A history of weed control in the United States and Canada—a sequel

The weed science discipline has changed significantly since 1970. New herbicides have been introduced, many herbicide-resistant weeds have been documented, herbicide-resistant crops have been introduced, federal laws affecting pesticides and weeds have been modified, the number of companies discovering and developing herbicides has been drastically reduced, basic studies on weed biology have received more emphasis, and integrated methods of controlling weeds with nonchemical as well as chemical methods have received increasing attention.