1

Chapter 8

DIVISION OF AGRICULTURER E S E A R C H & E X T E N S I O N

University of Arkansas System

Arkansas Grain Sorghum Production Handbook

Weed Control in Grain SorghumTom Barber, Bob Scott and Jason Norsworthy

Weed competition in grain sorghum reducesyields, causes harvesting losses and increasesseed content of the soil seedbank. Even lightweed infestations in the early growing seasonwill reduce yields significantly. Grain sorghumseedlings grow slowly and are weak competitorsto most weeds. Research data have shown

Figure 8-1. Weeds compete for light, moisture andnutrients.

that one pigweed plant per 3 feet of row left uncontrolled until sorghum reaches the 3-leafstage will reduce yields by 10%. Heavy infestationsof grassy weeds may cause up to a 20% yieldreduction in the first 2 weeks after sorghum germination. Late-season weed infestations haveless effect on produced yields but reduce harvest-ing efficiency and may reduce harvested yields.

Most grain sorghum is planted in early tomid-April throughout the state to allow floweringprior to a large buildup of sorghum midge.Although this early planting reduces insect pressure, it contributes additional stress to thegrain sorghum seedling. Grain sorghum was introduced from the warmer climates of Africaand grows best when soil and air temperatures riseabove 70°F. Seedlings stressed from cool and wetsoils are much more sensitive to weed competitionand herbicide injury.

The most troublesome weeds in Arkansasgrain sorghum include johnsongrass, broadleafsignalgrass, barnyardgrass, crabgrass, morning-glory, pigweed, prickly sida and sicklepod. Thereare fewer control options for weed control ingrain sorghum than in corn, cotton and soybeans.Grain sorghum lacks tolerance to many of thecommonly used grass and broadleaf herbicidesand is occasionally injured even by herbicideslabeled for use in sorghum. Unfavorable weatherconditions such as cool, wet soils, delayed cropemergence, deep planting, seedling diseases,poor soil physical conditions and poor qualityseed may contribute to seedling stress andherbicide injury.

Grain sorghum is almost always includedin a crop rotation schedule. Herbicides such as Pursuit, Reflex, Flexstar and other generic

UPDATED 4-2015

UPDATED 4-2015 2

fomesafen applied to soybeans the previous year

can remain in the soil and cause stand reductions

and/or injury to sorghum. ResolveQ, RealmQ

and AccentQ in corn and Staple applied to cotton

the previous year can also injure sorghum. In

addition, Newpath or Clearpath used in rice will

carry over to grain sorghum. Often the carryover

herbicide injury is not visible in very young

sorghum but becomes apparent at the 3- to 6-leaf

stage of growth. For carryover information on

common herbicides, refer to the Extension publi-

cation MP519, Row Crop Plant-Back Intervals for

Common Herbicides (available at www.uaex.edu).

A combination of tillage and chemical weed

control is usually most effective in grain sorghum.

Effective chemical weed control is dependent

upon proper weed identification and matching

herbicide rate and timing to the particular weeds.

Cool-season weeds should be destroyed prior to

planting to ensure that crop seedlings emerge

competition free. Most winter weeds may be

controlled with glyphosate, 2,4-D, dicamba

or paraquat. (For additional information, refer to

Extension publication MP44, Recommended Chemi-

cals for Weed and Brush Control, available from

county Extension offices throughout the state and

at www.uaex.edu.)

Broadleaf weeds may be controlled

postemergence, but there are few options for

postemergence grass control. Grassy weeds are

most effectively controlled with preemergence

herbicide applications. Johnsongrass (Sorghum

halepensea) and grain sorghum (Sorghum vulgare)

are genetically very similar, and there are no

approved herbicides that will selectively remove

johnsongrass from grain sorghum. Even light

infestations of johnsongrass in other crops

planted the previous year often turn into heavy

infestations in grain sorghum due to lack of

selective control. Fields with a history of johnson -

grass or bermudagrass should not be planted to

grain sorghum.

Herbicide programs for effective weed controlmust be developed based on weed spectrum andsoil type. Your county Extension agent receivesextensive training on weed identification andweed control technology and is available to assistin developing economical and effective controlprograms. MP44, Recommended Chemicals for Weedand Brush Control, is updated annually to reflectthe most current information on herbicide labelchanges and revised recommendations based onresearch data.

