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Publication #SS-AGR-244

Managing against the Development of Herbicide-Resistant Weeds: Sugarcane1

D. C. Odero, B. A. Sellers, J. A. Ferrell, and G. E. MacDonald2

Profitable sugarcane production in Florida requires effective weed management. Herbicides are a critical component of sugarcane weed management programs, because they provide an efficient and cost-effective means of weed control. However, excessive use of a single herbicide or group of herbicides with the same mechanism of action has resulted in the development of herbicide-resistant weeds. When herbicide-resistant weed populations appear, standard weed control treatments often become ineffective. As a result, alternative means of control must be used. In crops such as sugarcane where a limited number of herbicides are registered, the loss of a single effective herbicide can be very costly. Thus, it is critical to manage herbicides in order to prevent or delay the development of herbicide-resistant weed populations.

Growers and land managers must have a basic understanding of which herbicides have the same mechanism of action in order to successfully apply herbicides in a manner that reduces the likelihood of developing herbicide resistance. Table 1 lists herbicides by group number, mechanism of action, chemical family, common name, and trade name.

Figure 1. 

Sugarcane rows in the Everglades Agricultural Area (EAA) following herbicide application and cultivation.


Credit:

C. Odero, UF/IFAS


[Click thumbnail to enlarge.]

When planning a herbicide program to manage against herbicide resistance, you should avoid whenever possible the use of a single herbicide or herbicide group in consecutive years. However, Group 4 (2,4-D, dicamba), Group 5 (atrazine, ametryn, metribuzin), and Group 18 (asulam) herbicides are typically used in every year of a sugarcane crop because of the limited number of herbicides available and the perennial crop cycle of sugarcane. Worldwide, over 70 weed species have developed resistance to the triazine herbicides. These biotypes include several members of the genera Amaranthus, Ambrosia, Chenopodium, Eleusine, Panicum, and Solanum, which are commonly found in Florida sugarcane fields. Consequently, it is critical that other herbicide groups be utilized as part of an integrated weed control program to prevent the development of triazine-resistant weed populations. Although there are no reported cases of resistance to asulam, there is always a chance that resistant populations could develop. Until recently, asulam (Group 18) was the only herbicide that could be used for postemergence control of grass weeds in sugarcane. However, the registration of Envoke (Group 2) provides an alternate mechanism of action for postemergence grass weed control. For most grassy weeds, tank mixtures of asulam and Envoke are an effective resistance management strategy. Herbicide resistance is more likely to be a problem in fields successively planted to sugarcane. Rotational crops and fallow periods provide a valuable opportunity to control weeds using tillage, flooding, or herbicides with mechanism of action.

Although it is likely that small populations of herbicide-resistant weeds are already present in the Everglades Agricultural Area (EAA), herbicide resistance is currently not a significant problem. The continued use of integrated and properly managed weed control programs should ensure that resistance does not become a major issue in the future.

Tables

Table 1. 

Group number and mechanism of action of herbicides commonly used in sugarcane and crops grown in rotation with sugarcane.

Group number and mechanism of action1

Chemical family

Common name

Trade name(s)

Crop used in…

Group 1

Acetyl CoA carboxylase (ACCase)

inhibitors

aryloxyphenoxy-

propionates

fenoxaprop

Acclaim Extra

sod

fluazifop

Fusilade DX

fallow, canal banks

cyhalofop

Clincher

rice

quizalofop

Assure II

vegetables

cyclohexanediones

clethodim

Select, Selex Max

vegetables

sethoxydim

Poast, Poast plus

vegetables

Group 2

Acetolactate

synthase (ALS)

