ABSTRACT
The International Union of Pure and Applied Chemistry (IUPAC) recommends that a pesticide may be dened as “a substance intended to kill pests: in common usage, any substance used for controlling, preventing, or destroying animal, microbiological, or plant pests” [1, p. 2123]. Pesticides are grouped according to their target organism; for example, rodenticides control rodents, insecticides control insects, fungicides control the growth of fungi, and herbicides control weeds. However, as shown in Figure 10.1, herbicides are extensively used and constituted 40% and about 50% of the total pesticides consumed globally and in the United States in 2007, respectively. Among the 250,000 plant species in the world, only 0.1% is wearisome enough to be termed weeds [2]. Weeds are a major economic problem in crop production because they cause yield loss, reduction in crop quality, show allelopathy, and act as a host of pests and diseases [2-4].