Herbicides Used forWeed Control

Effective weed control programs start withclean fields at planting. It is critical to removeexisting cool-season weeds with tillage or herbicides prior to planting. Glyphosate andglyphosate in combination with 2,4-D are veryeffective preplant herbicides.

Atrazine is the basis of most chemical weedcontrol programs in Arkansas grain sorghum. Itis estimated that greater than 90% of the acresplanted receive at least one application ofatrazine. In sites where weedy grasses are not aproblem, atrazine may be the only herbicideapplied. Although atrazine has some activity ongrassy weeds, it is considered a broadleaf herbi-cide. It may be combined with the chloroac-etamide herbicides such as Dual II Magnum,Outlook and Lasso to broaden the weed controlspectrum. Concep®-treated seed must be plantedif any of the chloroacetamides are to be used.These active ingredients are also sold in premixeswith atrazine under different names. Bicep IIMagnum and Guardsman Max are examples ofatrazine plus chloroacetamide premixes thatrequire Concep-treated seed.

Preemergence herbicides are applied afterthe sorghum has been planted and prior to emergence. The chloroacetamides such as Dual

UPDATED 4-2015 3

Magnum are taken into the weedy plants throughthe emerging coleoptiles and have little or noactivity on emerged weeds. These herbicides mustbe applied before targeted weeds germinate.Atrazine is effective as a preemergence or earlypostemergence herbicide. Dual Magnum, Lassoand Outlook primarily control grasses such ascrabgrass, barnyardgrass and broadleaf signalgrassbut also suppress yellow nutsedge and offer somecontrol of pigweeds. Combinations of these prod-ucts with atrazine as tank mixes or premixesapplied preemergence will control most seedlinggrasses and broadleaf weeds for 3 weeks.

Rainfall or irrigation is required to incorporatethe herbicides with the soil for activity. This isoften referred to as “activation” of the herbicide.However, large rains immediately after applicationmay move some of the herbicide into contactwith the germinating sorghum seedling and mayactually be taken into the germinating seed as itimbibes water. This usually results in delayedemergence and some crop injury. Under goodgrowing conditions, the symptoms are usuallyonly cosmetic and the sorghum resumes normalgrowth 7 to 10 days after emergence.

Applying high rates (2 pounds active ingredi-ent) of atrazine preemergence to sorghum is considered to be high risk. Significant stand lossesand delayed development of seedlings are com-mon following high rates of atrazine in cool, wetweather. Splitting the atrazine applications andapplying no more than 1 pound active ingredientat planting followed by an additional pound earlypostemergence has proven to be much safer tothe sorghum. Atrazine may also cause more injuryon sandy soils. To reduce injury, wait untilsorghum is up and growing well prior to atrazineapplication. In fields where grassy weeds areexpected to be a problem, a chloroacetamide preemergence alone or in combination with alow rate of atrazine followed by additionalatrazine early postemergence is a safe and veryeffective early-season weed control program.

Figure 8-2. Injury from high rates of Dual and atrazinecan occur under cool/wet conditions.

PostemergenceWeed Control

Control of weeds once they emerge in grain

sorghum can be difficult, especially with grass

species. There is currently no available option

for control of johnsongrass once it emerges in

grain sorghum fields. Other grasses such as

broadleaf signalgrass, crabgrass and barnyardgrass

can be controlled while they are small with

atrazine (AAtrex) and quinclorac (Facet L) applied

postemergence. Atrazine applied at rates higher

than 1 pound active ingredient per acre postemer-

gence may injure and/or kill sorghum in cool

conditions, especially on sandy soils or if it is not

actively growing. Other herbicides such as 2,4-D,

dicamba (Clarity), prosulfuron (Peak), bromoxynil

(Buctril) and Huskie are also effective postemer-

gence broadleaf herbicides for use in sorghum.

Paraquat (Gramoxone Max) is labeled for post-

directed use in larger grain sorghum to control

escaped weeds. Considerable crop leaf burn is

expected, and this option should be used only in

salvage situations where grassy weeds were not

controlled earlier in the season. (See label for

special precautions and injury warnings.)

UPDATED 4-2015 4

Standard Herbicide Program

General weed control strategy for grain

sorghum is as follows:

1. Plant Concep®-treated seed.

2. Dual Magnum 1-1.3 pt/A PRE, or Verdict

10 oz/A PRE, or Dual Magnum 1 pt/A + AAtrex

1.5-2 pt/A PRE.

