Cheatgrass: Biology, Ecology, and Management

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

2. Cheatgrass (Bromustectorum) • Annual • Large and open panicle • Drooping • ½ inch awns

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

4. Impacts Across Montana Crops Rangeland CRP

5. 56.7 million acres in western states • Expanding by 14% per year • -Duncan et al. 2004

6. 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

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

8. 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.

9. Cheatgrass Seeds Germinate Quickly Days to 25% germination Days to 25% germination after exposure to freezing temperatures (Jan. 31-Feb. 15) ***Cheatgrass and medusahead had begun to germinate in the field by February 10 Wilson et al. 1974. J. Range Manage. 27(2):120-122

10. Cheatgrass Grows Fast Arredondo et al. 1998. J. Range Manage. 51(5):584-589

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

12. 1 2 Cheatgrass 1 2 Bluebunch wheatgrass Photo courtesy of Lori Ziegenhagen, USDA-ARS

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

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

15. Cheatgrass Management • Target cheatgrass in spring and fall X Prevent seed development! Deplete seed bank!

17. 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

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

19. Chemical

20. 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

21. Targeting Cheatgrass with Glyphosate Number of plants/0.1m2 Sprayed on May 11, 2009 Non-sprayed control Data pooled across 3 sites

22. Chemical Control

23. Effect of Imazapic on Annual Grasses* *22% cheatgrass, 15% annual bluegrass, 15% medusahead Shinn and Thill. 2002. Weed Tech. 16(2): 366-370

24. 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

25. Competitive Effects of Seeded Grasses Whitson and Koch. 1998. Weed Tech. 12(2): 391-396

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

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

28. 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!

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

30. 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

31. Prescribed Fire • Hot fire will destroy seeds on soil surface, in the litter, and on the plant • Reduce germinable seeds by 98-100% • Seeds buried in the soil will be protected • Fire can reduce litter accumulation

32. 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

33. 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

34. Thank you! Questions? Jane Mangold 994-5513 jane.mangold@montana.edu