inhibitors

sulfonylureas

bensulfuron-methyl

Londax

rice

chlorsulfuron

Corsair

sod

halosulfuron-methyl

Sandea, Permit

sugarcane, rice

nicosulfuron

Accent

sweet corn

trifloxysulfuron-sodium

Envoke

sugarcane

pyrimidinylthiobenzoate

bispyribac-sodium

Regiment

rice

sulfonamide

penoxsulam

Grasp, Grasp Xtra2

rice

Group 3

Microtubule

assembly inhibitors

dinitroanilines

oryzalin

Surflan

sod

pendimethalin

Prowl 3.3, Prowl H2O, Pendimax 3.3

sugarcane

prodiamine

Barricade

sod

Group 4

Synthetic auxins

phenoxy acetic acids

2,4-D

several

sugarcane, rice, sweet corn

benzoic acid

dicamba

Banvel

sugarcane

pyridinecarboxylic acid

triclopyr

Grasp Xtra2

rice

Group 5

Photosystem II inhibitors

triazines

ametryn

Evik

sugarcane

atrazine

AAtrex, Atrazine (several), Bicep II Magnum3

sugarcane, sweet corn

hexazinone

K4 4

sugarcane

metribuzin

Sencor, Metribuzin 75

sugarcane

simazine

Princep, Simazine (several)

sweet corn

Group 6

Photosystem II

inhibitors (same mechanism

as group 5, but different

binding characteristics)

benzothiadiazinone

bentazon

Basagran

sweet corn, rice, vegetables

Group 7

Photosystem II

inhibitors (same mechanism as group

5 and 6, but different binding

characteristics)

Ureas

diuron

Diuron (several), Direx, Karmex, K44

sugarcane

linuron

Lorox

vegetables

Amide

propanil

Stam M4

rice

napropamide

Devrinol

vegetables

Group 8

Lipid synthesis inhibition

(not ACCase inhibition)

Thiocarbamates

     

EPTC

Eptam, Eradicane

sweet corn

thiobencarb

Bolero

rice

Phosphorodithioate

bensulide

Prefar

vegetables

Group 9

EPSP synthase

inhibitors

glycine

glyphosate

Roundup, Touchdown, others

fallow

Group 14

Protoporphyrinogen

oxidase (PPO) inhibitors

triazolinone

carfentrazone

Aim

sugarcane, rice, sweet corn

Diphenylethers

acifluorfen

Ultra Blazer

rice

oxyfluorfen

Goal

sweet corn

fomesafen

Reflex

snap beans

N-phenylphthalimides

flumioxazin

Valor SX

sugarcane

Oxadiazole

oxadiazon

Ronstar

sod

Group 15

unknown mechanism of action

Chloroacetamides

metolachlor

Dual Magnum, Pennant Magnum

sweet corn, sod

pronamide

Kerb

sod

Group 16

unknown mechanism of action

Benzofuran

ethofumesate

Prograss

sod

Group 18

DHP (dihydropteroate

synthase step) inhibitors

Carbamate

asulam

Asulam, (several) Asulox

sugarcane

Group 21

Cell wall synthesis

inhibitor (mechanism B)

Benzamide

isoxaben

Gallery

sod

Group 22

Photosystem I

electron diversion

Bipyridyliums

paraquat

Gramoxone

fallow

Group 27

Hydroxyphenyl-pyruvate-

dioxygenase inhibitors

Triketone

mesotrione

Callisto

sugarcane, sweet corn

1Group number and mechanism of action according to the Weed Science Society of America classification.

2Grasp Xtra is a commercial; blend of penoxsulam and triclopyr.

3Bicep II Magnum is a commercial blend of atrazine and metolachlor.

4K4 is a commercial blend of diuron and hexazinone.

Footnotes

1.

This document is SS-AGR-244, one of a series of the Agronomy Department, UF/IFAS Extension. Original publication date December 2005. Revised October 2014. This publication is also part of the Florida Sugarcane Handbook, an electronic publication of the Agronomy Department. For more information, contact the editor of the Sugarcane Handbook, Hardev Sandhu (hsandhu@ufl.edu).Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

D. C. Odero, assistant professor, Agronomy Department, UF/IFAS Everglades Research and Education Center, Belle Glade, FL; B. A. Sellers, associate professor, Agronomy Department, UF/IFAS Range Cattle Research and Education Center, Ona, FL; J. A. Ferrell, professor, Agronomy Department; G. E. MacDonald, professor, Agronomy Department; UF/IFAS Extension, Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition. Use herbicides safely. Read and follow directions on the manufacturer's label.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.