Downy Brome Management in Montana Agriculture Cropland Weed Research Montana State University Edward Davis, Fabian Menalled

Presentation Outline Biology and identification of brome species. Weedy characteristics Management considerations. Herbicide options. Herbicide label rates and application timing. MSU field trial results.

Weed Science Terminology For Brome Species “Cheatgrass”  Downy brome Bromus tectorum  Japanese brome Bromus japonicus  Cheat Bromus secalinus Not found in MT

Cheat Cheat is in Oklahoma, not MT! Pictures from Interactive Encyclopedia of North American Weeds (Bromus secalinus) Not found in MT!!! Weed scientists refer to Bromus secalinus as Cheat. However, they refer to Bromus tectorum as Downy brome or Cheatgrass.

Cheat Bromus secalinus Slide courtesy of Dr. Phil Stahlman, KSU Not found in MT

Downy brome Pictures from Interactive Encyclopedia of North American Weeds (Bromus tectorum)

Japanese brome Pictures from Interactive Encyclopedia of North American Weeds (Bromus japonicus)

Japanese brome Downy brome Downy brome (Bromus tectorum) Taller ligule than Japanese, more serrated ligule than Japanese Japanese brome (Bromus japonicus) Shorter ligule than Downy, less serrated ligule than Downy More hairy, longer hairs than Downy, especially on underside of leaf Pictures from Interactive Encyclopedia of North American Weeds

Downy Brome Bromus tectorum

Downy brome Bromus tectorum Slide courtesy of Dr. Phil Stahlman, KSU

Japanese brome Bromus japonicus Slide courtesy of Dr. Phil Stahlman, KSU

Japanese brome Slide courtesy of Dr. Phil Stahlman, KSU

Cheat (Chess) Bromus secalinus Downy brome Bromus tectorum Japanese brome Bromus japonicus

Downy Brome (cheatgrass) Bromus tectorum Winter annual grass weed Reduces crop yield Reduces soil moisture

Downy brome  Found mostly in 6 to 22 inch precipitation zones  Grows at elevations up to 8850 ft  Prefers coarse textured soils, but grows well on all but extremely heavy or highly saline soils

Downy Brome Up to 400 seed/plant 500# seed/a –125 million/a –2,870/sq.ft. Matures 4 wk earlier than wheat Initial dormant period Short soil seed life –2-3 yrs.

Reasons Why Annual Bromes Are Increasing  Conservation tillage  Increased fertilization  Shorter, less competitive varieties  Highly effective broadleaf herbicides  Drought years,CRP

Cultural Control Practices Management  Crop rotation  Delayed seeding  Winter wheat row spacing  Winter wheat seeding rates  Competitive wheat cultivars  Fertilizer timing and placement

Weed Response to Crop Rotation Sidney, NE Lyon and Baltensperger 1995

Delayed Seeding  Effective for downy brome control in only 1 of 6 years in Colorado.  Lower yield potential and higher risks of winter kill and wind erosion.  In Oklahoma, a 4-wk delay for cheat control resulted in economic loss. Anderson 1996 Ferreira et al. 1990

Row Spacing and Seeding Rate 20 site-years in Oklahoma lb/A lb/A ---- Epplin et al. 1996

Wheat Seeding Rate Affects Cheat 20 site-years in Oklahoma Epplin et al. 1996

Downy Brome Response to N Pendleton, Oregon R asmussen 1995

N Timing Affects Downy Brome Akron, CO Anderson 1991

N Placement on Downy Brome Wyoming Miller 1990

Fertilizer Placement Pendleton, OR Rasmussen 1995

Weed-Crop Competition  resource availability  plant and tiller density  environmental conditions  winter wheat competitiveness  time of emergence relative to wheat Winter annual grass interference is a function of several factors including:

Weed-Crop Competition  Moderate weedy brome infestations reduce winter wheat yields by 20 to 40%; dense infestations up to 90%.  Yield losses are most severe when resources are limited and weeds and wheat emerge simultaneously.

Weed-Crop Competition  Research in Kansas and Alberta  With normal wheat stands and adequate resources, low to moderate infestations of downy brome that emerge 3 weeks or later than winter wheat usually do not reduce wheat yield. Blackshaw 1996 Stahlman and Miller 1990

Winter Wheat Yield Loss

Cultivar Competitiveness  Winter wheat cultivars vary widely in their competitiveness with weeds.  Plant height is the characteristic most associated with increased competitiveness.  Early plant growth, tillering ability, and leaf area also are important.

