A herbicide is a pesticide used to kill unwanted plants. Selective herbicides kill certain targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often based on plant hormones.
Herbicides, also commonly known as weedkillers, are substances used to control unwanted plants. Selective herbicides control specific weed species while leaving the desired crop relatively unharmed.
Although herbicides are designed to target plants, they can also be toxic to humans and wildlife. Herbicides vary greatly in their environmental impact, and more specifically, their toxicity and persistence in the environment.
Importance of herbicides
Herbicides are chemicals used to manipulate or control undesirable vegetation. Herbicide application occurs most frequently in row-crop farming, where they are applied before or during planting to maximize crop productivity by minimizing other vegetation.
Examples of contact herbicides are diclofop, dinoseb, diquat, and paraquat. Certain contact herbicides, like diquat and paraquat, are deactivated by soil particles. They must be mixed with clear water and applied directly to the vegetation.
Glyphosate—known by many trade names, including Roundup—has been the most widely used herbicide in the United States since 2001. Crop producers can spray entire fields planted with genetically engineered, glyphosate-tolerant (GT) seed varieties, killing the weeds but not the crops.
All chemicals, including herbicides, are potentially hazardous to human health. However, a basic principle of toxicology is that "the dose makes the poison".
Herbicides are used to control undesired plants on farms, in commercial forests, and on lawns and managed landscapes. Herbicides are sometimes applied directly to surface water for aquatic weed control.