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ORGANIC 4UM
May 25, 1999
This paper appeared in Science last week. The point of this paper is
that in order for the pest, the European Corn Borer to remain
susceptible to Bt the organism must have recessive traits (genes) for
the resistance and must have the following conditions when using the
proposed resistance management strategy for Bt maize: the
high-dose/refuge strategy which requires that plant tissue be very
toxic so that heterozygotes for resistance are killed, (ii) that the
resistance alleles be very rare, and (iii) that susceptible insects are
within an effective mating distance of resistant insects. The
high-dose/refuge strategy (a local non Bt corn stand and non exposed
insects for mating with) would not be useful for resistance management
if the trait is dominant; it's resistance genes must be recessive. In
this case the European Corn Borer was found to exhibit resistance to Bt
toxin in a dominant genetic manner. In contrast, the inheritance of
resistance to Bt in most other insects is controlled by recessive genes.
The proposed stratgy that the GMO companies are using for the possible
low appearance of resistance in some insects for Bt resistance is
severly flawed!
Abstract: Science 284: 965-967, 1999.
Inheritance of Resistance to Bacillus thuringiensis Toxin (Dipel ES) in
the European Corn Borer
F. Huang, 1 L. L. Buschman, 1 R. A. Higgins, 1* W. H. McGaughey 2
Resistance in the European corn borer, Ostrinia nubilalis (Hübner), to a
commercial formulation of Bacillus thuringiensis (Bt) Berliner toxin,
Dipel ES, appears to be inherited as an incompletely dominant autosomal
gene. This contrasts with the inheritance of resistance to Bt in other
insects, where it has usually been characterized as a recessive trait.
The proposed high-dose/refuge strategy for resistance management in Bt
maize depends on resistance being recessive or partially recessive.If
field resistance turns out to be similar to this laboratory resistance,
the usefulness of the high-dose/refuge strategy for resistance
management in Bt maize may be diminished.
1 Department of Entomology, Kansas State University, Manhattan, KS
66506, USA.
2 U.S. Department of Agriculture, Agricultural Research Service Grain
Marketing and Production Research Center,
1515 College Avenue, Manhattan, KS 66502, USA (retired).
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