control of protoporphyrinogen oxidase inhibitor–resistant common waterhemp (amaranthus rudis) in...

BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, researchlibraries, and research funders in the common goal of maximizing access to critical research.

Control of Protoporphyrinogen Oxidase Inhibitor–Resistant Common Waterhemp(Amaranthus rudis) in Corn and SoybeanAuthor(s): DOUGLAS E. SHOUP and KASSIM AL-KHATIBSource: Weed Technology, 18(2):332-340. 2004.Published By: Weed Science Society of AmericaDOI: http://dx.doi.org/10.1614/WT-03-079R1URL: http://www.bioone.org/doi/full/10.1614/WT-03-079R1

BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, andenvironmental sciences. BioOne provides a sustainable online platform for over 170 journals and books publishedby nonprofit societies, associations, museums, institutions, and presses.

Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance ofBioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use.

Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiriesor rights and permissions requests should be directed to the individual publisher as copyright holder.

http://dx.doi.org/10.1614/WT-03-079R1

http://www.bioone.org/doi/full/10.1614/WT-03-079R1

http://www.bioone.org

http://www.bioone.org/page/terms_of_use

332

Weed Technology. 2004. Volume 18:332–340

Control of Protoporphyrinogen Oxidase Inhibitor–Resistant Common Waterhemp(Amaranthus rudis) in Corn and Soybean1

DOUGLAS E. SHOUP and KASSIM AL-KHATIB2

Abstract: Field experiments were conducted in 2001 and 2002 to evaluate the efficacy of herbicideson protoporphyrinogen oxidase (protox, EC 1.3.3.4) inhibitor–resistant common waterhemp in cornand soybean. All corn herbicides tested gave greater than 90% common waterhemp control by 8 wkafter postemergence herbicide treatment (WAPT). In soybean, common waterhemp control was lessthan 40% by 8 WAPT with postemergence protox-inhibiting herbicides lactofen and acifluorfen.However, preemergence protox-inhibiting herbicides sulfentrazone and flumioxazin gave greater than85% common waterhemp control in both years. The greatest common waterhemp control in soybeanwas with glyphosate alone, alachlor 1 metribuzin, alachlor followed by (fb) glyphosate, and S-metolachlor 1 metribuzin fb glyphosate.Nomenclature: Acifluorfen; alachlor; flumioxazin; glyphosate; lactofen; S-metolachlor; metribuzin;sulfentrazone; common waterhemp, Amaranthus rudis Sauer #3 AMATA; corn, Zea mays L. #ZEAMX ‘RRX740RR’; soybean, Glycine max (L.) Merr. ‘Asgrow 3701’.Additional index words: Acetochlor, ALS-resistance, atrazine, bromoxynil, carfentrazone, cloma-zone, clopyralid, dicamba, diflufenzopyr, dimethenamid-P, flumetsulam, glufosinate, halosulfuron-methyl, imazamox, imazaquin, imazethapyr, isoxaflutole, mesotrione, pendimethalin, primisulfuron-methyl, prosulfuron, protox-resistance, thifensulfuron-methyl.Abbreviations: ALS, acetolactate synthase; proto, protoporphyrin IX; protogen, protoporphyrinogenIX; protox, protoporphyrinogen oxidase; WAPT, weeks after postemergence herbicide treatment.

INTRODUCTION

Common waterhemp is a troublesome weed through-out the Midwest United States because of its prolific seedproduction and rapid growth characteristics (Battles etal. 1998; Bensch et al. 2003). Horak and Loughin (2000)found that common waterhemp is second to Palmer am-aranth (Amaranthus palmeri) in competitiveness amongthe Amaranthus spp. common in Kansas. Hager et al.(2002) showed that common waterhemp populations of200 plants/m2 decreased soybean yield by 43%. Benschet al. (2003) found that when common waterhemp wasallowed to emerge with soybean at densities of 8 plants/m of row, yield was reduced up to 56%.

Control of common waterhemp has been achievedwith several preemergence and postemergence herbi-cides. Corn herbicides that control common waterhemp

1 Received for publication March 18, 2003, and in revised form September30, 2003. Publication 03-287-5 Kansas State University Agricultural Experi-ment Station Journal Series.

2 Graduate Research Assistant and Professor, Department of Agronomy,Kansas State University, Manhattan, KS 66506. Corresponding author’sE-mail: [email protected].

3 Letters followed by this symbol are a WSSA-approved computer codefrom Composite List of Weeds, Revised 1989. Available only on computerdisk from WSSA, 810 East 10th Street, Lawrence, KS 66044-8897.

include triazines, chloroacetamides, growth regulators,acetolactate synthase (ALS, EC 2.2.1.6)–inhibiting her-bicides, isoxaflutole, and glyphosate in glyphosate-resis-tant corn (Anderson et al. 1996; Comfort et al. 2003;Regehr et al. 2003; Sprague and Hager 2003). Excellentcommon waterhemp control also has been achieved withmany soybean herbicides, such as dinitroanilines, chlo-roacetamides, metribuzin, protoporphyrinogen oxidase(protox, EC 1.3.3.4)–inhibiting herbicides, ALS-inhibit-ing herbicides, and glyphosate in glyphosate-resistantsoybean (Mayo et al. 1995; Regehr et al. 2003; Sweatet al. 1998).

Common waterhemp has developed resistance to threedifferent herbicide modes of action including photosys-tem II–inhibiting herbicides (Anderson et al. 1996),ALS-inhibiting herbicides (Horak and Peterson 1995),and, most recently, protox-inhibiting herbicides (Shoupet al. 2003). Triazine-resistant waterhemp was first con-firmed in 1990 in Nebraska (Anderson et al. 1996). Themechanism of resistance to triazine herbicides is an ami-no acid change in the D1 protein in the thylakoid mem-branes, the active site of triazine herbicides (Gronwald1997). However, a triazine-resistant biotype of common

WEED TECHNOLOGY

Volume 18, Issue 2 (April–June) 2004 333

waterhemp recently found in Illinois showed an alternatemechanism of resistance (Tranel and Patzoldt 2002).ALS resistance in common waterhemp was first reportedin Kansas in 1993 (Horak and Peterson 1995). The com-mon mechanism of resistance to ALS-inhibiting herbi-cides is a single amino acid change at one of severalpositions in the ALS enzyme (Guttieri et al. 1996; Her-vieu and Vaucheret 1996; Tranel and Wright 2002;Woodworth et al. 1996; Yadav et al. 1986). Protox re-sistance in common waterhemp was first discovered in2000 in Northeast Kansas. However, the mechanism ofresistance to protox-inhibiting herbicides is not known(Shoup et al. 2003). Resistance to three herbicide modesof action confirms the genetic variability in the commonwaterhemp species.

