Table 8-15.  Resistance risk category, herbicide family designation, mechanism of action, and WSSA
resistance management grouping for commonly used herbicides.
Risk Category	Herbicide	Mechansim of	WSSA Group1	Common	Trade
	Family	Action		Names	Names
High	Imidazolinone	Inhibit ALS; interfere with amino acid synthesis	2	imazamox	Raptor
				imazapic	Cadre
				imazaquin3	Scepter
				imazethapyr3	Pursuit
				imazethapyr + imazapyr	Lightning
	Pyrimidinylthio-benzoate	Inhibit ALS; interfere with amino acid synthesis	2	pyrithiobac	Staple
	Sulfonylurea	Inhibit ALS; interfere with amino acid synthesis	2	chlorimuron3	Classic
				chlorimuron + thifensulfuron	Synchrony STS
				halosulfuron	Permit
				nicosulfuron3	Accent
				primisulfuron	Beacon
				primisulfuron + prosulfuron	Exceed
				prosulfuron	Peak
				rimsulfuron3	Matrix
				rimsulfuron + thifensulfuron	Basis
				tribenuron	Express
				tribenuron + thifensulfuron	Harmony Extra
				thifensulfuron	Pinnacle
	Triazolopyrimidine	Inhibit ALS; interfere with amino acid synthesis	2	chloransulam	FirstRate
				diclosulam	Strongarm
				flumetsulam3	Python
				chloransulam + flumetsulam	Frontrow
	Aryloxyphenoxy propionate	Inhibit ACCase, interfere with lipid synthesis	1	diclofop	Hoelon
				fenoxaprop + fluazifop	Fusion
				fluazifop3	Fusilade DX
				quizalofop	Assure II
	Cyclohexanedione	Inhibit ACCase, interfere with lipid synthesis	1	clethodim3	Select,
					Conclude XTRA G
				sethoxydim3	Conclude G, Conclude Xtra G, Poast, Poast Plus, Prestige
Moderate	Dinitroaniline	Inhibit microtubule assembly, interfere with cell division	3	benefin	Balan
				ethalfluralin	Curbit, Sonalan
				pendimethalin3	Pentagon, Prowl
				trifluralin3	Treflan, Tri-4, Trilin, Trifluralin2
	Organoarsenical	Unknown	17	DSMA	Many brands
				MSMA	Many brands
	Triazine	Inhibit  photosystem II; lipid peroxidation; membrane disfunction	5	ametryn	Evik2
				atrazine3	AAtrex2
				atrazine + cyanazine	Extrazine II
				cyanazine	Bladex, Cy-Pro
				prometryn	Caparol, Cotton-Pro
				simazine	Princep2
	Triazinone	Inhibit photosystem II; lipid peroxidation; membrane disfunction	5	metribuzin3	Lexone, Sencor
Low	Acetamide	Unknown	15	napropamide	Devrinol
	Amino acid derivative	Inhibit glutamine synthase; ammonia accumulation and membrane disruption	10	glufosinate3	Liberty
		Inhibit EPSP synthase, interfere with amino acid synthesis	9	glyphosate	Roundup Ultra2
				sulfosate	Touchdown
	Benzothiadiazole	Inhibit photosystem II; lipid peroxidation; membrane disfunction	6	bentazon3	Basagran
	Benzoic acid	Synthetic auxin; uncontrolled cell division and growth	4	dicamba3	Banvel, Clarity, Distinct
	Bipyridilium	Inhibit photosystem I; lipid peroxidation; membrane destruction	22	paraquat	Gramoxone Extra, Starfire
	Chloroacetamide	Unknown	15	acetochlor3	Harness, Surpass, TopNotch
				alachlor3	Lasso, Micro-Tech,
					Partner
				dimethenamid3	Frontier
				metolachlor3	Dual II,
					Dual II Magnum
	Diphenylether	Inhibit PPO; lipid peroxidation, membrane destruction	14	acifluorfen3	Blazer, Status
				fomesafen3	Reflex, Flexstar
				lactofen3	Cobra
				oxyfluorfen	Goal
	Isoxazolidinone	Diterpene inhibition; bleaching	13	clomazone	Command
	N-phenyl-phthalimide	Inhibit PPO; lipid peroxidation, membrane destruction	14	flumiclorac3	Resource
	Nitrile	Inhibit photosystem II; lipid peroxidation; membrane disfunction	6	bromoxynil	Buctril, Buctril 4EC
	Phenoxy	Synthetic auxin; uncontrolled cell division and growth	4	2,4-D3	Many brand names
				2,4-DB	Butoxone2, Butyrac
	Phenylpyridazine	Inhibit photosystem II; lipid peroxidation; membrane disfunction	6	pyridate	Tough
	Pyridazinone	Inhibit carotenoid synthesis; bleaching	12	norflurazon	Zorial
	Thiocarbamates	Inhibit lipid synthesis; interfere with cell division and growth	8	butylate	Sutan+2
				EPTC	EPTAM, Eradicane
				pebulate	Tillam
				vernolate	Vernam
	Triazolinone	Inhibit PPO; lipid peroxidation, membrane destruction	14	sulfentrazone3	Spartan
	Urea	Inhibit photosystem II; lipid peroxidation; membrane disfunction	7	diuron	Karmex2
				fluometuron	Cotoran, Meturon
				linuron	Lorox2
1 Weed Sciece Society of America group designation.  Each specific mechanism of action for herbicides has a distinct
number.  Use the risk categories and WSSA group number in selecting herbicide tank mixes and rotations for
resistance management.
2 Other trade names also available.
3 This active ingredient present in packaged herbicide mixtures and co-packs; see Table 8-16.