established requirements for
crop year 2000 when/if evidence of resistance is found?
Who will shape, pay for, oversee, and interpret the applied field research
needed to monitor whether resistance management plans are working?
Who (if not EPA) will make the judgement that the resistance management
plans have failed? How will this judgement be made (and defended against
inevitable challenges) in time for remedial actions to be taken to avoid
the emergence of stable resistance genes in ECB populations?
Who, if anyone, will pay for the harm suffered by those who have never
used the technology but lose Bt insecticides as part of their IPM programs?
Bt Corn for Rootworm Control
Several posts in the last month have alerted people to the emergence of a
new generation of Bt-transgenic corn varieties engineered to control the
corn rootwrom complex of insects. In this case, Bt tenebrionis will be
expressed in corn root systems and through root exudates.
Much will be at stake as EPA considers this technology. Monsanto has
submitted a request for an Experimental Use Permit (EUP) and full
registration application for Cry3Bb protein toxin. We have developed a new
section on Ag BioTech InfoNet to present scientific information relative to
this new technology and to help people understand the consequences of the
decisions EPA will make. To access this material, go to --
http://www.biotech-info.net/rootworm.html
As promised, we have posted the excellent and timely paper by Dr. Mike
Gray, the corn IPM specialist from the Univ. of Illinois, on transgenic
corn varieties for rootworm control. This paper was delivered Jan. 5, 2000
at the Crop Protection Technology Conference on campus, and is posted with
permission from the meeting sponsors.
Thus far we have relatively few items posted in this section but we expect
it to grow quickly. We will add links to land grant resources on the
biology of the corn rootworm and the efficacy of various IPM strategies and
systems for corn rootworm control. We will post soon the original
Monsanto patent covering Bt.t gene constructs. If people are aware of
other relevant Monsanto, Dow AgroSciences, Mycogen, Pioneer or other
patents, please alert me and if possible, e-mail an electronic copy.
If you are aware of pertinent information Bt-corn, ECB, or corn rootworm
information that should be posted on the page, or linked to, please send a
note to me at <benbrook@hillnet.com>. I am particularly interested in
technical information on the gene constructs used to develop Cry3Bb corn,
or other Bt-transgenic varieties for rootworm control. Thanks for any help
provided.
Chuck Benbrook
Charles Benbrook CU FQPA site www.ecologic-ipm.com
Benbrook Consulting Services Ag BioTech InfoNet www.biotech-info.net
5085 Upper Pack River Road IPM site www.pmac.net
Sandpoint, Idaho 83864
208-263-5236 (Voice) 208-263-7342 (Fax)
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