Protox is a membrane-bound enzyme that convertsprotoporphyrinogen IX (protogen) to protoporphyrin IX(proto), which is eventually synthesized to heme or chlo-rophyll (Beale and Weistein 1990; Matringe et al. 1992).Protox-inhibiting herbicides block the protox enzyme,resulting in a buildup of protogen in the plastid (Becerriland Duke 1989; Jacobs et al. 1991; Lee et al. 1993;Lehnen et al. 1990). The excess protogen eventuallyleaks from the plastid into the cytoplasm, where it isconverted to proto (J. M. Jacobs and N. J. Jacobs 1993;Lee et al. 1993). Once proto is exposed to light andoxygen; toxic oxygen species are ultimately producedresulting in cell membrane destruction (Duke et al.1991).

Protox-inhibiting herbicides provide effective controlof common waterhemp and other broadleaf weeds (Re-gehr et al. 2003; Sweat et al. 1998). Although the de-velopment of glyphosate-resistant crops has decreasedthe use of protox-inhibiting herbicides in soybean overthe past few years, protox-inhibiting herbicides are theonly postemergence herbicide option for farmers to con-trol ALS inhibitor–resistant common waterhemp in con-ventional soybean.

In 2000, a common waterhemp biotype was confirmedto be resistant to protox-inhibiting herbicides (Shoup etal. 2003). The resistant biotype was 82, 34, 8, and 4times more tolerant than a susceptible biotype to post-emergence applications of lactofen, acifluorfen, fome-safen, and sulfentrazone, respectively. In addition, theresistant biotype also was resistant to ALS-inhibitingherbicides. The objective of this research was to studythe efficacy of several corn and soybean herbicides onthe common waterhemp biotype resistant to protox- andALS-inhibiting herbicides.

MATERIALS AND METHODS

General. Field experiments were conducted in 2001 and2002 near Sabetha in Northeast Kansas in the same fieldwhere the resistant biotype was found. The field hadbeen planted with soybean for the past 15 yr and hadbeen treated with acifluorfen for the past 4 yr. The com-mon waterhemp population in the field consisted ofgreater than 80% protox inhibitor–resistant plants andwas consistent throughout the field, reaching populationsas high as 1,255 plants/m2 (data not shown). The soilwas a Judson silt loam (fine-silty, mixed, superactive,mesic Cumulic Hapludolls) with an organic matter con-tent of 2.5% in both years and soil pH of 7.1 and 6.8for corn and 7.0 and 6.8 for soybean in 2001 and 2002,respectively. Herbicides were selected based on theirweed control spectrum, and appropriate adjuvants wereadded according to the label recommendations. All treat-ments were applied using a CO2-pressurized bicycle-typesprayer with flat-fan nozzles4 calibrated to deliver 187L/ha at 138 kPa.

Experiments were conducted as randomized completeblock designs. Treatments were replicated four times.Data were tested for homogeneity of variance by plottingresiduals. A log transformation was performed beforeanalysis and improved visual ratings for corn only. Corndata were transformed and analyzed using analysis ofvariance, and means were separated using LSD at P 50.05. Untransformed means are presented for corn, withdifferences representing the transformed means. Soybeandata were analyzed using analysis of variance of untrans-formed means separated using LSD at P 5 0.05.

Corn. ‘RRX740RR’ glyphosate-resistant corn was plant-ed at a seeding rate of 51,900 seeds/ha in 2001 and 2002.Corn plots were 7.6 m long and four rows wide, andcorn was planted 76 cm apart. Corn was planted on April20 and April 17 in 2001 and 2002, respectively.

There were 14 corn herbicide treatments in 2001 and2002 (Tables 1 and 2). Preemergence herbicides wereapplied on April 21 and April 22 in 2001 and 2002,respectively. Postemergence herbicides were applied onMay 14 and May 21 in 2001 and 2002, respectively.Postemergence herbicides were applied when weedswere 8 to 10 cm tall. Weed populations in corn plotsconsisted of common waterhemp, giant foxtail (Setariafaberi Herrm.), yellow foxtail [Setaria glauca (L.)Beauv], common lambsquarters (Chenopodium albumL.), common cocklebur (Xanthium strumarium L.), and

4 TeeJet XR 8002, Spraying Systems Co., North Avenue, Wheaton, IL60188.

SHOUP AND AL-KHATIB: PROTOX INHIBITOR–RESISTANT COMMON WATERHEMP CONTROL

334 Volume 18, Issue 2 (April–June) 2004

Tab

le1.

