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Turfgrass Herbicides: Mode of Action and Resistance Management

Pawel Petelewicz, J. Bryan Unruh, and Ramon G. Leon

Target Audience

This document is a tool for turfgrass professionals, sod producers, golf course superintendents, athletic and sports fields managers, landscape managers, and extension specialists to help develop herbicide programs that reduce the risk of herbicide resistant weeds in turfgrass systems.

Introduction

Herbicides are the most efficacious tool for weed control in turfgrass. Many common and/or troublesome weeds are not adequately controlled for various reasons such as lack of access to efficacious active ingredients (AIs) and use restrictions to selected turf species. Weed species are also capable of adapting where these poorly controlled become more common. If not successfully controlled, these weeds can spread creating a cascade of environmental, management and economic issues. In addition, certain weeds have a high potential for developing resistant populations. One such weed is goosegrass [Eleusine inidica (L.) Gaertn.] which is a difficult to control annual grassy weed in most Florida turfgrass systems. Populations resistant to current industry standard herbicides such as prodiamine, oxadiazon, and metribuzin have been confirmed in various turfgrass settings.

For turfgrass managers, resistant populations lead to a further limitation of reliable control options. This may force managers to employ less efficacious chemistries, or overuse options still capable of providing satisfactory control, directly resulting in increased management costs. Alternative products can be significantly more expensive while less efficacious products often require more applications to achieve desired weed control. These strategies can also pose an elevated risk of turfgrass damage. While herbicide safeners and/or safening strategies could reduce the potential for turfgrass injury, they generate additional logistic issues and/or expenses and effects may be inconsistent.

Successfully preventing resistance problems requires a complete understanding of what herbicide resistance is, how it develops, and effective strategies for mitigation. To achieve this, it is also crucial to understand the general nature of herbicidal activity within a plant.

Herbicide Mechanism of Action and Herbicide Resistance Explained

The term mode of action (MoA) refers to the entire sequence of events occurring within the plant treated with an herbicide (including its uptake, translocation, and metabolism), from first contact until the death of the susceptible plant. The term mechanism of action (MOA) is more specific and applies to a particular chain of biophysical (e.g., electron flow inhibition, cell division disruption, protein binding) or biochemical (e.g., enzyme inhibition) processes which herbicide disrupts (e.g., by inhibition or over-stimulation). Although some herbicides may function via several MoAs, only one is considered principal, and is used to describe the herbicide’s effect on plant. There is also a term site of action which refers to a particular location within a cell where these processes occur (e.g., chloroplasts or particular photosystems in the case of photosynthesis, mitochondria in the case of respiration, nuclei in the case of mitosis, specific binding sites on a protein in the case of enzymes). Some confusion may arise as sometimes those three terms are incorrectly considered as interchangeable by individuals referring to the MoA, which is also used as one of the characteristics for herbicide classification. Being fundamental to proper herbicide resistance management, it is the MoA which is further discussed in this publication.

Herbicide resistance is commonly defined as “the inherited ability of a plant to survive and reproduce following exposure to a dose of herbicide normally lethal to the wild type”. A more current weed-specific definition describes herbicide resistance as “the evolved capacity of a previously herbicide-susceptible weed population to withstand an herbicide and complete its life cycle when the herbicide is used at its normal rate in an agricultural situation”. In both cases herbicide resistance, is distinct from herbicide tolerance which is described as the “ability of a plant to remain uninjured by a dose of an herbicide normally lethal to other plant species”.

Overall, while HR results from over-reliance on herbicides as a sole mean for weed control, herbicides do not induce any gene mutations resulting in herbicide resistance. Those occur naturally and spontaneously. Subsequently, herbicide resistance can be transferred between generations via sexual reproduction in plants producing seeds. Such risk is higher in weeds with an annual life cycle compared to perennial plants that do not rely completely on seed production (i.e., sexual reproduction) for persistence across multiple seasons.