3. V4 – Atrazine 2 pt/A + 1.3 pt/A Dual Magnum

POST for grass and broadleaf weeds

– Or include Facet L if high grass population.

– Can include Clarity or Huskie if high popu-

lations of pigweeds and morningglories.

4. Huskie can be applied for broadleaf weed

control up to 30-inch grain sorghum.

Figure 8-3. Bicep II Magnum 1.3 qt/A PRE followedby 1 qt/A AAtrex on 3-4 leaf sorghum.

Nutsedge Control in Sorghum

Yellow nutsedge and other annual sedges

are becoming an increasing problem in grain

sorghum. Permit herbicide can be applied for

nutsedge control from 2-leaf grain sorghum

through just prior to grain head emergence.

Application rates should not exceed 1 ounce per

acre when nutsedge is 4 to 12 inches tall. How-

ever, if nutsedge is allowed to reach 4 to 12 inches

tall, severe crop competition has already occurred.

Only one application of Permit can be made in

season to grain sorghum.

Harvest Aids

The absence of approved herbicides for

late-season weed control in grain sorghum often

permits escaped weeds to hinder harvesting opera-

tions. Roundup, Aim and sodium chlorate are

effective harvest aids that will desiccate weeds and

improve harvesting efficiency. Roundup provides

the best harvest aid to increase efficiency; Aim

should be added to desiccate vines. These should

be applied 7 to 10 days prior to harvest.

Watch Out for Drift

Grain sorghum is sensitive to herbicide drift

from other crops. Glyphosate, Clincher, Ricestar,

Select and propanil are especially damaging to

grain sorghum in low rates. Symptoms may range

from stand losses to non-uniform growth and

delayed maturity. Grain sorghum affected by

Figure 8-4. Glyphosate drift on grain sorghum.

UPDATED 4-2015 5

Figure 8-5. Grain sorghum injury from Laudis herbicide POST. Grain sorghum fields next to cornshould be monitored carefully for drift from cornherbicides.

low rates of grass herbicides often suffers much

more damage from sorghum midge due to the

non-uniform growth and flowering throughout

the field.

Herbicide Resistance

Herbicide-resistant weeds are becoming more

of a problem in all crops. Pigweeds (Palmer ama-

ranth) with resistance to atrazine are common in

other states but have not been found in Arkansas

at this time. There are some johnsongrass popula-

tions in Arkansas with resistance to ALS herbicides

and glyphosate. Grain sorghum should not be

planted in fields containing potentially high

populations of johnsongrass if at all possible.

Much of the Palmer amaranth in Arkansas is

resistant to the ALS mode of action herbicides

such as Peak as well as glyphosate. As more corn

and grain sorghum are grown in Arkansas with

more dependence on atrazine, triazine resistance

is more likely. If you suspect resistance after a

herbicide application, treat with an alternate

herbicide and contact your county Extension

agent. The University of Arkansas will collect

samples and test for resistance. Do not let the

weeds go to seed in the field.

UPDATED 4-2015 6

Table 8-1.

Wee

d Respon

se Ratings for Grain Sorghum

Herbicides

SEDG

ES Yellow Nutsedge 0 - 9 7 7 6 7 7 0 9 10 0 0 0 5 5 7 0 0 3*Rating

will be 0 on AL

S inh

ibitor-resistant w

eeds (G

roup 2).

Rating scale

– 0 = No Co

ntrol 1

0 = 10

0% Con

trol.

**Repeat a

pplication

may be needed to

achiev

e these ratings.