Grass weed response to herbicides Downy brome Japanese brome Less susceptible More susceptible

Maverick  Sulfosulfuron  ALS Enzyme Inhibitor (blocks protein synthesis)  The first selective herbicide developed for control of winter annual brome species in wheat.  Controls several common winter annual broadleaf weeds  Restrictive crop rotation intervals

Olympus  Propoxycarbazone-sodium  ALS Enzyme Inhibitor (blocks protein synthesis)  Main target weeds are cheat, downy brome and Japanese brome as well as a number of key broadleaves.  Olympus may control wild oat and suppress jointed goatgrass.  Olympus FLEX is a mixture of propoxycarbazone-sodium and mesosulfuron- methyl.

Osprey  mesosulfuron-methyl  ALS enzyme inhibitor (blocks protein synthesis)  Main target weeds are wild oat, Persian darnel and Italian ryegrass as well as a number of key broadleaves.  Osprey will suppress downy brome.

Wild oat Green foxtail Yellow foxtail Barnyardgrass Downy brome Japanese brome Persian darnel Quackgrass Foxtail barley Beyond (CL)CCCCCCC EverestCCSSC MaverickSC/S C Olympus FallS/C C/CS/SC/C Olympus SprS/CS/SC/CS/SC/C OlympusFlexCPCCCC C OspreyCSC What do the herbicide labels say?

Environmental Stresses  Stress reduces postemergent herbicide effectiveness.  Effectiveness generally affected more by moisture than temperature stress.  Cold temperatures after application increases risk of crop injury.  Low density weed populations generally are more easily controlled than high density populations.

October 21, 2004 Amsterdam, MT

Maximum Single Application use Rates for Downy Brome Control in Rampart Winter Wheat. Fall Applied, Amsterdam 2005 HerbicideOz Product% ControlBu/acre Olympus Osprey Maverick OlyFLEX Untreated034*

April 7, 2005 Amsterdam, MT

Maximum Single Application use Rates for Downy Brome Control in Rampart Winter Wheat. Spring Applied, Amsterdam 2005 HerbicideOz Product% ControlBu/acre Olympus Osprey Maverick OlyFLEX Untreated034*

Maximum Single Application use Rates for Downy Brome Control in Rampart Winter Wheat. Fall Applied, Amsterdam 2005 HerbicideOz Product% Control% Injury OlyFLEX OlyFLEX Finesse OlyFLEX OlyFLEX Finesse Untreated00

Maximum Single Application use Rates for Downy Brome Control in Rampart Winter Wheat. Spring Applied, Amsterdam 2005 HerbicideOz Product% Control% Injury OlyFLEX OlyFLEX Finesse OlyFLEX in OlyFLEX Finesse Untreated00

Product Common Name % AI Olympuspropoxycarbazone-sodium70% Ospreymesosulfuron4.5% Olympus FLEX propoxycarbazone-sodium mesosulfuron 6.75% 4.5%

Herbicide Label Restrictions for Application Rates HerbicideField Rate Min appl. Field Rate Max appl. Maximum per season Olympus Osprey Olympus FLEX

Possible Sequential Applications with Olympus Followed by Olympus Fall Applied Spring 0.0 oz Spring 0.3 oz Spring 0.6 oz Spring 0.9 oz Max per yr Olympus 0.6 oz 0.6 oz Olympus 0.9 oz

Possible Sequential Applications with Olympus followed by Osprey Fall AppliedSpring Osprey 3.2 Spring Osprey 4.5 Maximum per year Olympus 0.6 oz Oly 0.6 Osprey 3.2 Oly 0.6 Osprey 4.5 Oly 1.2 Osprey 4.5 Olympus 0.9 oz Oly 0.9 Osprey 3.2 Oly 0.9 Osprey 4.5 Oly 1.2 Osprey 4.5

Possible Sequential Applications with Olympus followed by Osprey Fall Applied Spring OlyFLEX Spring OlyFLEX Maximum per year Olympus 0.6 oz Oly 0.9 Osprey 3.0 Oly 0.94 Osprey 3.5 Oly 1.2 Osprey 4.5 Olympus 0.9 oz Oly 1.2 Osprey 3.0 Oly 1.24 Osprey 3.5 Oly 1.2 Osprey 4.5

January 13, 2006 Moccasin, MT

April 21, 2006 Moccasin, MT

Treatment% control % control Yield Bu/acre Olympus 0.6 Fall Olympus 0.6 Fall Olympus 0.6 Spr Olympus 0.6 Fall Olyflex 3.5 Spr Olympus 0.6 Fall Olyflex 3.2 Spr Olyflex 3.5 Fall Olyflex 3.5 Fall Osprey 3.2 Spr Maverick 0.5 Fall Maverick 0.66 Spr Untreated0017

Acknowledgement Phil Stalman, Kansas State University Dan Ball, Oregon State University Brian Jenks, North Dakota State University Joe Yenish, Washington State University

Thanks MABA – MGEA Agricultural Chemical Industry Montana Agricultural Producers

Questions