Transgenic Insecticidal Corn: Beyond Insecticidal Toxicity to Ecological Complexity

Many researchers have hailed transgenic insecticidal crops—plants modified to produce insecticidal proteins derived from genes of the bacterium Bacillus thuringiensis (Bt)—as the most important technological advancement in insect pest management since the development of synthetic insecticides (Vaeck et al. 1987, Koziel et al. 1993, Perlak et al. 1990, 1993). At least 18 transgenic insecticidal crops have been field-tested in the United States, and three (corn, cotton, and potato) have been widely planted (andow and Hutchison 1998, Federici 1998, Gould 1998, USDA 1999). But as the commercial availability of these crops has grown, so too has controversy over how to assess and manage the risks posed by this method of pest control. The widespread planting of millions of hectares of transgenic crops with high levels of insecticidal proteins raises concerns that pest populations might develop resistance to Bt toxins and that food webs might be disrupted (Gould 1998, McGaughey et al. 1998, Marvier 2001). Indeed, the US Environmental Protection Agency (EPA) requires industry to maintain populations of susceptible (nonresistant) insect pests to slow development of resistant populations. Nor are concerns limited to the United States: Anxiety over the safety of food and products derived from transgenic crops have created tensions among international trading partners (Balter 1997, Butler and Reichhardt 1999, Masood 1999).