Resistance can and has evolved to all forms of pest management, including chemical, biological, and cultural tools, and is not a unique concern for biotech-derived crops. When resistance does occur within insect populations, this is an economic issue for growers because they need to identify and use other types of insect pest control measures in order to continue producing their crop. However, the development of resistance in an insect or weed population has no direct effect on the environment because the balance of evidence shows organisms behave the same as they did prior to being exposed to that particular pest control strategy. With the case of GM crops, however, the indirect effect on the environment may be important. Insect resistant and herbicide tolerant GM crops allow the more targeted use of milder insecticides and herbicides to produce the same crop yield and so insect or weed resistance may require the grower to shift back to using more or stronger crop protection products. For this reason, the industry has set up stewardship plans and guidelines to help slow the development of resistance in both insects and weeds.
For more information on this topic, please refer to: www.croplife.org/Insect_resistance_management.