Herbicide resistance usually develops where an individual herbicide or herbicides with the same MoA are used excessively. This occurs during continuous and repeated applications over extended periods of time (e.g., multiple seasons) as the primary control of particular weed species. Such an approach creates a high selection pressure on the targeted weed populations. In most cases, herbicide resistance is already present at very low levels (often <0.0001%). While susceptible plants are removed by the herbicide, the herbicide resistant individuals grow and reproduce and eventually become dominant. Also, weeds may evolve herbicide resistance to other herbicides within the same MoA. However, this is not the case with all MoAs.

Monoculture settings of perennial crops, such as turfgrass, additionally favor the development of herbicide resistant populations. In these situations, crop rotation does not occur, eliminating herbicide options with differing MoAs that would be used in rotational crops. Moreover, proven agronomic management practices that alleviate the risk for herbicide resistance development such as tillage and cultivation, cover cropping, and fallow periods cannot be employed in established turfgrass settings. Therefore, the use of herbicides to control weeds in turfgrass settings becomes a necessity.

Strategies for Reduction of HR Development Risk

Entities such as Weed Science Society of America (WSSA) and the Herbicide Resistance Action Committee (HRAC) have developed MoA-based herbicide classification systems to help end users better address arising herbicide resistance issues. In the past, there were differences between these individual systems (e.g., numerical coding in WSSA’s system, alphabetical coding in HRAC’s system). In 2020, the HRAC updated their classification system to capture new active ingredients and to reflect the current state of knowledge. Also, the classification was harmonized, and a transition was made from alphabetical (now referred to as ‘HRAC Legacy’) to numerical codes to ensure global sustainability of the system. A summary of MoA and their classification according to WSSA and HRAC is provided in Table 1, while a comprehensive list of herbicides that are registered for use in turfgrass and their respective MoA WSSA/HRAC groups is provided in Table 2. Alphabetical codes are no longer used in the U.S., thus are not included in this publication. Moreover, in effort to adopt responsible resistance management practices, CropLife International members have voluntarily committed to include MoA icons and WSSA/HRAC groups on all herbicide product labels (Figure 1).

Example of an herbicide product label with an icon indicating the herbicides’ mechanism of action (MoA) classification in Weed Science Society of America (WSSA) and Herbicide Resistance Action Committee (HRAC) harmonized system.
Figure 1. Example of an herbicide product label with an icon indicating the herbicides’ mechanism of action (MoA) classification in Weed Science Society of America (WSSA) and Herbicide Resistance Action Committee (HRAC) harmonized system.
Credit: undefined

There are several strategies designed to delay or prevent herbicide resistance development in weeds. The most practical and effective tactic is to rotate the use of herbicides with different MoAs. Simply put, if two herbicides have the same MoA number or code, regardless of different names or active ingredients, they affect weeds in the same way. As previously explained, frequent and repeated use of herbicides with the same MoA will increase the risk of herbicide resistance development. Conversely, using a diverse herbicide program that either rotates or combines herbicides with different MoAs will help delay the development of resistant weeds.

MoA rotation helps delay herbicide resistance because changing the MoA reduces the chances of survival and reproduction of herbicide resistant weeds. In simple terms, if a weed survives an herbicide application with one MoA because it is resistant, the problem can be controlled if the surviving weed is treated with an herbicide with a different MoA to which it has not become resistant.

As shown in Table 2, most herbicides for preemergence (PRE) control are inhibitors of microtubule assembly (Group 3) and mitosis inhibitors (Group 15), while postemergence herbicides are predominantly acetolactate synthase (ALS) inhibitors (Group 2). Although many turfgrass professionals base their weed management programs solely on Groups 3 and 2, it is critical that herbicides from other MoA groups be included also. To ensure that the most frequently used herbicides in turfgrass will continue being effective for a long time, herbicides with different MoAs should be included in weed management programs even if they are not as effective or require repeat applications to provide the desired level of control.