Gen

eral

wee

dco

ntro

lan

dco

mm

onw

ater

hem

pco

ntro

l2,

4,an

d8

WA

PTas

affe

cted

byhe

rbic

ides

appl

ied

onco

rnin

2001

.a,b

Her

bici

detr

eatm

ent

Rat

eA

pplic

atio

ntim

ing

Gen

eral

wee

dco

ntro

lc

2W

APT

4W

APT

8W

APT

Com

mon

wat

erhe

mp

cont

rold

2W

APT

4W

APT

8W

APT

g/ha

%

Dim

ethe

nam

id-P

fbdi

cam

ba1

atra

zine

947

fb54

01

1,03

1PR

Efb

POST

97a

97a

98a

99ab

100

a99

abD

imet

hena

mid

-P1

atra

zine

fbdi

flufe

nzop

yr1

dica

mba

953

11,

851

fb60

115

4PR

Efb

POST

98a

87a

91a

100

a98

ab97

abD

imet

hena

mid

-Pfb

diflu

fenz

opyr

1di

cam

ba94

71

901

231

PRE

fbPO

ST97

a99

a99

a10

0a

99ab

100

abA

ceto

chlo

rfb

glyp

hosa

te1

atra

zine

58fb

1,12

21

1,12

2PR

Efb

POST

99a

90a

88a

100

a98

ab96

abA

ceto

chlo

r1

atra

zine

fbgl

ypho

sate

1,89

31

940

fb84

1PR

Efb

POST

99a

99a

98a

100

a10

0ab

99ab

Ace

toch

lor

fbdi

cam

ba1

halo

sulf

uron

-met

hyl

3,92

6fb

280

135

PRE

fbPO

ST97

a91

a90

a98

ab98

ab97

abS-

Met

olac

hlor

1at

razi

nefb

prim

isul

furo

n-m

ethy

l1

dica

mba

1,49

41

1,19

8fb

261

154

PRE

fbPO

ST95

a95

a96

a10

0a

98ab

99ab

S-M

etol

achl

or1

atra

zine

fbpr

osul

furo

n1

prim

isul

furo

n-m

ethy

l1,

494

11,

198

fb20

120

PRE

fbPO

ST99

a10

0a

98a

100

a10

0a

99ab

Mes

otri

one

1S-

met

olac

hlor

210

170

7PR

E96

a93

a91

a10

0a

97bc

96ab

S-M

etol

achl

orfb

mes

otri

one

1at

razi

ne70

7fb

105

156

1PR

Efb

POST

96a

90a

92a

98b

93c

94b

S-M

etol

achl

orfb

carf

entr

azon

e-et

hyl

1flu

met

sula

m1

clop

yral

id1,

339

fb9

165

117

5PR

Efb

POST

97a

92a

91a

99ab

97ab

c95

bS-

Met

olac

hlor

1at

razi

nefb

brom

oxyn

il1

atra

zine

1,41

31

1,82

6fb

280

156

1PR

Efb

POST

97a

88a

93a

100

a98

ab98

abS-

Met

olac

hlor

1at

razi

ne1

isox

aflut

ole

1,16

71

936

170

PRE

99a

100

a10

0a

100

a10

0a

100

aIs

oxafl

utol

efb

brom

oxyn

il1

atra

zine

70fb

280

156

1PR

Efb

POST

100

a10

0a

100

a10

0a

100

a10

0ab

aA

bbre

viat

ions

:fb

,fo

llow

edby

;PR

E,

pree

mer

genc

e;PO

ST,

post

emer

genc

e;W

APT

,w

eeks

afte

rpo

stem

erge

nce

herb

icid

etr

eatm

ent.

bM

eans

with

ina

colu

mn

follo

wed

byth

esa

me

lette

rar

eno

tsi

gnifi

cant

base

don

LSD

atP

50.

05.

cW

eed

spec

ies

incl

uded

com

mon

cock

lebu

r,co

mm

onla

mbs

quar

ters

,co

mm

onsu

nflow

er,

com

mon

wat

erhe

mp,

gian

tfo

xtai

l,an

dye

llow

foxt

ail.

dG

reat

erth

an80

%of

the

com

mon

wat

erhe

mp

popu

latio

nw

asre

sist

ant

topr

otop

orph

yrin

ogen

oxid

ase–

inhi

bitin

ghe

rbic

ides

.

WEED TECHNOLOGY


Tab

le2.

