Cheatgrass: Biology, Ecology, and Management Jane Mangold Extension Invasive Plant Specialist Department of Land Resources and Environmental Sciences

Cheatgrass (Bromus tectorum)  Annual  Large and open panicle  Drooping  ½ inch awns

Japanese brome (B. japonicus)  Large and open, heavy panicle  Drooping  < ½ inch awns

Impacts Across Montana Rangeland CRP Crops

 56.7 million acres in western states  Expanding by 14% per year -Duncan et al. 2004

Cheatgrass Origin and Distribution  Native of southwestern Asia  Introduced to North America in several independent events Contaminated seed Ship ballasts  Problematic in western U.S. and Canada and northern Mexico

Weedy Characteristics: Winter Annual  Germinates/emerges in fall  Resumes growth in early spring  Produces seed May-June  Plant dies, seed dormant until fall

Cheatgrass Produces Lots of Seed  400 – 4,000 seeds/plant  Short seed life (2-3 years)  Dispersed by humans, animals, wind, machinery, contaminated straw/hay, etc.

Cheatgrass Seeds Germinate Quickly Days to 25% germination SpeciesDays Cheatgrass3.8 a Medusahead5.5 b Smooth brome6.6 c Crested wheatgrass6.9 cd Siberian wheatgrass7.3 d Bluebunch wheatgrass8.1 e Days to 25% germination after exposure to freezing temperatures (Jan. 31-Feb. 15) Days *** 5.5 b 4.3 a 4.9 a 6.2 a ***Cheatgrass and medusahead had begun to germinate in the field by February 10 Wilson et al J. Range Manage. 27(2):

Cheatgrass Grows Fast Arredondo et al J. Range Manage. 51(5):

Cheatgrass Adjusts to Local Conditions Photo courtesy of Lori Ziegenhagen, USDA-ARS

Cheatgrass Bluebunch wheatgrass

Impacts Reduces plant diversity Reduces forage and crop yield and quality Alters fire regimes Ruins my socks!

Cheatgrass Alters Fire Regimes Increase in quantity and continuity of fuel Larger and more frequent fires Perennial species unable to recover Further increase in cheatgrass

Cheatgrass Management  Target cheatgrass in spring and fall X Prevent seed development! Deplete seed bank!

Control MethodEffectiveness Prevention Chemical Revegetation Mechanical Grazing/Mowing Biocontrol Prescribed Fire

Prevention  EDRR  Maintain healthy, competitive plant community Cheatgrass increases with removal of native perennial grasses and forbs (which can occur as a result of over-grazing)  Minimize disturbance  Limit spread of seeds

Chemical Control--Some Herbicide Tolerance Photo by Ed Davis, MSU Non-sprayed control Sprayed, but cheatgrass only suppressed

Chemical Herbicide Active Ingredient Trade Name Product per AcreApplication Timing Glyphosate Roundup Pro 6 to 12 ouncesEarly spring while other grasses are still dormant; after emergence in fall

Targeting Cheatgrass with Glyphosate Sprayed on May 11, 2009 Non-sprayed control  3 sites (Madison and Ruby Valleys)  3 reps/site  Sprayed at 0, 6, 8, 10, or 12 oz. Roundup/A  Sampled June 16-18, 2009

Targeting Cheatgrass with Glyphosate Sprayed on May 11, 2009 Non-sprayed control Number of plants/0.1m 2 Data pooled across 3 sites

Chemical Control Herbicide Active Ingredient Trade Name Product per AcreApplication Timing Glyphosate Roundup Pro 6 to 12 ouncesEarly spring prior while other grasses are still dormant Imazapic + glyphosate Journey 16 to 32 ouncesLate summer to early fall before emergence and prior to planting desirable species Imazapic Plateau 2 to 12 ouncesLate summer to early fall before emergence and prior to planting desirable species Sulfometuron methyl + chlorsulfuron Landmark 0.75 to 2.25 ouncesSpring or fall application followed by planting desirable species in fall (at least 3-6 months after spraying) Rimsulfuron Matrix 2 to 4 ouncesSpring or fall application followed by planting desirable species in fall (at least 7 months after spraying)

Effect of Imazapic on Annual Grasses* Rate (oz/ac) % Control 30 DAT % Control 60 DAT Density 60 DAT (plants/m 2 ) Biomass 60 DAT (g/m 2 ) 00a0a 0a0a 532 a 8a8a 470 b 67 b 179 b 23 a 875 c 80 b 164 b 16 a *22% cheatgrass, 15% annual bluegrass, 15% medusahead Shinn and Thill Weed Tech. 16(2):

Revegetation  Seeding desirable, competitive vegetation is necessary if very little desirable vegetation is remaining (<20-30% cover)  Must control cheatgrass Multiple years of control prior to revegetation

Competitive Effects of Seeded Grasses Seeding Treatment Perennial Grass Biomass (kg/ha) Cheatgrass Biomass (kg/ha) % Reduction Critana thickspike wheatgrass Bozoisky Russian wildrye Sodar streambank wheatgrass Luna pubescent wheatgrass Hycrest crested wheatgrass Unseeded control Whitson and Koch Weed Tech. 12(2):

Assisted Succession  Restoration of weed-infested rangeland may require multiple steps Cheatgrass/ annual forbs Introduced, competitive grass Native vegetation

 Disturbed soil typically increases cheatgrass  Multiple treatments or follow up with herbicide/grazing/mowing disked strips—notice brown, cured cheatgrass Mechanical Control

Grazing  Cattle, Sheep, and Goats Spring Accessible but not yet producing seed >2 defoliations each spring >2 consecutive years Winter Reduce mulch accumulation Energy and protein supplements required  Graze/mow before plants start to turn purple!

Grazing Scenario Dominated by cheatgrass Devoid of perennial vegetation Dominated by perennials Cheatgrass present 1) 2) In which scenario will be easier to manage cheatgrass?

Biocontrol  None currently available  Researching potential for soil and seed fungi Soil fungus Pyrenophora semeniperda “Black fingers of death” Kills cheatgrass seeds in soil Seed fungus Ustilaga bullata Infects germinating seeds Plant grows to maturity but doesn’t produce seeds

Prescribed Fire  Hot fire will destroy seeds on soil surface, in the litter, and on the plant Reduce germinable seeds by %  Seeds buried in the soil will be protected  Fire can reduce litter accumulation

Prescribed Fire  Risky due to timing Typically not enough fuel to carry fire at most appropriate time Damage perennial, desirable vegetation Potential for fire to get out of control  More promising for Japanese brome than cheatgrass

Integrated Cheatgrass Management  Prevention  Integrate tools to decrease seed production and seed bank over time  Revegetation is imperative where very little desirable vegetation is remaining  Persistence and intelligence—use your hands and your head!  More research is necessary in Montana

Thank you! Questions? Jane Mangold