Table 1.

Global introduction of herbicide site of action groups (adapted from Heap [9]; WSSA: Weed Science Society of America system used in the USA and Canada; HRAC: Herbicide Resistance Action Committee system used in all other countries except Australia, which has its own system).

Decade	Site of Action *	Example	WSSA	HRAC	Australia
1930s	Uncouplers (membrane disruption)	Dinoterb	24	M	Z
1940s	Synthetic auxins	2,4-D	4	O	I
	Auxin transport inhibitors	Diflufenzopyr	19	P	P
	Mitosis inhibitors	Propham	23	K2	E
1950s	Microtubule assembly inhibitors	Trifluralin	3	K1	D
	PS-II inhibitors	Atrazine	5	C1	C
	PS-II inhibitors (ureas and amides)	Chlorotoluron	7	C2	C
	Lipid inhibitors	Triallate	8	N	J
	Carotenoid biosynthesis inhibitors	Amitrole	11	F3	Q
	Nucleic acid inhibitors	MSMA	17	Z	Z
	PS-I electron diverters	Paraquat	22	D	L
1960s	PS-II inhibitors (nitriles)	Bromoxynil	6	C3	C
	PPO inhibitors	Oxyfluorfen	14	E	G
	VLCFA inhibitors	Metolachlor	15	K3	K
	Lipid inhibitors	Ethofumesate	16	N	J
	DHP synthase inhibitors	Asulam	18	I	R
	Cellulose inhibitors	Dichlobenil	20	L	I,O,Z
1970s	ACCase inhibitors	Diclofop	1	A	A
	ALS inhibitors	Chlorsulfuron	2	B	B
	Cell elongtion inhibitors	Difenzoquat	8	Z	Z
	EPSPS inhibitors	Glyphosate	9	G	M
	Glutamine synthase inhibitors	Glufosinate	10	H	N
	Carotenoid biosynthesis inhibitors (PDS)	Diflufenican	12	F1	F
	Antimicrotubule mitotic disrupters	Flamprop	25	Z	Z
1980s	DOXP inhibitors	Clomazone	13	F4	Q
	Cellulose inhibitors	Dichlobenil	21,26	L	I,O,Z
	HPPD inhibitors	Isoxaflutole	27	F2	H

* Abbreviations: ACCase: acetyl-CoA carboxylase; ALS: acetolactate synthase; DHP: dihydropteroate; DOXP: 4-deoxy-D-xylulose-5-phosphate synthase; EPSPS: 5-enolpyruvlshikimate-3-phosphate synthase; HPPD: hydroxyphenyl-pyruvate-dioxygenase; PDS: phytoene desaturase; PPO: protoporphyrinogen oxidase; PS: photosystem; VLCFA: very long chain fatty acid.