1. Integrated Weed Management— Managing for Healthy Plant Communities Jane Mangold Extension Invasive Plant Specialist Department of Land Resources and Environmental Sciences

2. What we’ll cover 1)Integrated Weed Management (IWM) What is IWM? Ecological framework for IWM 2)Healthy plant communities Healthy plant community defined Managing for a healthy plant community 3)Integrated management of cheatgrass

3. Integrated Weed Management Begin with the end in mind...  Kill the weed—Yes, but not the whole story  Healthy plant community that meets management objectives whitetop (hoary cress) infestation

4. Weed Management Herbicides Multiple classes of livestock Hand pulling Revegetation BiocontrolMowing Prevention Prescribed fire Integrated Weed Management

5.  Control strategies that include a combination of methods to reduce weed populations to an acceptable level  Replace one big hammer with “many little hammers” (Liebman and Gallandt 1997)

6. Traditional Management Weed Life Cycle Biocontrol Revegetation Tilling/disking Mowing Herbicides Grazing Fire Hand-pulling Fertilization Prevention Irrigation

7. Future Management Weed Life Cycle Biocontrol Revegetation Tilling/disking Mowing Herbicides Grazing Fire Hand-pulling Fertilization Prevention Irrigation Plant Community Dynamics Desired Vegetation

8. Site Availability Species Performance Species Availability Plant Community Undesired State Plant Community Desired State Framework for IWM

9. Managing Plant Communities

10. Controlling Site Availability

11. Controlling Species Availability

12. Controlling Species Performance

13. Controlled Site Availability Controlled Species Performance Controlled Species Availability Plant Community Undesired State Plant Community Desired State Biocontrol Revegetation Tilling/disking Mowing Herbicides Grazing Fire Hand-pulling Fertilization Prevention Irrigation

14. Healthy Plant Communities

15. Healthy Plant Community = Diverse  Diversity  Multiple species  Multiple functional groups  Utilizes plant resources (water, nutrients, light) through space and time

16. Functional Groups 1.Occupy similar niche 2.Use resources similarly (temporal and spatial) 3.Similar growth forms 4.Similar life histories 5.Similar morphology/root structure

17. What functional groups do you see?

18. Functional groups influence spotted knapweed invasion (Pokorny et al. 2005)

19. Diversity in Your Pasture  Management objective: Grass production Variety of species that mature at different times of the season Different growth habits (bunch vs. sod-forming) bluebunch wheatgrass western wheatgrass Sandberg’s bluegrass

20. Healthy Plant Community = Productive

21. Productive Functional Group Limits Invasion of Annual Grass (James et al. 2008)

22. Healthy Plant Community = Diverse and Productive +...and meets management objectives

23. Plant Biology 101 CO 2 CO 2 + H 2 O + photons (energy) C 6 H 12 O 6 (glucose) + O 2

24. Defoliation

25. Repeated Defoliation

26. Best Management Practices Site Availability  Limit intensity and frequency of disturbance  Weeds like disturbed areas! Do not overgraze Vary grazing rotations Minimize activities that disturb the soil Monitor disturbed areas Killing weed may open up site for re-invasion Consider species availability and species performance

27. Best Management Practices Species Availability  Prevent weeds from producing seed  Prevent weed seed dispersal Driving through infestations Livestock Weed-free seed and forage  If less than 20-30% cover of desirable species, revegetation is likely necessary Diverse and productive seed mixes Easily established Bridge species

28. Best Management Practices Species Performance  Target weed while promoting desirable vegetation Like species repel like species High productivity reduces invasion ?=?=

29. Best Management Practices Species Performance  Use appropriate control method at appropriate time, especially herbicides Limit non-target effects Maximize efficacy Spot-treat

30. Best Management Practices Species Performance  Limit resource availability Fertilization typically not necessary 0.6 ± 0.13 ppm NO 3 -N ≤ 0.05 ppm NO 3 -N Spotted knapweed Bluebunch wheatgrass (Krueger-Mangold et al. 2006)

31. Integrated Management of Cheatgrass

32. Cheatgrass (Bromus tectorum)  Annual  Large and open panicle  Drooping  ½ inch awns  Turns reddish-purple, then brown

33. Winter Annual  Germinates/emerges in fall  Seedlings resume growth in early spring  Produces seed May-June  Plant dies, seed dormant until fall  Seeds remain viable 2-3 years

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

35. Control MethodEffectiveness Prevention Chemical Grazing Revegetation Mechanical Biocontrol Prescribed Fire

36. Prevention  Locate and manage small infestations  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

37. 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, early post- emergence and prior to planting desirable species Imazapic Plateau 2 to 12 ouncesLate summer to early fall, early post- 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 (3-6 months after) Rimsulfuron Matrix 2 to 4 ouncesSpring or fall application followed by planting desirable species in fall (7 months after)

38. Controlling Cheatgrass Performance 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

39. Sprayed on May 11, 2009 Non-sprayed control Number of plants/0.1m 2 Data pooled across 3 sites

40. 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!

41. 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

42. Revegetation Species for SW Montana NativeIntroduced Slender wheatgrassRussian wildrye Thickspike wheatgrassPubescent wheatgrass Streambank wheatgrassSheep fescue Bottlebrush squirreltailPerennial ryegrass Sandberg bluegrassTall wheatgrass Big bluegrassCrested wheatgrass

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

44. 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

45. Prescribed Fire  Cheatgrass may increase with fire if not integrated with other methods  Hot fire will destroy seeds Seeds buried in the soil will be protected  Fire can reduce litter accumulation  Follow-up with grazing, herbicide application, and/or revegetation

46. 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!

47. Thank you! Questions...