In the case of transgenic corn the toxin gene comes from Bacillus thuringiensis var. If eaten by a susceptible insect, the toxin damages the gut lining and the insect becomes inactive, stops feeding and will die from both the effects of starvation and tissue damage.
Death occurs within a few days to a week.
Controlling insects through the use of transgenic plants has raised some concern among scientists, growers and others about how the potentially high selection pressure from these toxins will be expressed in the European corn borer populations. At issue is whether European corn borer or other targeted pests will become resistant to the Bt toxin in the future since the gene will be used in more crops and therefore acres that have engineered crops on them will increase. Genetically engineered crops that contain the Bt toxin genes have the potential to reduce pesticide usage and thereby lower the environmental and human health costs of food production and hopefully lower production costs. For these reasons we must develop strategies to avoid or prolong the development of resistant ECB populations. Target Pests Bt var.