What is the goal of weed control

in wheat?Joe Armstrong

OSU Extension Weeds Specialist

A “clean” field at harvest may not tell the whole story

The cost of dockageReduced prices

Wasted fuel

Reduced yields due to weed competition

Yield must also be a goal!

Yield losses from 1 weed/ft2

Italian ryegrass = 11%wild oats = 13%

jointed goatgrass = 17%cheat = 18%

rye = 22%Adapted from Fast, Medlin, and Murray (2009)

Yield losses from3 weeds/ft2

Italian ryegrass = 17%wild oats = 22%

jointed goatgrass = 20%cheat = 19%

rye = 41%Adapted from Fast, Medlin, and Murray (2009)

35

40

45

50

55

60

14 28 42 56 70 84 98 112 126 140 154 168

Days after planting

Whe

at y

ield

(bu/

ac)

Olympus

Maverick

Fall applications = highest yields

≥ 85% weed control

PRE & Early POST herbicides

FinesseAmber

MaverickAxiom

Prowl H2O

Untreated

Axial XL, 16.4 fl ozapplied December 2

Axiom, 8 ozapplied November 1

Timing is crucial with these products!

ALS-resistant ryegrass in OK

08-09: Confirmed in 17 counties

ALS-resistant Italian ryegrass

Treated with Axial XL

Potential for resistance to

Axial XL

Untreated 16.4 fl oz1x rate

32.8 fl oz2x rate

65.6 fl oz4x rate

CenterfieldBeyond @ 4 fl oz in fall

conventional varietyuntreated

Wheat x jointed goatgrass hybrids show the importance of

stewardship of the Clearfield trait

wheat hybrid jointed goatgrass

Contact informationJoe Armstrong

OSU Dept. of Plant and Soil Sciences

joe.armstrong@okstate.eduTwitter: @OSUWeedSci

www.weedscience.okstate.edu