Example of groups that are useful for MoA rotation with microtubule assembly inhibitors (Group 3) and mitosis inhibitors (Group 15) in PRE programs in turfgrass:

  • Group 21 – inhibitors of cell wall synthesis at site B
  • Group 29 – inhibitors of cell wall synthesis at site C
  • Group 8 – inhibitors of lipid synthesis other than Acetyl CoA Carboxylase (ACCase) inhibitors
  • Group 14 (specific active ingredients) – oxadiazole family of protoporphyrinogen oxidase (Protox, PPO) inhibitors

Example of groups that are useful for MoA rotation with ALS-inhibitors (Group 2) in POST programs in turfgrass:

  • Group 27 – inhibitors of 4-hydroxyphenyl-pyruvatedioxygenase (4-HPPD)
  • Group 5 – inhibitors of photosynthesis at photosystem II (PSII) site A
  • Group 14 (specific active ingredients) – triazolinones family of PPO inhibitors
  • Group 4 – synthetic auxins
  • Group 6 – inhibitors of PSII site B

Example of groups which, due to their dual activity, could be considered for rotation in both PRE and POST programs in turf

  • Group 5 (specific active ingredients) – triazine family of PSII site A-inhibitors
  • Group 8 (specific active ingredients) – benzofuran family of inhibitors of lipid synthesis other than Acetyl CoA Carboxylase (ACCase) inhibitors
  • Group 3 (specific active ingredients) – benzamide family of microtubule assembly inhibitors
  • Group 14 (specific active ingredients) – N-phenylphthalimide family of PPO inhibitors
  • Group 30 – tyrosine aminotransferase inhibitors

There are two ways to rotate herbicides in turfgrass settings. The first is to rotate herbicide MoAs from year to year (Figure 2). For example, one could use a Group 21 PRE herbicide in the fall of year 1 and change to Group 3 PRE herbicide in the fall of year 2. Conversely, one could use Group 2 POST herbicide in year 1 and then switch to Groups 4 and 14 POST herbicides in year 2.

Example of mechanism of action (MoA) rotation within individual season and across years. MoA change from the preemergence (PRE) to postemergence (POST) applications as well as both PRE and POST herbicide MoA change from year to year.
Figure 2. Example of mechanism of action (MoA) rotation within individual season and across years. MoA change from the preemergence (PRE) to postemergence (POST) applications as well as both PRE and POST herbicide MoA change from year to year.
Credit: undefined

The second way is to rotate herbicides within a season (Figure 2). In this approach, the rotation cycle may apply to either individual applications or their entire sequences (i.e., initial application followed by supplemental applications as prescribed on the herbicide label). Overall, there are three possible scenarios applicable to this approach. In all of them, the tactic is to change the herbicide MoA to eradicate plants surviving previous application(s) which are often referred to as “escapes”. This approach is called the "double-knock down" strategy because weed control is based on two consecutive actions.

In the first scenario, one could apply a Group 21 PRE herbicide at the beginning of the season and switch to a Group 2 POST herbicide to kill plants that may still be emerging and were not prevented by the initial PRE application.

The second and third scenarios are similar to each other and often apply to environments with extended growing seasons, such as Florida’s. For example, one could use a Group 21 PRE herbicide prior to expected germination of a target weed and then perform a sequential, follow-up application. However, when residual efficacy of those treatments is expected to diminish, then one could switch to a Group 3 PRE herbicide to ensure no germination occurs later in the season. Similarly, when applying POST herbicides, MoAs should be rotated between 2 POST applications/sequences within same season to target the escapes from the initial application.

Another strategy is to use either tank-mixes or pre-mixes of various active ingredients containing different MoAs. There are also many pre-mix options available in the market, however, most contain 1 to 3 active ingredients from the same MoA group, which is not beneficial from an herbicide resistance management standpoint. The addition of certain active ingredients or even MoAs will broaden their efficacy on additional groups/species of weeds; however, they will not boost the efficacy on the target weed. Therefore, from an herbicide resistance management perspective, it is important that all components of either a tank-mix and/or a rotation program have the capacity to control the target weed.

Lastly, the turf’s own ability to outcompete other species is the key to both successful weed control and reduced herbicide resistance risk. A healthy, dense turfgrass enhances competitiveness against weeds and reduces their encroachment. To ensure successful weed control and to minimize herbicide resistant weed development, all of the strategies discussed should be combined with practices aimed to provide the best possible growing conditions for turfgrass along with proper sanitation practices to avoid reintroduction of problematic plants.