Gen

eral

wee

dco

ntro

lan

dco

mm

onw

ater

hem

pco

ntro

l0,

2,4,

and

8W

APT

asaf

fect

edby

herb

icid

esap

plie

don

corn

in20

02.a,

b

Her

bici

detr

eatm

ent

Rat

eA

pplic

atio

ntim

ing

Gen

eral

wee

dco

ntro

lc

0W

APT

e2

WA

PT4

WA

PT8

WA

PT

Com

mon

wat

erhe

mp

cont

rold

0W

APT

2W

APT

4W

APT

8W

APT

g/ha

%

Dim

ethe

nam

id-P

fbdi

cam

ba1

atra

zine

947

fb54

01

1,03

1PR

Efb

POST

86f

86ab

82ab

c82

abcd

100

a10

0a

100

a10

0a

Dim

ethe

nam

id-P

1at

razi

nefb

diflu

fenz

opyr

1di

cam

ba95

31

1,85

1fb

601

154

PRE

fbPO

ST97

abc

97a

96ab

97ab

100

a10

0a

96ab

100

a

Dim

ethe

nam

id-P

fbdi

flufe

nzop

yr1

dica

mba

947

190

123

1PR

Efb

POST

91cd

ef91

a92

ab92

ab10

0a

100

a99

ab99

aA

ceto

chlo

rfb

glyp

hosa

te1

atra

zine

58fb

1,12

21

1,12

2PR

Efb

POST

90de

f96

a97

a98

a10

0a

100

a10

0a

99a

Ace

toch

lor

1at

razi

nefb

glyp

hosa

te1,

893

194

0fb

841

PRE

fbPO

ST95

abcd

e10

0a

99a

100

a10

0a

100

a10

0a

100

aA

ceto

chlo

rfb

dica

mba

1ha

losu

lfur

on-m

ethy

l3,

926

fb28

01

35PR

Efb

POST

95ab

cd96

a95

ab94

ab10

0a

100

a98

ab10

0a

S-M

etol

achl

or1

atra

zine

fbpr

imis

ulfu

ron-

met

h-yl

1di

cam

ba1,

494

11,

198

fb26

115

4PR

Efb

POST

97ab

c98

a97

a96

ab10

0a

100

a99

ab10

0a

S-M

etol

achl

or1

atra

zine

fbpr

osul

furo

n1

prim

isul

furo

n-m

ethy

l1,

494

11,

198

fb20

120

PRE

fbPO

ST94

abcd

e97

a92

ab88

abc

100

a10

0a

99ab

100

a

Mes

otri

one

1S-

met

olac

hlor

210

170

7PR

E93

bcde

81ab

72c

75cd

100

a10

0a

93b

99a

S-M

etol

achl

orfb

mes

otri

one

1at

razi

ne70

7fb

105

156

1PR

Efb

POST

93bc

de72

b76

c73

d93

b98

a96

ab99

aS-

Met

olac

hlor

fbca

rfen

traz

one-

ethy

l1

flum

et-

sula

m1

clop

yral

id1,

339

fb9

165

117

5PR

Efb

POST

89ef

72b

79bc

79bc

d98

a90

b95

ab98

a

S-M

etol

achl

or1

atra

zine

fbbr

omox

ynil

1at

ra-

zine

1,41

31

1,82

6fb

280

156

1PR

Efb

POST

100

a10

0a

99a

100

a10

0a

100

a10

0a

100

a

S-M

etol

achl

or1

atra

zine

1is

oxafl

utol

e1,

167

193

61

70PR

E10

0a

100

a98

a98

a10

0a

100

a99

a10

0a

Isox

aflut

ole

fbbr

omox

ynil

1at

razi

ne70

fb28

01

561

PRE

fbPO

ST96

abc

97a

97a

97ab

100

a10

0a

99a

99a

aA

bbre

viat

ions

:fb

,fo

llow

edby

;PR

E,

pree

mer

genc

e;PO

ST,

post

emer

genc

e;W

APT

,w

eeks

afte

rpo

stem

erge

nce

herb

icid

etr

eatm

ent.

bM

eans

with

ina

colu

mn

follo

wed

byth

esa

me

lette

rar

eno

tsi

gnifi

cant

base

don

LSD

atP

50.

05.

cW

eed

spec

ies

incl

uded

com

mon

cock

lebu

r,co

mm

onla

mbs

quar

ters

,co

mm

onsu

nflow

er,

com

mon

wat

erhe

mp,

gian

tfo

xtai

l,an

dye

llow

foxt

ail.

dG

reat

erth

an80

%of

the

com

mon

wat

erhe

mp

popu

latio

nw

asre

sist

ant

topr

otop

orph

yrin

ogen

oxid

ase–

inhi

bitin

ghe

rbic

ides

.e

0W

APT

5ra

tings

befo

repo

stem

erge

nce

herb

icid

esw

ere

appl

ied.



common sunflower (Helianthus annuus L.). Corn injury,general weed control, and common waterhemp controlratings were determined 2, 4, and 8 wk after postemer-gence herbicide treatment (WAPT) in 2001 and 0, 2, 4,and 8 WAPT in 2002. Visual ratings were based on 0 5no crop injury or weed control and 100 5 mortality.Corn was harvested by hand from the middle 4.6 m2 ineach plot. Grain was weighed and adjusted to 15.5%moisture.5

Soybean. ‘Asgrow 3701’, glyphosate-resistant soybean,was planted on May 1 and May 10 in 2001 and 2002,respectively, at a seeding rate of 296,000 seeds/ha. Soy-bean plots were 3 m wide and 7.6 m long, and soybeanrows were 20 cm apart.

There were 17 soybean herbicide treatments in 2001and 2002 (Table 3). Preemergence herbicides were ap-plied on May 2 and May 15 in 2001 and 2002, respec-tively, whereas postemergence herbicides were appliedon May 24 and June 5 in 2001 and 2002, respectively.The second glyphosate treatment was applied on June 18and June 21 in 2001 and 2002, respectively. Postemer-gence herbicides were applied when common waterhempwas 8 to 10 cm tall. Weed populations for both yearswere mainly common waterhemp; thus, only commonwaterhemp control and soybean injury ratings were de-termined at 0, 2, 4, and 8 WAPT. Visual control ratingswere determined as described previously.

Common waterhemp height, population, and dryweight were determined 8 and 5 WAPT in 2001 and2002, respectively. Height of three common waterhempplants in each plot was determined. Common waterhempplants were counted, and aboveground biomass was har-vested from a 0.28-m2 area in the middle of each plot;then plant numbers were adjusted to plants per squaremeter. Plants were dried at 70 C for 72 h and weighed.

RESULTS AND DISCUSSION

Corn Study. At 2 WAPT, corn injury was less than 5%for all herbicides except mesotrione, where injury was15% (data not shown). Mesotrione injury symptomswere slight bleaching, but plants completely recoveredby 4 WAPT.

There were significant year by treatment interactions;thus, common waterhemp control and general weed con-trol are presented by year. In 2001, no weed control rat-ings were taken before postemergence herbicide appli-cation. Isoxaflutole followed by (fb) bromoxynil 1 at-

5 GAC 2100 Grain Analysis Computer, Dickey-John Corp., P.O. Box 10,Auburn, IL 62615.

razine gave 100% general weed control throughout thegrowing season (Table 1). All other treatments gavegreater than 85% general weed control throughout thegrowing season. Common waterhemp control was great-er than 95% with all herbicide treatments throughout thegrowing season except with S-metolachlor fb mesotrione1 atrazine, where common waterhemp control was 93and 94% at 4 and 8 WAPT, respectively (Table 1).

In 2002, all preemergence herbicides gave greater than85% general weed control by 0 WAPT (Table 2). At 2WAPT, general weed control was greater than 85% withall herbicide treatments except mesotrione 1 S-meto-lachlor, S-metolachlor fb mesotrione 1 atrazine, and S-metolachlor fb carfentrazone-ethyl 1 flumetsulam 1clopyralid. General weed control with these three her-bicide treatments ranged between 81 and 72% and con-tinued at this level of control throughout the growingseason. Yellow foxtail was not controlled with mesotri-one 1 S-metolachlor or S-metolachlor fb mesotrione 1atrazine. Decreased control with these herbicide treat-ments is likely from a combination of a low rate of me-tolachlor and a lack of significant rainfall until 5 d aftertreatment. Common lambsquarters was not controlledwith S-metolachlor fb carfentrazone-ethyl 1 flumetsu-lam 1 clopyralid. At 4 and 8 WAPT, dimethenamid-Pfb dicamba 1 atrazine gave less than 85% general weedcontrol. The reduction in weed control with dimethen-amid-P fb dicamba 1 atrazine was mainly due to a re-duction in yellow foxtail control. Dimethenamid has ahalf-life of 5 to 6 wk in soil and may explain the de-crease in yellow foxtail control as the season progressed(WSSA 2002). All other herbicides continued to providegreater than 85% general weed control throughout thegrowing season.

