Rangeland Weed Management
Authors - Kim Goodwin, Project Specialist
Roger Sheley, Associate Professor
Janet Clark, Director, Center for Invasive
Plant Management Department
Editor - James E. Knight, Extension
Agriculture and Natural Resources
Program Montana State University
Part 2
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This is the second half of the weeds
PowerPoint presentation
Integrated Weed Management
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Develop & maintain healthy,
desired plant communities
Variety of preventive strategies
Large versus small weed
infestations
Prevention & early detection
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Prevention – most
effective, least costly
 Limit
weed dispersal
 Detect and eradicate
early
 Re-vegetate when
necessary
 Properly manage
desired plants
Limiting dispersal of weed seeds
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Certified weed-free gravel, seed
mixes, forage, and mulch
Clean undercarriage of vehicles
Boots and clothing
Livestock movement
Detect early – pull, clip, bag,
burn
Eradicate
Detecting & Eradicating Weed
Introductions Early on
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Monitoring is crucial
Develop a Monitoring
plan
 Spring
 Summer
 Early
Fall
Eradicating small seed patches
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Newly established
Small than 100 square feet
 Prioritize:
low-density responds more quickly
 Document changes in patch size & density
 Flag or mark
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Frequent follow-up
Managing Large Infestations
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Limit seed dispersal
Requires use of many
management
methods
 Mechanical
 Chemical
 Cultural,
and
 Biological
Large Infestations, cont.
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Mowing effectiveness based upon:
 Time
of growing season
 Biological characteristics of the target weed
Large Infestations, cont.
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Chemical control - herbicides
 Eradicate
 Reduce
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weed vigor
Long-term control – when healthy plant
community is present
Selecting the right herbicide
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The target weed
Weed density
Herbicide toxicity
Herbicide degradation time
Desired vegetation cover
Soil attributes
Proximity to water, and
Environmental conditions.
Time herbicide application
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Nonresidual herbicides:
 During
seeding/rosette,
 Early bud, and
 Fall regrowth
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Soil-residual herbicides:
 Timing
is less important
Suggested Placement
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Depends upon the size of the infestation
size – wide treatment
 Large size – perimeter treatment
 Moderate
Cultural Control
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Promote growth & competitiveness of
desired plants
 Re-vegetation
 Management
of desired
plants
 Grazing Management
“Single-entry” Revegetation
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One late-fall field entry
 Cost-effective
 Yields
reliable revegetation
Cultural Control
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Grazing
 Domestic
sheep
 Early bud stage of the weed
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Weaken the weeds
 Over
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time – effects underground reserves
Eventually reducing stem densities
Biological Control
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Insect biocontrols
 Remove
viable fluids
 Defoliate
 Eat
seeds
 Bore into roots, shoots, and stems
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Effective when integrated with other
management strategies
Monitoring & evaluation
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Periodic observation is necessary
Does not need to be elaborate
 Photo
monitoring
Integrated Weed Management Plan
Following a burn – weeds are likely
 Is revegetation necessary?
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 Fall-dormant
broadcast reseeding effort