BROA

DLEAVE

S

Velvetleaf 8 - 4 7 7 6 6 10 8 6 7 8 8 6 7 7 8 7 7 7

Smartweed 9 - 5 4 4 8 6 9 8 6 7 5 9 0 9 9 9 9 9 5

Sicklepod 8 5 0 8 8 8 8 9 8 4 5 8 8 - 8 8 0 3 6 9

Purslane 9 - 6 9 9 9 9 9 - 7 8 9 - - 9 9 7 - - 8

Prickly Sida 9 7 6 9 9 9 9 9.5 8 7 8 8 - - 8 8 7 - 8 3

Pigweed sp. 9 9 8 9 9 9 9 10 4 0 0 8 9 4 9 9 0 5 8 9

Morningglory 8 8 2 8 8 8 8 9 8 5 6 9 9 8 9 8 4 7 8 4

Lambsquarters 9 7 6 9 9 9 9 9 8 5 6 8 9 6 8 8 5 8 8 9

Horsenettle 5 - 3 3 3 3 3 3 - - - 4 6 - 4 4 0 4 5 7

Honeyvine Milkweed 6 - - 6 6 5 6 7 - - - 9 9 - 6 6 5 7 7 -

Common Ragweed 9 - 7 9 9 9 9 9 8 5 5 9 9 6 8 8 8 7 8 8

Cocklebur 9 - 0 8 8 8 8 9 3 - - 9 8 - 9 9 9 9 9 4

Bigroot Morningglory 4 5 2 4 4 3 4 4 - - - 3 8 4 4 4 3 7 7 -

GRAS

SES

Shattercane 0 - 7 7 7 7 7 5 0 0 0 0 0 0 0 0 0 0 0 0Seedling Johnsongrass 2 - 6 4 6 3 6 3 0 3 3 0 0 0 4 3 0 0 0 8

Ryegrass - - 9 9 8 8 8 9 0 - - 0 0 - 6 5 0 0 0 7

Rhizome Johnsongrass 0 0 0 0 0 0 0 0 0 3 3 0 0 0 0 0 0 0 0 0

Red Rice 8 7 7 9 8 9 8 8 0 0 0 0 0 0 9 9 0 0 0 9

Goosegrass 6 8 9 9 9 9 9 7 0 3 3 0 0 6 7 6 0 0 0 9

Foxtail 6 8 9 9 9 9 9 8 0 0 0 0 0 7 8 7 0 0 0 8

Fall Panicum 3 7 9 9 9 8 9 8 0 3 3 0 0 6 6 5 0 0 0 8

Crabgrass 7 8 9 9 9 9 9 9.5 0 3 3 0 0 7 8 6 0 0 0 9

Broadleaf Signalgrass 4 7 8 8 7 7 8 9.5 0 3 3 0 0 9 9 6 0 0 0 9

Barnyardgrass 6 8 8 8 9 8 9 9.5 0 0 0 0 0 8 8 6 0 0 0 9

MODE OF ACTION 514, 1

515 15, 5

15, 5

15, 5

15, 5

15, 5

, 27

2 2 2 4 4 4 4, 5 5 6 6

6, 27

22

HERB

ICIDESPreemergence

Atrazin

eVe

rdict

Dual Magnum/Outloo

kDu

al II Magnum + Atra

zine

Degree

+ Atra

zine

Micro-Tech + Atra

zine

Outlook + Atra

zine

Lexar

Postem

ergence

Peak

Perm

itPe

rmit Plus

2,4-D

Banvel or Clarity

Facet L

Facet L

+ Atrazin

eAtrazin

e + oil

Basagran

Buctril

Huskie

Paraqu

at directe

d or Hood

7

Table 8-2. R

ecom

men

ded

Herbicides for W

eed Con

trol in

Grain Sorghum

Crop, Situation, and

Active Chem

ical

Formulated Material

Method of Application

Per B

roadcast Acre

Weeds Controlled

Per B

roadcast Acre

Time of Application

and Precautions

GRAIN SO

RGHU

MPreplant

glyphosate @ 1 lb/A

Emerged we

eds.

Glyphosate (4 lb/gal

Prep

lant for veg

etation

Apply

in low volum

e – 5 to 10 gp

a.formulations)

knockdow

n.32

oz/A

.

glyph

osate + 2,4-D @ 1.0

Annual grasses and broa

dleaf

Glyphosate (4 lb/gal

Same as abo

ve.

Improved

con

trol of h

orsewe

ed, curly do

ck+ 0.50 lb/A

weeds.

formulations)+ 2,4-D

and primrose.

32 oz/A

+ 1 pt/A

of 4SL

2,4-

D am

ine.

S-metola

chlor

@ 0.9 to

Red rice, yellow

nutsedg

e,Dual Magnum 7.64 EC

orC

inch

Incorporate thorou

ghly in

Use with Concep-treated sorghum

seed

1.4lb/A

annual grasses and pig

weed

.7.64 EC

top 2 inc

hes within 14

days

only. If broad

leaf w

eeds emerge

, use 2,4-D

1 to 1.6 pt/A

.be

fore plan

ting.

or atra

zine po

stemerge

nce.

dimethe

namid

@ 0.56 to

Red rice, yellow

nutsedg

e,Ou

tlook 6 E

Apply

up to 45 da

ys

Use with Concep-treated seed only.