In 2002, all herbicide treatments gave greater than95% common waterhemp control throughout the grow-ing season except S-metolachlor fb mesotrione 1 atra-zine at 0 WAPT, S-metolachlor fb carfentrazone-ethyl 1flumetsulam 1 clopyralid at 2 WAPT, and mesotrione 1S-metolachlor at 4 WAPT, where common waterhempcontrol with these treatments were 93, 90, and 93%, re-spectively. However, by 8 WAPT all herbicide treat-ments gave near perfect control of common waterhemp.

In 2001, yields were higher in all herbicide treatmentscompared with the nontreated check (data not shown).The highest yielding treatments were acetochlor 1 at-razine fb glyphosate and isoxaflutole fb bromoxynil 1atrazine, which yielded 4,434 and 4,433 kg/ha, respec-tively. Corn yields were similar among other herbicidetreatments. In 2002, corn yields were not considered be-cause of severe lodging at the end of the growing season.

WEED TECHNOLOGY


Tab

le3.

Com

mon

wat

erhe

mp

cont

rol

0,2,

4,an

d8

WA

PTas

affe

cted

byhe

rbic

ides

appl

ied

onso

ybea

nin

2001

and

2002

.a,b

Her

bici

detr

eatm

ent

Rat

eA

pplic

atio

ntim

ing

Com

mon

wat

erhe

mp

cont

rolc

2001

0W

APT

d2

WA

PT4

WA

PT8

WA

PT

2002

0W

APT

2W

APT

4W

APT

8W

APT

g/ha

%

Lac

tofe

nA

ciflu

orfe

nL

acto

fen

1th

ifen

sulf

uron

Sulf

entr

azon

efb

glyp

hosa

teFl

umio

xazi

nfb

glyp

hosa

teC

lom

azon

e1

sulf

entr

azon

e

219

420

219

12

210

fb1,

122

89fb

1,12

284

142

1

POST

POST

POST

PRE

fbPO

STPR

Efb

POST

PRE

0 0 0 97ab

96ab

100

a

51e

15f

55e

100

a99

a96

ab

41e

15f

34e

99ab

98ab

c94

abc

35d

9e

33d

99a

94a

86ab

0 0 0 88c

95b

76d

44c

41c

44c

100

a10

0a

78b

19e

35cd

30d

100

a10

0a

39c

13d

19d

11d

99a

100

a43

cPe

ndim

etha

linfb

imaz

amox

1ac

ifluo

rfen

Pend

imet

halin

1im

azaq

uin

fbac

ifluo

rfen

Pend

imet

halin

1im

azaq

uin

1su

lfen

traz

one

Pend

imet

halin

1im

azaq

uin

1flu

mio

xazi

nPe

ndim

etha

linfb

imaz

etha

pyr

1gl

ypho

sate

Gly

phos

ate

1,15

7fb

351

210

841

113

91

210

841

113

91

210

841

113

91

891,

157

fb72

184

11,

122

PRE

fbPO

STPR

Efb

POST

PRE

PRE

PRE

fbPO

STPO

ST

81c

84c

94b

98ab

84c

0

69d

76d

84c

95ab

89bc

89bc

76d

78d

78d

90bc

89c

92ab

c

41d

35d

30d

71c

79bc

90ab

96ab

97ab

98ab

96ab

96ab

0

97a

98a

97a

93a

99a

99a

97ab

96ab

97ab

92b

100

a10

0a

94ab

94ab

95ab

90b

100

a99

abG

lyph

osat

efb

glyp

hosa

teA

lach

lor

fbgl

ypho

sate

Ala

chlo

r1

met

ribu

zin

S-M

etol

achl

or1

met

ribu

zin

fbgl

ypho

sate

S-M

etol

achl

or1

met

ribu

zin

fbth

ifen

sulf

uron

1,12

21

1,12

22,

805

fb1,

122

2,80

51

421

1,32

51

316

fb1,

122

1,54

61

368

fb2

POST

fbPO

STPR

Efb

POST

PRE

PRE

fbPO

STPR

Efb

POST

010

0a

100

a99

ab10

0a

89bc

100

a10

0a

100

a10

0a

100

a10

0a

99ab

100

a10

0a

100

a98

a97

a99

a99

a

010

0a

100

a10

0a

100

a

99a

100

a99

a10

0a

100

a

100

a10

0a

100

a10

0a

100

a

100

a10

0a

100

a10

0a

100

a

aA

bbre

viat

ions

:fb

,fo

llow

edby

;PR

E,

pree

mer

genc

e;PO

ST,

post

emer

genc

e;W

APT

,w

eeks

afte

rpo

stem

erge

nce

herb

icid

etr

eatm

ent.

bM

eans

with

ina

colu

mn

follo

wed

byth

esa

me

lette

rar

eno

tsi

gnifi

cant

base

don

LSD

atP

50.

05.

cG

reat

erth

an80

%of

the

com

mon

wat

erhe

mp

popu

latio

nw

asre

sist

ant

topr

otop

orph

yrin

ogen

oxid

ase–

inhi

bitin

ghe

rbic

ides

.d

0W

APT

5ra

tings

befo

repo

stem

erge

nce

herb

icid

esw

ere

appl

ied.



Soybean Study. Soybean visible injury ratings for aci-fluorfen and lactofen ranged between 12 and 15%; how-ever, soybean plants totally recovered from herbicide in-jury within 2 WAPT (data not shown). Acifluorfen andlactofen injury symptoms were slight chlorotic and ne-crotic spots. Soybean plants were not injured by any oth-er herbicide treatment.

