Comparing conventional and biotechnology-based pest management.

Pest management has changed dramatically during the past 15 years by the introduction of transgenes into crops for the purpose of pest management. Transgenes for herbicide resistance or for production of one or more Bt toxins are the predominant pest management traits currently available. These two traits have been rapidly adopted where available because of their superior efficacy and simplification of pest management for the farmer. Furthermore, they have substantially reduced the use of environmentally and toxicologically suspect pesticides while reducing the carbon footprint of pest management as reduced tillage became more common, along with fewer trips across the field to spray pesticides. The most successful of these products have been glyphosate-resistant crops, which cover approximately 85% of all land occupied by transgenic crops. Over-reliance on glyphosate with continual use of these crops has resulted in the evolution of highly problematic glyphosate-resistant weeds. This situation has resulted in some farmers using weed management methods similar to those used with conventional crops. Evolution of resistance has not been a significant problem with Bt crops, perhaps because of a mandated resistance management strategy. Transgenic crops with multiple genes for resistance to different herbicides and resistance to additional insects will be available in the next few years. These products will offer opportunities for the kind of pest management diversity that is more sustainable than that provided by the first generation of transgenic crops.