Table 1. Mechanism of action (MoA classification according to the Weed Science Society of America (WSSA) and the Herbicide Resistance Action Committee (HRAC) for selective preemergence (PRE) and postemergence (POST) herbicides registered for use in turfgrass.

HRAC WSSA

MOA Group

Chemical Family

Common Name[Active Ingredient(s)]

Activity

Example Product Trade Name(s)

Single MoA Compounds

Acetyl CoA Carboxylase (ACCase) Inhibitors

Standalones

1

Aryloxyphenoxy-propionates ('FOPs')

fenoxaprop-P

POST

Acclaim Extra

fluazifop-P-butyl

POST

Fusilade II, Ornamec 170, Ornamec Over-The-Top

Cyclohexanedione ('DIMs')

sethoxydim

POST

Segment, Segment II

Phenylpyrazoline ('DEN')

pinoxaden

POST

Manuscript

Acetolactate Synthase (ALS) or Acetohydroxy Acid Synthase (AHAS) Inhibitors

Standalones

2

Imidazolinones

imazapic

POST

Plateau

imazaquin

POST

Scepter T&O 70 WDG

Pyrimidinyl(thio)benzoates

bispyribac-sodium

POST

Velocity SG

pyrimisulfan

POST

Vexis

Sulfonylureas

flazasulfuron

POST

Katana

foramsulfuron

POST

Revolver

halosulfuron-methyl

POST

Halo 5WDG Select, Halo 75WDG Prime, Halo 75WDG Select, Halomax 75, Profine 75, Prosedge, Sandea, SedgeHammer, SedgeHammer+

imazosulfuron

POST

Celero

metsulfuron-methyl (MSM)

POST

Manor, MSM 250D, MSM 60, Omni Brand MSM 60 DF, Quali-Pro MSM Turf, Tide MSM 60 DF

rimsulfuron

POST

Rimsulfuron 25DF

sulfometuron-methyl

POST

Oust XP

sulfosulfuron

POST

Certainty, Creedent 75WDG

trifloxysulfuron-sodium

POST

Monument 75WG, Revolution

Triazolopyrimidines

florasulam

POST

Defendor

penoxsulam

POST

LockUp, Sapphire

Premixes

2

Sulfonylureas

metsulfuron-methyl (MSM)+ rimsulfuron

POST

Negate 37WG

POST

Sulfonylureas

sulfometuron-methyl+ metsulfuron-methyl (MSM)

POST

Oust XTRA

POST

Sulfonylaminocarbonyl-triazolinone+ sulfonylureas

thiencarbazone-methyl

+ foramsulfuron

+ halosulfuron-methyl

POST

Tribute Total

POST

POST

Sulfonylaminocarbonyl-triazolinone+ sulfonylureas

thiencarbazone-methyl

+ iodosulfuron-methyl-sodium

+ halosulfuron-methyl

POST

Celsius XTRA

POST

POST

Inhibitors of Microtubule Assembly

Standalones

3

Benzamide

pronamide

PRE/POST

Kerb 50-W, Kerb 50WP, Kerb SC T&O

Benzoic acid

DCPA

PRE

Dacthal Flowable, Dacthal W-75

Dinitroanilines

benefin

PRE

Balan 2.5G, Balan DF, Crabgrass Preventer

oryzalin

PRE

Dinitroaniline Surflan WDG, Harrier 4L, Oryzalin 4 A.S., Surflan AS Specialty

pendimethalin

PRE

Pendulum 2G, Pendulum 3.3 EC, Pendulum AquaCap, PRE-M 3.3 EC

prodiamine

PRE

Barricade 4FL

Pyridine

dithiopyr

PRE

Dimension 2EW, Dimension EC, Dimension Ultra 40WP

Premixes

3

Dinitroanilines

benefin+ oryzalin

PRE

Surflan A.S., Surflan XL 2G, XL 2G

PRE

Dinitroanilines

benefin+ trifluralin

PRE

Crabgrass Control 2% Team, Team 2G, Team Pro

PRE

Synthetic Auxins

Standalones

4

Benzoic acid

dicamba

POST

Banvel, Banvel 4S, Clash, Cruise Control, Diablo, Sterling Blue, Vanquish, Vision