0.98

lb/A

annual grasses and pig

weed

.12

to 21 oz/A.

prep

lant.

Preemergence

S-metola

chlor

@ 0.95 to

Annual grasses and pig

weed

.Dual Magnum 7.64 EC

orC

inch

At plan

ting.

Use with Concep-treated sorghum

seed

1.9 lb/A

For red rice or y

ellow

nutsedg

e7.64 EC

only.

May be tank m

ixed with atra

zine

use ppi treatment a

bove.

1 to 2 pt/A

.according

to labe

l direction

s or m

ay be fol-

lowed

with atra

zine or 2,4-D fo

r broad

leaf

control as recommen

ded be

low.

S-metola

chlor

+ atra

zine

Annual grasses and broa

dleaf

Bicep II Magnum 5.5 L or

At plan

ting.

Use with Concep-treated seed only. Good

@ 1.25 + 1 lb

/Awe

eds. Fo

r red rice or y

ellow

CinchATZ 5.5 F

treatments for a

verage weed infestations.

nutse

dge, use Dual M

agnu

m1.3 qt/A.

Howe

ver, if r

ed rice is a proble

m, u

se Dual

ppi and atra

zine early post if needed. If

ppi above.

heavy c

ockle

bur a

nd m

ornin

gglory p

ressure

exists, use atrazin

e preemergence at pre-

emergence rates b

elow or use atra

zine early

post as lis

ted below

.

atrazin

e @ 1 lb/A

Germ

inating annual grasses a

ndAtrazin

eAt plan

ting.

Do not pla

nt fall cover crops. Do

not pla

ntmost annual broadlea

f weeds,

1 qt/A 4L or 1.1

lb/A Nine

-0.

crops othe

r than corn in treated

fields

during

includ

ing co

ckleb

ur, annual

the sa

me season. Thoroughly

till soil befo

repla

nting any sp

ring cro

p oth

er than co

rn or

mornin

gglory a

nd sicklep

od.

sorghum. P

lanting deeper than 1 inch will

increase safety m

argin

. Do not use on coarse-

textured so

ils (sand, loa

my s

and, sandy loam)

or on any s

oil with less than 1% o.m. F

orsandy s

oils, see A

Atrex +

oil b

elow. All a

trazin

elab

els have been re

vised because of surfac

eand groundwa

ter co

ncerns. S

pecia

l precau-

tions are re

quired on new

labels.

UPDATED4-2015

Table 8-2. R

ecom

men

ded

Herbicides for W

eed Con

trol in

Grain Sorghum

(con

t.)

Crop, Situation, and

Active Chem

ical

Formulated Material

Method of Application

Per B

roadcast Acre

Weeds Controlled

Per B

roadcast Acre

Time of Application

and Precautions

Preemergence [cont.]

saflufenacil @

0.022

toPigw

eed, velv

etlea

f, mornin

g-Sharpen

Burndo

wn up to preem

er-

For b

est b

urnd

own results, tan

k mix with

0.044 lb/A

glory and horsewe

ed.

1 to 2 oz/A

.ge

nce. Do not a

pply Sh

arp-

glyph

osate or paraq

uat. An

MSO

and

AMS

en over the

top of emerge

dmust b

e used

for b

urnd

own.

sorghu

m.

See lab

el for further re

commen

dations and

restriction

s.

dimethenamid + saflufenacil

Annual grasses, pig

weed

,Verdict

Burndo

wn up to preem

er-

Rainfall or o

verhea

d irriga

tion is requ

ired for

@ 0.31 to 0.62 + 0.04

4 to

velve

tleaf, m

ornin

gglory an

d10

oz/A

.ge

nce. Do nota

pply Ve

rdict

activation

. Verdic

t can

be used

as a bu

rn-

0.088 lb/A

horsew

eed.

over th

e top of emerge

ddo

wn th

at leaves beh

ind re

sidua

l con

trol.

grain

sorgh

um.

For b

est b

urnd

own activity, tan

k mix with

glyph

osate an

d use MSO

1 pt/A

+ AMS. On

med

ium to

fine

soils, the rotation interval to

soybea

ns is 30 da

ys if you

were to lose th

egrain

sorgh

um crop.

