An article in the June 1995, Jour. of Economic Entomology by
George Kennedy and Mark Whalon, "Managing Pest Resistance to BT
Endotoxins: Constraints and Incentives to Implementation" sets forth in
detail the practical constraints that the BT-industry face in moving BT
transgenic seeds into the marketplace. Competitive pressures and
individual profit-maximizing behavior will work against adherence to
therotetical useful resistant management schemes.
The bottom-line of the articles is that resistance will happen,
but it can possibly be delayed a few years, if BT plants are used widely
in any area. But there seems no way for this outcome to be avoided;
there are no laws which say that private companies shall preserve the
pool of bt-susceptible genes in insects of concern. In fact, it is in
the best interests of some chemical companies to exploit Bt for maximum
profit while propritary protections in place, and when patents, other
protections are over, move on to the next technology, leaving the less
effective "generic" Bt market to others.
In the movement toward bio-intensive IPM, the ability and
willingness of farmers to work together in area-wide management programs
that alter pest habitat, movement, over-wintering success, etc will
grow. Part of such cooperative approaches will be resistance management
to reduced risk biochemicals, like Bt. Bt-trangenic plants violate the
basic principle of IPM/biocontrol -- spray (apply/deliver) pesticides
only where and as needed. Bt transgneic plants, as a marketable
technology, represent what is technically possible and appears likely to
return profits, not what makes sense from the perspective of society or
the farmer. The question now becomes what price will be paid as this
lesson is (re-) learned.