Phenoxy carboxylic acids

2,4-D

POST

2,4-D Amine, 2,4-D LV 6, Barrage HF, Clean Amine, Hardball, Opti-Amine, Saber, Shredder 2,4-D LV4, Shredder 2,4-D LV6, Shredder Amine 4, Shredder E-99, Weedar 64, WEEDestroy AM40, Weedone LV4 EC

MCPA

POST

MCPA-4 Amine, MCPA ester 4

mecoprop-P (MCPP)

POST

MCPP-p 4 Amine, Mecomec 2.5

Pyridine carboxylic acids

clopyralid

POST

Lontrel T&O

fluroxypyr

POST

Vista XRT

triclopyr

POST

Triclopyr 4, Trycera, Turflon Ester, Turflon Ester Ultra

Quinoline carboxylic acid

quinclorac

POST

Drive 75DF, Drive XLR8, Eject 75DF, Quinclorac, Quinclorac 75DF, Quinclorac SPC 75DF, QuinPro Herbicide, Quintessential, Rook 4L

Two-way Premixes

4

Phenoxy carboxylic acids

 

2,4-D+ aminopyralid

POST

NativeKlean

 

POST

Phenoxy carboxylic acid

+ benzoic acid

2,4-D

+ dicamba

POST

On Deck

 

POST

Phenoxy carboxylic acid

2,4-D

+ dichlorprop (2,4-DP)

POST

Patron 170, Turf Weed & Brush Control

POST

Phenoxy carboxylic acid

+ pyridine carboxylic acid

2,4-D

+ triclopyr

POST

Aquasweep, Chaser, Chaser 2 Amine, Crossroad, Everett, Turflon II Amine

POST

Pyridine carboxylic acid

 

fluroxypyr

+ triclopyr

POST

Tailspin

 

POST

Pyridine carboxylic acid

 

triclopyr

+ clopyralid

POST

Confront, 2-D

 

POST

Three-way Premixes

4

Phenoxy carboxylic acid

+ benzoic acid

+ phenoxy carboxylic acid

2,4-D

+ dicamba

+ dichlorprop (2,4-DP)

POST

Brushmaster, Super Trimec

 

POST

POST

Phenoxy carboxylic acid

+ benzoic acid

+ pyridine carboxylic acid

2,4-D

+ dicamba

+ clopyralid

POST

Millenium Ultra 2,

 

POST

POST

Phenoxy carboxylic acid

+ benzoic acid

+ quinoline carboxylic acid

2,4-D

+ dicamba

+ quinclorac

POST

2DQ, Gordon's Trimec Crabgrass Plus Lawn Weed Killer,

Momentum Q, Quincept

POST

POST

Phenoxy carboxylic acid

+ pyridine carboxylic acid

+ benzoic acid

2,4-D

+ fluroxypyr

+ dicamba

POST

Elliptical, Escalade 2

 

POST

POST

Phenoxy carboxylic acid

+ pyridine carboxylic acid

+ pyridine carboxylic acid

2,4-D

+ fluroxypyr

+ halauxifen-methyl

POST

GameOn

 

 

POST

POST

Phenoxy carboxylic acid

+ phenoxy carboxylic acid

+ benzoic acid

2,4-D

+ mecoprop-P (MCPP)

+ dicamba

POST

3-D, Eliminate LO, Eliminate-D, EndRun, MEC Amine-D, Strike-3, Threesome, Three-Way, Trimec 1000, Trimec 899, Trimec 992, Trimec Bentgrass Formula, Trimec Classic, Triplet Low Odor, Triplet Selective, Triplet SF, TruPower2

POST

POST

Phenoxy carboxylic acids

 

 

2,4-D

+ mecoprop-P (MCPP)

+ dichlorprop (2,4-DP)

POST

Spoiler, Triamine

 

POST

POST

Phenoxy carboxylic acid

+ pyridine carboxylic acid

+ pyridine carboxylic acid

2,4-D

+ triclopyr

+ fluroxypyr

POST

Momentum FX2

 