Use with Con

cep-tre

ated

see

d.Se

e lab

el for restriction

s.

dimethenamid

For a

nnual grasses and

pig-

Outlook 6E

At plan

ting.

Use with Concep-treated seed only. Rates

0.56 to

0.98 lb/A

weed. F

or re

d rice or yellow

12 to

21 oz/A.

depend on percent organic matter. See

nutse

dge, use ppi tre

atmen

t.label.

dimethenamid + atrazin

eAn

nual grasses and broa

dleaf

Guardsman Max 5L

At plan

ting.

Use with Concep-treated seed only.

package mix

weeds. Fo

r red rice or y

ellow

2.5 pt/A.

nutse

dge, use ppi tre

atmen

t.

Postem

ergence

2,4-D am

ine @

0.5 lb/A

Most b

roadlea

f weeds such as

2,4-D am

ine

Apply

whe

n we

eds are

May be ap

plied

broad

cast overtop to

mornin

gglory, cockleb

ur and

1 pt/A of 4

lb/gal 2,4-D am

ine.

small and

sorgh

um 6 to

12

sorghu

m not over 8

inches. D

irecte

d ap

pli-

sickle

pod.

Do not use a surfacta

nt or o

il.inc

hes.

cations later w

ith drop no

zzles

. Do no

t treat

when

sorgh

um is in bloo

m. A

VOID DRIFT.

Do not app

ly du

ring very active growth, i.e.,

when

com

bination

of g

ood mois

ture, w

arm

tempe

ratures an

d hig

h nitroge

n exist, o

rexcessive

injury may re

sult. Follow all State

Plant B

oard regulations.

dicam

ba @

0.25 lb/A

Most b

roadlea

f weeds such as

Banvel or C

larity 4 SL

From

grain sorghu

m emer-

Ground application

only

. Drift is extrem

elymornin

gglory, cockleb

ur and

0.5 pt/A.

gence up

to 8 inches ta

ll.toxic

to so

ybeans. D

o not apply after soy-

sickle

pod.

Do not use a surfacta

nt or o

il.Be

st results on we

eds

beans b

egin to emerge in general area. Less

3inc

hes or less.

toxic

than 2,4-D to co

tton. Follow all State

Plant Board regulations.

8

UPDATED4-2015

9

Crop, Situation, and

Active Chem

ical

Formulated Material

Method of Application

Per B

roadcast Acre

Weeds Controlled

Per B

roadcast Acre

Time of Application

and Precautions

atrazin

e @ 1 to

2 lb/A

Most small-seeded an

nuals

.AA

trex, Atrazin

eAp

ply from

sorgh

um emer-

Do not

apply

if grain

sorghu

m is taller th

anMore effective on broa

dleaf

1.25

to 2.5 lb/A 80W

or 1

to 2 qt/A

gence up

to “c

lose in.” A

pply

12inc

hes. Do

not

graze tre

ated area

s or fee

dwe

eds. Go

od contro

l of p

igwee

d,4L or 1

.1 to

2.2 lb/A Nine

-0. U

se low

before wee

ds excee

d 1½

forag

e fro

m tre

ated lan

d within 21

days o

f app

li-cockleb

ur, a

nnual m

ornin

gglory,

rate on silt loa

m soil and

high

rate

inche

s in

heigh

t. Best grass

cation. After

June

10,

do not

plant

crops othe

rvelve

tleaf, spurre

d anod

a, prickly

on clay

soil. N

o surfa

ctant is re

com-

control obtained before

than corn or g

rain sorghu

m the

following

year.

sida, smartweed, sick

lepod

and

men

ded on

labe

l.grass we

eds exceed ½

Do not use on sands o

r sandy loam

soils.

red rice.

inch.

For these so

ils, use atrazin

e and crop oil

concentrate belo

w. Do no

t app

ly mo

re th

an2.5

lb/A active atr

azine

per se

ason

.

atrazin

e @ 1.2 lb/A + oil

Same as above.

AAtrex, Atrazin

e +

Same as abo

ve.