In 2001, postemergence applications of protox-inhib-iting herbicides lactofen or acifluorfen caused stunting,chlorosis, necrosis, and leaf crinkling to the resistant bio-type of common waterhemp; however, plants recoveredby 4 WAPT. Common waterhemp control was greaterwith lactofen compared with acifluorfen, but control witheither herbicide was less than 40% at 8 WAPT (Table3). Higher resistance to acifluorfen may be due to theprevious selection pressure from acifluorfen, as reportedwith other cases of herbicide resistance (Baumgartner etal. 1999; Friesen et al. 1993; Shoup et al. 2003). Com-mon waterhemp control was not improved when thifen-sulfuron was added to lactofen, which is not surprisingbecause the resistant biotype also is resistant to ALS-inhibiting herbicides (Shoup et al. 2003). Preemergenceapplications of protox-inhibiting herbicides sulfentra-zone and flumioxazin gave 97 and 96% common water-hemp control, respectively. This was surprising becausethe resistant biotype was four times more resistant thana susceptible biotype to postemergence application ofsulfentrazone (Shoup et al. 2003). However, similar re-sults have been observed with other herbicide-resistantweed species. Research showed that triazine-resistantcommon waterhemp was susceptible to preemergenceapplications of triazine but not to postemergence appli-cations (Tranel and Patzoldt 2002). In addition, greaterR/S ratios for paraquat resistance were observed in moremature horseweed (Conyza canadensis) compared withseedling stages (Amsellem et al. 1993).

In general, sulfentrazone fb glyphosate, flumioxazin fbglyphosate, glyphosate fb glyphosate, alachlor fb gly-phosate, alachlor 1 metribuzin, S-metolachlor 1 metri-buzin fb glyphosate, and S-metolachlor 1 metribuzin fbthifensulfuron gave near perfect common waterhempcontrol throughout the 2001 growing season (Table 3).At 2 WAPT, pendimethalin fb imazamox 1 acifluorfen,pendimethalin 1 imazaquin fb acifluorfen, and pendi-methalin 1 imazaquin 1 sulfentrazone gave less than85% common waterhemp control, and common water-hemp control with these treatments continued to declinethroughout the growing season. At 8 WAPT, commonwaterhemp control with pendimethalin 1 imazaquin 1flumioxazin and pendimethalin fb imazethapyr 1 gly-phosate was less than 85%.

In 2002, postemergence treatments of lactofen, aci-fluorfen, and lactofen 1 thifensulfuron gave less than20% common waterhemp control by 8 WAPT (Table 3).Control with preemergence protox-inhibiting herbicidessulfentrazone and flumioxazin was greater than 85% at0 WAPT, but control was lower in 2002 compared with2001. All other herbicides gave greater than 85% com-mon waterhemp control throughout the growing season,except clomazone 1 sulfentrazone. In general, highercommon waterhemp control in 2002 compared with2001 can be explained by the higher moisture conditionsin 2002 (Coetzer et al. 2001; Kansas State University2003; Olson et al. 2000).

Common waterhemp heights were affected by herbi-cide treatments. In general, common waterhemp plantswere taller in plots treated with preemergence herbicidesclomazone 1 sulfentrazone, pendimethalin, pendime-thalin 1 imazaquin, pendimethalin 1 imazaquin 1 sul-fentrazone, and pendimethalin 1 imazaquin 1 flumiox-azin compared with the nontreated check (Table 4).Plants that survived preemergence herbicides were tallerthan the nontreated check plants because of less com-petition due to lower common waterhemp populations.All herbicide treatments reduced common waterhemppopulations. The least common waterhemp reductionswere with postemergence protox-inhibiting herbicidesacifluorfen and lactofen (Table 4). Glyphosate fb gly-phosate and alachlor fb glyphosate were the only her-bicide treatments to decrease common waterhemp pop-ulations by 100% in both years. Common waterhempdry weight response to herbicide treatments showed sim-ilar patterns to plant height response (Table 4).

This study illustrated that in spite of a high level ofresistance to postemergence applications of protox-inhib-iting herbicides acifluorfen and lactofen, the resistantbiotype was not resistant to preemergence protox-inhib-iting herbicides sulfentrazone and flumioxazin. In addi-tion, this study showed that all herbicide treatments gavenear perfect control of the resistant biotype in corn. Insoybean, sulfentrazone fb glyphosate, flumioxazin fbglyphosate, glyphosate fb glyphosate, alachlor fb gly-phosate, alachlor 1 metribuzin, S-metolachlor 1 metri-buzin fb glyphosate, and S-metolachlor 1 metribuzin fbthifensulfuron gave near-perfect control of the resistantbiotype. However, the only postemergence soybean her-bicide that controlled the resistant biotype was glyphos-ate, which is not an option in conventional soybean.Consequently, crop rotation to corn would be helpful touse the many corn herbicides that control the resistantbiotype. Crop rotation, herbicide rotation, and herbicide

WEED TECHNOLOGY


Tab

le4.

Com

mon

wat

erhe

mp

heig

hts,

dry

wei

ghts

,an

dpo

pula

tions

asaf

fect

edby

herb

icid

esap

plie

don

soyb

ean

in20

01an

d20

02.a,

b

Her

bici

detr

eatm

ent

Rat

eA

pplic

atio

ntim

ing

2001

c

Hei

ght

Popu

latio

ndW

eigh

t

2002

Hei

ght

Popu

latio

nW

eigh

t

g/ha

cmno

./m2

g/pl

ant

cmno

./m2

g/pl

ant

Lac

tofe

nA

ciflu

orfe

nL

acto

fen

1th

ifen

sulf

uron

Sulf

entr

azon

efb

glyp

hosa

teFl

umio

xazi

nfb

glyp

hosa

teC

lom

azon

e1

sulf

entr

azon

e

219

420

219

12

210

fb1,

122

89fb

1,12

284

142

1

POST

POST

POST

PRE

fbPO

STPR

Efb

POST

PRE

113

de11

0de

117

de51

ghi

108

def

148

abcd

230

b64

6a

213

b1

d5

d9

d

1.16

d0.