 

POST

POST

Phenoxy carboxylic acid

+ pyridine carboxylic acid

+ benzoic acid

MCPA

+ fluroxypyr

+ dicamba

POST

Change Up

 

 

POST

POST

Phenoxy carboxylic acid

+ pyridine carboxylic acid

+ pyridine carboxylic acid

MCPA

+ fluroxypyr

+ triclopyr

POST

Battleship III

 

 

POST

POST

Phenoxy carboxylic acid

+ phenoxy carboxylic acid

+ benzoic acid

MCPA

+ mecoprop-P (MCPP)

+ dicamba

POST

Trimec Encore, Tri-Power

 

POST

POST

Phenoxy carboxylic acids

 

 

MCPA

+ mecoprop-P (MCPP)

+ dichlorprop (2,4-DP)

POST

Triamine II

 

 

POST

POST

Phenoxy carboxylic acid

+ pyridine carboxylic acid

+ phenoxy carboxylic acid

MCPA

+ triclopyr

+ dicamba

POST

Cool Power, Eliminate, Horsepower, Spurge Power, Three-Way Ester II

POST

POST

Phenoxy carboxylic acid

+ benzoic acid

+ quinoline carboxylic acid

quinclorac

+ dicamba

+ MCPP

POST

Onetime Herbicie

 

 

POST

POST

Inhibitors of photosynthesis at photosystem II site A

Standalones

5

Triazine

 

atrazine

PRE/POST

AAtrex 4L, AAtrex Nine-O, Atrazine 4L, Atrazine 90DF

simazine

PRE/POST

Princep 4L, Princep Liquid, Simazine 4L, Simazine 90DF, Sim-Trol 4L, Sim-Trol 90DF

Triazinone

 

metribuzin

POST

Sencor 75%

hexazinone

POST

Velpar 2L

Triazolinone

amicarbazone

POST

Xonerate, Xonerate 2SC

Inhibitors of photosynthesis at photosystem II site B

Standalones

6

Benzothiadiazinone

bentazon

POST

Basagran T&O

Nitrile

bromoxynil

POST

Broclean, Buctril, Buctril 2L, Buctril 4EC, Maestro 2EC, Maestro 4EC, MOXY 2E

Inhibitors of lipid synthesis; not ACCase inhibition

Standalones

8

Benzofuran

ethofumesate

PRE/POST

PoaConstrictor, Prograss, Prograss SC, Thrasher

Phosphorodithioate

bensulide

PRE

Bensumec 4LF, Betasan 3.6G, Pre-San 7G, Pre-San Granular 12.5G, ProTurf Weedgrass Preventer 8.5G, Weedgrass Preventer

Inhibitors of protoporphyrinogen oxidase (Protox, PPO)

Standalones

14

N-phenylphthalimide

flumioxazin

PRE/POST

SureGuard SC

Phenylpyrazole

pyraflufen-ethyl

POST

Octane 2% SC

Triazolinones

carfentrazone-ethyl

POST

Quicksilver T&O

sulfentrazone

POST

Aquesta 4F, Dismiss, Dismiss CA, Dismiss CA Turf, Dismiss Turf, Loyalty 75WDG, Spartan 4F

Oxadiazole

oxadiazon

PRE

Ronstar FLO, Ronstar G

Premixes

14

Triazolinones

 

carfentrazone-ethyl

+ sulfentrazone

POST

Dismiss NXT, Spartan Charge

POST

Mitosis Inhibitors

Standalones

15

Acetamide

napropamide

PRE

Devrinol 2G, Devrinol 50 WP, Ornamental Herb. 5G,

Chloroacetamides

dimethenamid-P

PRE

Tower

S-metolachlor

PRE

Pennant Magnum

Inhibitors of cell wall synthesis site B

Standalones

21

Benzamide

isoxaben

PRE

Gallery 75 Dry Flowable, Gallery S.C., Isoxaben 75WG

Inhibitors of 4-hydroxyphenyl-pyruvatedioxygenase (4-HPPD)

