ABSTRACT
The dose of herbicide applied to control weeds has been decreasing since 1985 in large part due to the high unit activity of newly introduced herbicides. There are many excellent options for controlling weeds in major agronomic crops such as rice, cereals, maize, and soybeans. Nearly all herbicides released by chemical company research groups since 1985 inhibit one of only three enzymes; acetolactate synthase (ALS), acetyl-coenzyme A carboxylase (ACCase), and protoporphyrinogen oxidase. Herbicide-resistant crop (HRC) technology can permit the use of the most environmentally sound, low use rate, herbicides in crop production, which is now not possible due to sensitivity of the crop to the herbicide. The use of herbicides on HRCs should not require any additional regulations. In the US, for example, there are currently precise regulations for registering an herbicide for the use on a new crop with the Environmental Protection Agency (EPA) under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).
