Abstract

Weeds, ie, unwanted plants, reduce crop yields and quality. Of the many approaches used to control weeds, the use of chemical herbicides is considered the most effective and efficient. Herbicides are a critical factor in agricultural productivity and represent a significant economic input in crop production. This review discusses herbicide mode of action, environmental fate, and chemistry, as well as the historical perspectives and future trends in herbicide development. Topics addressed include analytical methods, allelopathy and natural products, biological control, carcinogenicity, herbicide degradation, leaching, sorption, volatilization, movement in soil, enzyme and biosynthesis inhibition, free-radical induction, photosynthesis and pigment bleaching, plant growth regulators, seed safeners, water quality, and weed seeds. Primary herbicide groups include acid amides, amino acid analogues, aliphatic carboxylic acids, benzonitriles, bipyridiniums, carbamates, dinitroanilines, diphenyl ethers, imidazoles, inorganic and metallorganic compounds, mycoherbicides, phenoxy acids, phenoxyalkanoic acids, pyridines, pyridazones, phthalics, sulfonylureas, thiocarbamates, triazines, and ureas. Miscellaneous herbicides include acrolein, cinmethylin, clethodim, clomazone, ethofumesate, sethoxydim, and tridiphane. A list of herbicide, agrichemical, and toxicology databases is provided.