Standalones

27

Triketone

mesotrione

PRE/POST

Tenacity

Pyrazolone

topramezone

POST

Pylex

Inhibitors of cell wall synthesis site C

Standalones

29

Alkylazine

indaziflam

PRE

Specticle FLO, Specticle G

Tyrosine Aminotransferase

Standalones

30

unspecified

methiozolin

PRE/POST

PoaCure SC

Unknown MoA

Standalones

0

Organoarsenical

DSMA

POST

Ansar 8100, DSMA Liquid

MSMA

POST

MSMA 6 Plus, MSMA 6.6, TARGET 6 Plus, TARGET 6.6, Weed-Hoe

Multiple MoA Premixes

Groups 1 + 4

1

Aryloxyphenoxy-propionate ('FOP')

+ pyridine carboxylic acid

+ benzoic acid

fenoxaprop-P

+ fluroxypyr

+ dicamba

POST

Last Call

 

 

4

POST

4

POST

Groups 2 + 3 + 5

3

Dinitroaniline

+ imidazolinone

+ triazine

prodiamine

+ imazaquin

+ simazine

PRE

Coastal

 

 

2

POST

5

PRE/POST

Groups 2 + 4

2

Sulfonylaminocarbonyl-triazolinone

+ sulfonylurea

+ benzoic acid

thiencarbazone-methyl

+ iodosulfuron-methyl-sodium

+ dicamba

POST

Celsius WG

 

 

2

POST

4

POST

2

Sulfonylurea

+ benzoic acid

halosulfuron-methyl

+ dicamba

POST

Yukon

 

4

POST

Groups 2 + 4 + 14

2

Triazolopyrimidine

+ phenoxy carboxylic acid

+ benzoic acid

+ triazolinone

penoxsulam

+ 2,4-D

+ dicamba

+ sulfentrazone

POST

Avenue South

 

 

 

4

POST

4

POST

14

PRE/POST

Groups 2 + 14

2

Imidazolinone

+ triazolinone

imazethapyr

+ sulfentrazone

POST

Dismiss South, Sulfen Southern

14

PRE/POST

14

Triazolinone

+ sulfonylureas

sulfentrazone

+ metsulfuron-methyl (MSM)

PRE/POST

Blindside

2

POST

Groups 3 + 4

3

Dinitroaniline

+ quinoline carboxylic acid

prodiamine

+ quinclorac

PRE

Cavalcade PQ, LESCO Stonewall PQ

14

POST

Groups 3 + 14

3

Dinitroaniline

+ triazolinone

prodiamine

+ sulfentrazone

PRE

Echelon 4SC, various fertilizers with Echelon

14

PRE/POST

14

Oxadiazole

+ dinitroaniline

oxadiazon

+ prodiamine

PRE

Regalstar II, Regalstar G

3

PRE

Groups 3 + 15

3

Dinitroaniline

+ chloroacetamide

pendimethalin

+ dimethenamid-P

PRE

FreeHand 1.75G

15

PRE

Groups 3 + 21

3

Pyridine

+ benzamide

dithiopyr

+ isoxaben

PRE

Crew

21

PRE

3

Dinitroaniline

+ benzamide

trifluralin

+ isoxaben

PRE

Snapshot 2.5 TG, Snapshot DG

21

PRE

Groups 4 + 6

4

Phenoxy carboxylic acid

+ nitrile

2,4-D

+ bromoxynil

POST

Maestro D

 

6

POST

4

Phenoxy carboxylic acid

+ nitrile

MCPA

+ bromoxynil

POST

Maestro Advanced, Maestro MA

6

POST

Groups 4 + 14

4

Phenoxy carboxylic acid

+ phenoxy carboxylic acid

+ benzoic acid

+ triazolinone

2,4-D

+ mecoprop-P (MCPP)