Same

as a

bove but

may b

e used

on sand

yconcentra

teCrop Oil Concentrate

loam

soil. Le

ss lik

ely to

cause injury to milo or

1.5 lb/A 80W or 1

.2 qt/A

4L or 1.33

carry

over to

sensitiv

e follow

crop

s.

lb/A Nine-0 + 1 qt/A

oil c

oncentrate.

S-metola

chlor + atra

zine @

Annual grasses, pig

weed, annual

Dual Magnum + AAtrex

Before sorgh

um re

ache

sSo

me injury m

ay occur with high

er ra

tes on

0.75 to

1.3 lb/A + 1 to

1.2

mornin

gglory, velve

tleaf, smart -

0.8 to 1.4 pt/A

+ 1/2 qt/A

.12

inche

s tall. Be

st grass

lighte

r soils.

lb/A

weed and sicklep

od.

control obtain

ed before grass

weed

s exceed ½

inch.

halos

ulfuron @

0.047 lb/A

Yellow nutse

dge, flatsedg

e an

dPermit or Halom

ax 75 WG

Apply

to emerge

d we

eds.

Aerial or g

roun

d ap

plication. Avoid drift to

hemp sesbania.

1 oz/A.

soybea

ns.

Add a no

nionic

surfacta

nt or c

rop oil

concen

trate.

halos

ulfuron + dica

mba @

Ragw

eed, horsewe

ed, n

utsedge

Yukon 67.5 DG

From

sorgh

um emerge

nce

Ground application

only

. Drift is extremely

0.075 + 0.2 lb/A

and broadle

af weeds.

6 oz/A.

up to

8inc

hes tall. Be

sttoxic

to soybeans.Do

not apply after soy-

results on we

eds 3inc

hes

beans b

egin to emerge in general area. Less

or le

ss.

toxic

than 2,4-D to co

tton. Follow all State

Plant Board regulations.

prosulfuron @

0.027 lb/A

Most b

roadlea

f weeds inclu

ding

Peak 57 WDG

Apply

to actively grow

ingWill no

t con

trol A

LS-re

sistan

t wee

ds.

triazine

-resis

tant biotypes.

0.75

oz pe

r acre. Add

0.25%

sorghu

m betwe

en 5 and

20

See cro

p rotat

ion se

ction

for p

recaution

s abo

ut no

nionic

surfacta

nt.

inche

s in he

ight a

nd before

rotat

ional cro

ps.

head

emerge

nce.

Do not

apply

to so

rghu

m un

der s

tress from

moisture or co

ld we

ather.

Do not

apply

to so

rghu

m tha

t has bee

n tre

ated

with

an organ

opho

spha

te ins

ecticide

at p

lanting

or within 15

days o

f a post em

erge

nce orga

no -

phosph

ate insecticid

e ap

plication.

bentazon @

0.75 to 1 lb/A

Cockleb

ur, ragwe

ed, jimsonw

eed,

Basagran 4 S

Poste

mergence. See label fo

rMa

y be tan

k mixe

d with

atrazine

. See

labe

l.sm

artweed, prick

ly sid

a, velve

tleaf

0.75

to 1 qt/A

. specific

timing

for w

eed

Best tre

atmen

t for sm

artwee

d.and yellow nutse

dge.

desired.

UPDATED4-2015

10

Table 8-2. R

ecom

men

ded

Herbicides for W

eed Con

trol in

Grain Sorghum

(con

t.)

Crop, Situation, and

Active Chem

ical

Formulated Material

Method of Application

Per B

roadcast Acre

Weeds Controlled

Per B

roadcast Acre

Time of Application

and Precautions

Postem

ergence [cont.]

bentazon + atra

zine @ 0.5

Most broadlea

f weeds.

Basagran + Atrazin

ePo

stemerge

nce fro

m emer-

Use low

rate

on sm

all wee

ds and

high

er ra

te on

to 0.75 + 0.5 to 0.75 lb/A

1 to 1.5 pt/A

+ 1 to

1.5 pt/A

4L or 0.6

gence to boo

t.large

r wee

ds. A

ll atra

zine lab

els have be

ento 0.9 lb/A 80W

or 0

.55 to 0.8

lb/A

revis

ed becau

se of surfac

e an

d grou

ndwa

ter90

DF. A

dd crop oil con

centrate.

concerns. S

pecia

l precaution

s are re

quired on

Packag

e mix is Laddock. 2½ pt/A

new lab

els.

