Herbicides

 A great advantage of chemical herbicides over mechanical weed control is the ease of application, which often saves on the cost of labour. Most herbicides are considered nontoxic to animals and humans, but they can cause substantial mortality of nontarget plants and the insects that depend on them, especially when applied aerially.

Modern herbicides are often synthetic mimics of natural plant hormones that interfere with the growth of the target plants. The term organic herbicide has come to mean herbicides intended for organic farming. Some plants also produce their own natural herbicides.