+ dicamba

+ pyraflufen-ethyl

POST

RedZone 2

4

POST

4

POST

14

POST

4

Phenoxy carboxylic acid

+ pyridine carboxylic acid

+ benzoic acid

+ phenylpyrazole

2,4-D

+ triclopyr

+ dicamba

+ pyraflufen-ethyl

POST

4-Speed XT

4

POST

4

POST

14

POST

4

Phenoxy carboxylic acid

+ pyridine carboxylic acid

+ benzoic acid

+ phenoxy carboxylic acid

2,4-D

+ triclopyr

+ dicamba

+ MCPA

POST

Triad T Select

4

POST

4

POST

14

POST

4

Phenoxy carboxylic acid

+ phenoxy carboxylic acid

+ benzoic acid

+ triazolinone

2,4-D

+ dichlorprop (2,4-DP)

+ dicamba

+ carfentrazone ethyl

POST

SpeedZone Southern EW

4

POST

4

POST

14

POST

14

Triazolinone

+ phenoxy carboxylic acid

+ phenoxy carboxylic acid

+ benzoic acid

carfentrazone ethyl

+ 2,4-D

+ mecoprop-P (MCPP)

+ dicamba

POST

SpeedZone, SpeedZone EW, SpeedZone Lawn Weed Killer, SpeedZone Southern

4

POST

4

POST

4

POST

14

Triazolinone

+ phenoxy carboxylic acid

+ phenoxy carboxylic acid

+ benzoic acid

carfentrazone ethyl

+ MCPA

+ mecoprop-P (MCPP)

+ dicamba

POST

PowerZone, SpeedZone Ready-To-Use Lawn Weed Killer

4

POST

4

POST

4

POST

14

Triazolinone

+ quinoline carboxylic acid

carfentrazone

+ quinclorac

POST

SquareOne

4

POST

4

Quinoline carboxylic acid

+ triazolinone

+ phenoxy carboxylic acid

+ benzoic acid

quinclorac

+ sulfentrazone

+ 2,4-D

+ dicamba

POST

Q4 Plus

14

PRE/POST

4

POST

4

POST

14

Triazolinone

+ phenoxy carboxylic acid

+ phenoxy carboxylic acid

+ benzoic acid

sulfentrazone

+ 2,4-D

+ mecoprop-P (MCPP)

+ dicamba

PRE/POST

SureZone, Surge

4

POST

4

POST

4

POST

14

Triazolinone

+ quinoline carboxylic acid

sulfentrazone

+ quinclorac

PRE/POST

Solitare, Solitare WSL

4

POST

4

Pyridine carboxylic acid

+ triazolinone

+ phenoxy carboxylic acid

+ benzoic acid

triclopyr

+ sulfentrazone

+ 2,4-D

+ dicamba

POST

TZONE SE

14

PRE/POST

4

POST

4

POST

Groups 4 + 27

4

Phenoxy carboxylic acid

+ benzoic acid

+ triketone

triclopyr

+ dicamba

+ mesotrione

POST

Sublime

4

POST

27

POST

Groups 5 + 14

14

Triazolinone

+ triazinone

sulfentrazone

+ metribuzin

PRE/POST

Sulfencore

5

POST

Groups 8 + 14

8

Phosphorodithioate

+ oxadiazole

bensulide

+ oxadiazon

PRE

Goosegrass/Crabgrass Control

14

PRE

 

Publication #SS-AGR-394

Release Date:March 2nd, 2023

Related Experts

Unruh, Joseph Bryan

Specialist/SSA/RSA

University of Florida

Leon, Ramon

external

University of Florida

Petelewicz, Pawel

Specialist/SSA/RSA

University of Florida

  • Critical Issue: Agricultural and Food Systems
Management
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About this Publication

This document is SS-AGR-394, one of a series of the Agronomy Department, UF/IFAS Extension. Original publication date August 2015. Revised February 2023. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this publication.

About the Authors

Pawel Petelewicz, assistant professor, Agronomy Department; J. Bryan Unruh, professor and associate center Director, Environmental Horticulture Department, UF/IFAS West Florida Research and Education Center; and Ramon G. Leon, professor, courtesy faculty, Agronomy Department, North Carolina State University, Department of Crop and Soil Sciences, Raleigh, NC; UF/IFAS Extension, Gainesville, FL 32611.

 

Contacts

  • Joseph Unruh
  • Pawel Petelewicz