7d

1.82

d4.

05cd

3.07

cd8.

99bc

105

ab88

bc95

abc

0e

0e

126

a

116

b19

3a

144

b0

d0

d67

c

5.64

bc2.

38cd

3.09

cd0.

00d

0.00

d10

.82

abPe

ndim

etha

linfb

imaz

amox

1ac

ifluo

rfen

Pend

imet

halin

1im

azaq

uin

fbac

ifluo

rfen

Pend

imet

halin

1im

azaq

uin

1su

lfen

traz

one

Pend

imet

halin

1im

azaq

uin

1flu

mio

xazi

nPe

ndim

etha

linfb

imaz

etha

pyr

1gl

ypho

sate

Gly

phos

ate

1,15

7fb

351

210

841

113

91

210

841

113

91

210

841

113

91

891,

157

fb72

184

11,

122

PRE

fbPO

STPR

Efb

POST

PRE

PRE

PRE

fbPO

STPO

ST

166

abc

175

ab19

9a

171

ab14

4bc

d11

7cd

e

131

bc59

cd84

cd16

cd30

cd11

6bc

d

3.27

cd5.

26cd

11.8

2b

21.3

1a

3.82

cd3.

08cd

79bc

62cd

75bc

96ab

0e

30de

6d

7d

7d

17d

0d

2d

2.86

cd4.

53cd

11.6

2a

15.7

7a

0.00

d0.

23cd

Gly

phos

ate

fbgl

ypho

sate

Ala

chlo

rfb

glyp

hosa

teA

lach

lor

1m

etri

buzi

nS-

Met

olac

hlor

1m

etri

buzi

nfb

glyp

hosa

teS-

Met

olac

hlor

1m

etri

buzi

nfb

thif

ensu

lfur

on

1,12

21

1,12

22,

805

fb1,

122

2,80

51

421

1,32

51

316

fb1,

122

1,54

61

368

fb2

POST

fbPO

STPR

Efb

POST

PRE

PRE

fbPO

STPR

Efb

POST

0i

0i

97de

fg57

fgh

22hi

0d

0d

1d

1d

1d

0d

0d

1.23

d0.

73d

0.53

d

0e

0e

0e

0e

0e

0d

0d

0d

0d

0d

0.00

d0.

00d

0.00

d0.

00d

0.00

d

aA

bbre

viat

ions

:fb

,fo

llow

edby

;PR

E,

pree

mer

genc

e;PO

ST,

post

emer

genc

e.b

Mea

nsw

ithin

aco

lum

nfo

llow

edby

the

sam

ele

tter

are

not

sign

ifica

ntba

sed

onL

SDat

P5

0.05

.c

Har

vest

timin

gsw

ere

8an

d5

wk

afte

rpo

stem

erge

nce

herb

icid

etr

eatm

ent

in20

01an

d20

02,

resp

ectiv

ely.

dC

omm

onw

ater

hem

pw

ere

harv

este

din

a0.

28-m

2ar

eath

enad

just

edto

refle

ctpl

ants

per

squa

rem

eter

.



mixtures need to be implemented to decrease any furtherdevelopment of herbicide resistance (Valverde and Itoh2001).

ACKNOWLEDGMENTS

We thank Bayer, BASF, Syngenta, Dupont, Monsanto,and Valent for funding this research.

LITERATURE CITED

Amsellem, Z., M.A.K. Jansen, A.R.J. Driesenaar, and J. Gressel. 1993. De-velopmental variability of photooxidative stress tolerance in paraquat-resistant Conyza. Plant Physiol. 103:1097–1106.

Anderson, D. D., F. W. Roeth, and A. R. Martin. 1996. Occurrence and controlof triazine-resistant common waterhemp (Amaranthus rudis) in field corn(Zea mays). Weed Technol. 10:570–575.

Battles, B., B. Hartzler, and D. Buhler. 1998. Effect of common waterhempemergence date in soybean on growth and competitiveness. Proc. N.Cent. Weed Sci. Soc. 53:145–146.

Baumgartner, J. R., K. Al-Khatib, and R. S. Currie. 1999. Cross-resistance ofimazethapyr-resistant common sunflower (Helianthus annuus) to selectedimidazolinone, sulfonylurea, and triazolopyrimidine herbicides. WeedTechnol. 13:489–493.

Beale, S. I. and J. D. Weinstein. 1990. Tetrapyrrole metabolism in photosyn-thetic organisms. In H. A. Daily, ed. Biosynthesis of Heme and Chlo-rophylls. New York: McGraw-Hill. Pp. 287–391.

Becerril, J. M. and S. O. Duke. 1989. Protoporphyrin IX content correlateswith activity of photobleaching herbicides. Plant Physiol. 90:1175–1181.

Bensch, C. N., M. J. Horak, and D. E. Peterson. 2003. Interference of redrootpigweed (Amaranthus retroflexus), Palmer amaranth (A. palmeri), andcommon waterhemp (A. rudis) in soybean. Weed Sci. 51:37–43.

Coetzer, E., K. Al-Khatib, and T. M. Loughin. 2001. Glufosinate efficacy,absorption, and translocation in amaranth as affected by relative humidityand temperature. Weed Sci. 49:8–13.

Comfort, S. D., R. E. Gaussoin, B. F. Kappler, et al. 2003. Guide for WeedManagement in Nebraska. Lincoln, NE: University of Nebraska Coop-erative Extension EC02-130-D. Pp. 30–32.

Duke, S. O., J. Lydon, J. M. Becerril, T. D. Sherman, L. P. Lehnen, Jr., andH. Matsumoto. 1991. Protoporphyrinogen oxidase-inhibiting herbicides.Weed Sci. 39:465–473.

Friesen, L. F., I. N. Morrison, A. Rashid, and M. D. Devine. 1993. Responseof a chlorsulfuron-resistant biotype of Kochia scoparia to sulfonylureaand alternative herbicides. Weed Sci. 41:100–106.

