Cheatgrass Biology, Ecology, and Management Fabián Menalled menalled@montana.edu 406-994-4783 Montana State
http://ipm.montana.edu/cropweeds
Presentation Outline Biology and identification of brome species Weedy characteristics Management considerations (crops)
Terminology For Brome Species Cheatgrass - Downy brome - Bromus tectorum Japanese brome Bromus japonicus Cheat Bromus secalinus Not found in MT
Cheatgrass Japanese brome
Japanese brome Cheatgrass Pictures from Interactive Encyclopedia of North American Weeds
Japanese brome Cheatgrass More hairy, longer hairs, especially on underside of leaf Pictures from Interactive Encyclopedia of North American Weeds
Japanese brome Taller ligule and more serrated ligule Cheatgrass Photos: courtesy of Dr. Phil Stahlman, KSU
Cheatgrass Wheat Membranous Ligule Auricules
Cheatgrass is a winter annual (but can behave as a summer annual)
Annuals Seed Reproductive growth Vegetative growth Flower
Summer Annuals Seed Spring Reproductive growth Vegetative growth Fall Flower Wild oat http://www.forestryimages.org
Winter Annuals Seed Spring Fall Reproductive growth Vegetative growth Summer Fall Flower Cheatgrass http://www.forestryimages.org
Perennials Seed Reproductive growth Vegetative growth Foxtail barley Flower http://www.forestryimages.org
Presentation Outline Biology and identification of brome species Weedy characteristics Management considerations (crops)
Cheatgrass in Montana CRP Crops Rangeland Urban
Why Annual Bromes Are Increasing? Reproductive success Conservation tillage Increased fertilization Shorter, less competitive crops Drought years CRP
Cheatgrass Reproduction Up to 400-4000 seeds/plant Short soil seed life (2-3 yrs.) Dispersed by wind, contaminated straw, farm machinery, etc
Photo courtesy of L. Ziegenhagen, USDA-ARS
Why Annual Bromes Are Increasing? Reproductive success Conservation tillage Increased fertilization Shorter, less competitive crops CRP Fires drought conditions
Presentation Outline Biology and identification of brome species Weedy characteristics Management considerations (crops)
Questions, so far?
Management
Management
Herbicide Options
Herbicide Performance Stress reduces herbicide effectiveness Affected by moisture & temperature Risk of crop injury (cold temperatures) Low density weed populations are more easily controlled than high density populations Risk of resistance
Cross Resistance to ALS herbicides - Kansas - Resistant Cheatgrass Susceptible Cheatgrass Resistant J. Brome Susceptible J. Brome Olympus 0.9 oz Olympus 9 oz Maverick 0.67 oz Beyond 4 oz PowerFlex 3.5 oz Control D. Peterson KSU
Management Resource management
No. or lb/acre N Placement on Cheatgrass Wyoming 1400 1200 1000 800 600 400 Bdcst Band 200 0 Plants Dry wt. Downy brome Miller 1990
Management Resource management Crop variety Row spacing Seeding density
Wheat yield (Bu/A) Row Spacing and Seeding Rate 20 site-years in Oklahoma 35 30 25 20 15 10 5 0 9 3 9 3 ---- 60 60 lb/a lb/a ------ -- 120 ---- lb/a 120 -- Row spacing lb/a ---- (inches) Weed Free Cheatgrass Epplin et al. 1996
Cultivar Competitiveness Cultivars vary widely in their competitiveness with weeds Plant height associated with increased competitiveness Early plant growth, tillering ability, and leaf area also are important
Management Crop rotation Resource management Crop variety Row spacing Seeding density
Cheatgrass density (no. m -2 ) Crop Rotation and Cheatgrass Density 1200 1000 800 600 400 200 0 1987 1988 1989 1990 1991 1992 1993 1994 Year Wheat-canola, no-till Continuous wheat, no-till Wheat-canola, till Continuous wheat, till (After Blackshaw 1994)
Crop Safety?
Pea field in north central MT Photo Courtesy P. Miller
Can We Manage Cheatgrass with SU Herbicides and Rotate Crops? Vs. sulfosulfuron Pyroxsulam
PowerFlex Broadleaf weed control kochia, prickly lettuce, wild mustard, tansy mustard, corn gromwell, catchweed bedstraw, common lambsquarters, field pennycress, tumble mustard, henbit Grass weed control Wild oat, cheatgrass, Japanese brome, cheat
Crop Rotation Study Herbicide application: May 16, 2007 Crop: winter wheat Stage: Tiller Rotational crops: lentil, chickpea, safflower, field pea, camelina, flax Planting date: Spring 2008. No-till Environment: prone to soil carryover with group 2 herbicides
FLAX CAMELINA PEA PowerFlex 2X Maverick 1X Maverick 2X PowerFlex 1X
CHICKPEA FLAX CAMELINA PEA LENTIL SAFFLOWER PowerFlex 2X Maverick 2X
GoldSky Pyroxsulam (PowerFlex) ALS inhibitor Fluroxypyr (Starane) Synthetic auxin Florasulam ALS, AHAS enzyme inhibitor Crop safener Spring wheat product Federal registration: August 2008
GoldSky Broadleaf weed control kochia, prickly lettuce, wild buckwheat, wild mustard, Russian thistle, Redroot pigweed, tansy mustard, corn gromwell, catchweed bedstraw, common lambsquarters Grass weed control Wild oat, yellow foxtail, Italian ryegrass, green foxtail, brome species
CAMELINA BARLEY CANOLA OAT LENTIL PEA GOLDSKY Crop Rotation Study
Visual Damage (%) 90 80 70 60 50 40 30 20 10 0 Lentil Canola Camelina Barley Field Pea Oat GoldSky 1X Goldsky 2X Everest 1x Everest 2x Rimfire 1x Rimfire 2x
Management Crop rotation Time of emergence Resource management Crop variety Row spacing Seeding density
Relative Time of Control In good stands with adequate resources, low to moderate infestations of cheatgrass that emerge 3 weeks or later than winter wheat do not reduce yield Blackshaw 1996 Stahlman and Miller 1990
Relative Time of Emergence
Crop rotation Time of emergence Management Time of control Resource management Crop variety Row spacing Seeding density
Is Application Timing Important?
Bozeman Huntley PowerFlex + Agral 90 + Ammonium sulfate 18.4 g ai/ha + 0.5%v/v + 1.7 kh/ha Olympus + Agral 90 44 g ai/ha + 0.5%v/v Maverick + Agral 90 35 g ai/ha + 0.5%v/v Early Fall Late Fall Early Spring Late Spring
Cheatgrass Control, Bozeman Fall Spring Fall Spring Fall Spring PowerFlex Olympus Maverick
Cheatgrass Control, Huntley Fall Spring Fall Spring Fall Spring PowerFlex Olympus Maverick
Integrated Management Weed Management Crop rotation Time of emergence Time of control Resource management Crop variety Row spacing Seeding density
Take Home Message Although herbicides provide good control of cheatgrass, you must develop an Integrated Weed Management (IWM) strategy to reduce the spread and impact of this species
Questions?