Ladd

ock = 0.5 to 0.5 lb/A a.i. rate.

brom

oxynil @

0.25 to 0.375

Cockleb

ur, sm

artweed, mornin

g-Buctril 2 E

Poste

merge

nce to wee

ds in

Use hig

h rate on mornin

gglories

and

pig-

lb/A

glories a

nd pigw

eed.

1 to 1½

pt/A. O

n larger w

eeds, tank

seed

ling (2- to 4-lea

f) sta

ge.

weed

. Weeds must be s

mall.E

xpect som

emix with 0.5 lb/A active Atra

zine.

temporary burn.

brom

oxynil +

pyrasulfotole

Annual broadle

aves inclu

ding pig

-Huskie

Apply

on or after 3

-leaf stage

Use hig

h rate on mornin

gglories

and

pig-

@ 0.175 to

0.22 lb/A + 0.03

weed and mornin

gglories

. 12.8 to 16 oz/A. A

dd 0.25%

NIS.

until grain

sorgh

um re

ache

swe

ed. W

eeds must be s

mall. E

xpect som

eto 0.39 lb/A

30 inches ta

ll, or flag

leaf

temporary injury if ta

nk mixe

d with atrazine

.em

erge

s.

paraquat @

0.5 lb/A

Annual grasses a

nd broadlea

fParaquat (2 or 3 lb/gal

After s

orgh

um is 12 inc

hes.

Directed spray with hoods. Spray must

weeds.

formulations)

not touch more than lower 3 inches of

32 or 2

1 oz/A. A

dd 0.25%

nonion

icstalk. Som

e injury will occur.

surfa

ctant.

quinc

lorac @

0.25 to 0.375

Annual grasses a

nd broadlea

fFacet L

Apply

to wee

ds less th

anAp

ply prior to 12

-inch grain sorghu

m.

lb/A

weeds.

22 to 32 oz/A.

2inc

hes tall.

Tank m

ix with 1 lb/A atra

zine for improved

control. Do

not drift o

n cotton or to

matoe

s.

Preharvest

sodiu

m chlo

rate @

4.5 to

6De

siccation of green ve

getation.

Sodium

Chlorate

7 to 10 days prior to harvest.

Use a lab

eled bran

d an

d follow lab

el direc-

lb/A

Several brands a

nd trade names

tions.

available. 2 gal of 3 lb/gal or 1 gal of

6lb/gal.

carfe

ntrazone @

0.016 lb/A

Desic

cation of m

ornin

gglories

.Aim 2 EC

3 days prior to harvest.

Coverage

is im

porta

nt. U

se 10 ga

llons of

1 oz/A.

spray solution

per acre. Can

be tank m

ixed

with sod

ium chlo

rate.

glyphosate @ 1 to 1.3 lb/A

Desic

cation of green ve

getation.

Glyphosate (4 lb/gal formulations)

7 days prior to harvest.

Coverage

is im

porta

nt. U

se 10 ga

llons of

32 to 40 oz/A.

spray solution

per acre. Can

be tank m

ixed

with sod

ium chlo

rate.

glyphosate + carfe

ntrazone

Improved desicc

ation

of vine

s/Glyphosate (4 lb/gal formulations)

7 days prior to harvest.

Coverage

is im

porta

nt. U

se 10 ga

llons of

@ 1 lb/A + 0.016 lb/A

mornin

gglories

.+ Aim 2 EC

spray solution

per acre. Can

be tank m

ixed

32 oz/A

+ 1 oz/A

. with sod

ium chlo

rate.

UPDATED4-2015

UPDATED 4-2015 11

Figure 8-6. Common Weed Seedlings in Grain Sorghum

smooth pigweed, redroot pigweed

Palmer amaranth

tall waterhemp

common lambsquarters

common cocklebur

ivyleaf morningglory

UPDATED 4-2015 12

Figure 8-6. Common Weed Seedlings in Grain Sorghum (cont.)

pitted morningglory

palmleaf morningglory

entireleaf morningglory

purple moonflower

smallflower morningglory

bigroot morningglory

UPDATED 4-2015 13

spotted spurge

prickly sida

Pennsylvania smartweed

nutsedge

large or southern crabgrass

goosegrass

UPDATED 4-2015 14

Figure 8-6. Common Weed Seedlings in Grain Sorghum (cont.)

broadleaf signalgrass

barnyardgrass

fall panicum

johnsongrass

red rice