Gronwald, J. W. 1997. Resistance to PS II inhibitor herbicides. In R. DePrado, J. Jorrı́n, and L. Garcı́a-Torres, eds. Weed and Crop Resistanceto Herbicides. Norwell, MA: Kluwer Academic. Pp. 53–59.

Guttieri, M. J., C. V. Eberlein, C. A. Mallory-Smith, and D. C. Thill. 1996.Molecular genetics of target-site resistance to acetolactate synthase in-hibiting herbicides. In T. M. Brown, ed. Molecular Genetics and Evo-lution of Pesticide Resistance. Washington, DC: American Chemical So-ciety. Pp. 10–16.

Hager, A. G., L. M. Wax, E. W. Stoller, and G. A. Bollero. 2002. Commonwaterhemp (Amaranthus rudis) interference in soybean. Weed Sci. 50:607–610.

Hervieu, F. and H. Vaucheret. 1996. A single amino acid change in acetolac-tate synthase confers resistance to valine in tobacco. Mol. Gen. Genet.251:220–224.

Horak, M. J. and T. M. Loughin. 2000. Growth analysis of four Amaranthusspecies. Weed Sci. 48:347–355.

Horak, M. J. and D. E. Peterson. 1995. Biotypes of Palmer amaranth (Ama-ranthus palmeri) and common waterhemp (Amaranthus rudis) are resis-tant to imazethapyr and thifensulfuron. Weed Technol. 9:192–195.

Jacobs, J. M. and N. J. Jacobs. 1993. Porphyrin accumulation and export byisolated barley (Hordeum vulgare) plastids. Plant Physiol. 101:1181–1187.

Jacobs, J. M., N. J. Jacobs, T. D. Sherman, and S. O. Duke. 1991. Effect ofdiphenyl ether herbicides on oxidation of protoporphyrinogen to proto-porphyrin in organella and plasma membrane enriched fractions of bar-ley. Plant Physiol. 97:197–203.

Kansas State University. 2003. Weather Data Library: Precipitation by Coun-ties: Web page: http://ftp.oznet.ksu.edu/wdl/drought/BR.PCP. Accessed:May 21, 2003.

Lee, H. J., M. V. Duke, and S. O. Duke. 1993. Cellular localization of pro-toporphyrinogen-oxidizing activities of etiolated barley (Hordeum vul-gare) leaves. Plant Physiol. 102:881–889.

Lehnen, L. P., T. D. Sherman, J. M. Becerril, and S. O. Duke. 1990. Tissueand cellular localization of acifluorfen-induced porphyrins in cucumbercotyledons. Pestic. Biochem. Physiol. 37:239–248.

Matringe, M., J. M. Camadro, M. A. Block, J. Joyard, R. Scalla, P. Labbe,and R. Douce. 1992. Localization within the chloroplast of protopor-phyrinogen oxidase the target enzyme for diphenyl ether-like herbicides.J. Biol. Chem. 267:4546–4651.

Mayo, M. M., M. J. Horak, D. E. Peterson, and J. E. Boyer. 1995. Differentialcontrol of four Amaranthus species by six postemergence herbicides insoybean (Glycine max). Weed Technol. 9:141–147.

Olson, B.L.S., K. Al-Khatib, P. Stahlman, and P. J. Isakson. 2000. Efficacyand metabolism of MON 37500 in Triticum aestivum and weedy grassspecies as affected by temperature and soil moisture. Weed Sci. 48:541–548.

Regehr, D. L., D. E. Peterson, P. D. Ohlenbusch, W. H. Fick, P. W. Stahlman,and R. E. Wolf. 2003. 2003 Chemical Weed Control for Field Crops,Pasture, Rangeland, and Noncropland. Report of Progress 902. Manhat-tan, KS: Kansas State University Agricultural Experiment Station andCooperative Extension Service. Pp. 20–21.

Shoup, D. E., K. Al-Khatib, and D. E. Peterson. 2003. Common waterhemp(Amaranthus rudis) resistance to protoporphyrinogen oxidase-inhibitingherbicides. Weed Sci. 51:145–150.

Sprague, C. L. and A. G. Hager. 2003. Weed control for corn, soybean, andsorghum. In Illinois Agricultural Pest Management Handbook. Urbana-Champaign, IL: University of Illinois Extension. Pp. 99–100.

Sweat, J. K., M. J. Horak, D. E. Peterson, R. W. Lloyd, and J. E. Boyer. 1998.Herbicide efficacy on four Amaranthus species in soybean (Glycine max).Weed Technol. 12:315–321.

Tranel, P. J. and W. L. Patzoldt. 2002. Atrazine resistance in waterhemp (Am-aranthus rudis and Amaranthus tuberculatus) that is not site of actionmediated. Weed Sci. Soc. Am. Abstr. 42:50.

Tranel, P. J. and T. R. Wright. 2002. Resistance of weeds to ALS-inhibitingherbicides: what have we learned? Weed Sci. 50:700–712.

Valverde, B. E. and K. Itoh. 2001. World rice and herbicide resistance. In S.B. Powles and D. L. Shaner, eds. Herbicide Resistance and World Grains.Boca Raton, FL: CRC. Pp. 195–249.

[WSSA] Weed Science Society of America. 2002. Herbicide Handbook. 8thed. Lawrence, KS: Weed Science Society of America. 493 p.

Woodworth, A. R., B. A. Rosen, and P. Bernasconi. 1996. Broad range resis-tance to herbicides targeting acetolactate synthase (ALS) in a field isolateof Amaranthus spp. is conferred by a trp to leu mutation in the ALSgene (accession no. U55852.) Plant Physiol. 111:1353.

Yadav, N., R. E. McDevitt, S. Benard, and S. C. Falco. 1986. Single aminoacid substitutions in the enzyme acetolactate synthase confer resistanceto the herbicide sulfometuron methyl. Proc. Natl. Acad. Sci. USA 83:4418–4422.

control of protoporphyrinogen oxidase inhibitor–resistant common waterhemp (amaranthus rudis) in...

Documents