Table I. History of chemical weed control innovations.
Post, Postemergence application; Pre, preemergence application, based on data from Cremlyn (1991), Worthington and Hance (1991), Büchel et al. (1977), Herbicide Resistance Action Committee (www.hracglobal.com), and others.
| MoA, Target Site | Chemical Family | Examples | Use | Earliest Reports |
|---|---|---|---|---|
| Unspecific | Inorganic herbicides | H2SO4, Cu2SO4, FeSO4, NaAsO2 | Total | 1874 |
| Uncouplers | Dinitrophenoles | dinitro-ortho-cresol | Post, dicots | 1934 |
| Auxins | Aryloxyalkanoic acid derivatives | 2,4-Dichlorophenoxyacetic acid | Post, dicots in cereals | 1942 |
| Microtubule organization | Arylcarbamates | Propham, chloropropham | Pre, monocots in various crops | 1946 |
| Lipid synthesis | Chloroaliphatic acids | TCA, dalapon | Pre, monocots in various crops | 1947 |
| Thiocarbamates | EPTC, triallate | Pre, monocots and dicots in various crops | 1954 | |
| PSII | Arylureas | Monuron, diuron, isoproturon, linuron | Pre and Post, monocots and dicots in various crops | 1951 |
| 1,3,5-Triazines | Atrazine, simazine | Pre and Post, broad spectrum in corn | 1952 | |
| Pyridazines | Chloridazon | Pre, dicots in sugar beet | 1962 | |
| Uracils | Bromacil, terbacil, lenacil | Soil applied, broad spectrum in various crops | 1963 | |
| Biscarbamates | Phenmedipham | Post, dicots in sugar beet | 1968 | |
| 1,2,4-Triazinones | Metribuzin | Pre in soybean | 1971 | |
| Very-long-chain fatty acid biosynthesis | Chloroacetamides | Allidochlor, alachlor | Pre, monocots and dicots | 1956 |
| PSI | Bipyridyliums | Diquat, paraquat | Nonselective | 1958 |
| Protoporphyrinogen oxidase | Diphenyl ethers | Nitrofen, acifluorfen | Pre and Post, various crops | 1960 |
| Oxadiazoles | Oxadiazon | Rice, nonselective | 1969 | |
| Microtubule assembly | Dinitroanilines | Trifluralin, pendimethalin | Pre against monocots and dicots | 1960 |
| Cellulose biosynthesis | Nitriles | Dichlobenil | Plantations | 1960 |
| 5-Enolpyruvylshikimate 3-phosphate synthase | Glys | Glyphosate | Post, nonselective | 1971 |
| Phytoene desaturase | Pyridazinones | Norflurazon | Pre and Post in cotton | 1973 |
| ACCase | Aryloxyphenoxy propanoates | Diclofop, fluazifop | Post, grasses | 1975 |
| Cyclohexane diones | Alloxydim, sethoxydim | Post, grasses | 1976 | |
| Gln synthetase | Glufosinate | Nonselective | 1981 | |
| AHAS or ALS | Sulfonylureas | Chlorsulfuron, metsulfuron | Monocots and dicots in various crops | 1982 |
| Imidazolinones | Imazapyr, imazethapyr | Nonselective or selective in soybean | 1983 | |
| Pyrimidinyl benzoates | Bispyribac sodium | Rice | 1994 | |
| HPPD | Pyrazolynate, sulcotrione | Various crops, monocots and dicots | 1984 |