Chemical Approaches to Weed Management
Since at least the mid 1800s, humans have used a variety of chemicals, including copper salts, iron sulfate, and sulfuric acid, as herbicides to control unwanted vegetation. However, modern chemical weed management began with the discovery of the phenoxy herbicides. This discovery ushered in the modern era of chemical weed management [47,72]. Modern selective chemical management of weeds increased rapidly during the 1950s and 1960s, because it was extremely successful and cost effective. This success and cost effectiveness is best illustrated by the fact that selective chemical management of unwanted vegetation is now used on over 95% of the agronomic hectarage in the United States.