Authors - Kim Goodwin, Project Specialist Roger Sheley, Associate Professor Janet Clark, Director, Center for Invasive Plant Management DepartmentEditor - James E. Knight, Extension Agriculture and Natural Resources Program Montana State University

Rangeland Weed Management

Part 2

This is the second half of the weeds PowerPoint presentation

Integrated Weed Management

Develop & maintain healthy, desired plant communities

Variety of preventive strategies

Large versus small weed infestations

Prevention & early detection

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

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 Monitoring is crucial Develop a Monitoring

plan Spring Summer Early Fall

Eradicating small seed patches

Newly established Small than 100 square feet

Prioritize: low-density responds more quickly Document changes in patch size & density Flag or mark

Frequent follow-up

Managing Large Infestations

Limit seed dispersal Requires use of many

management methods Mechanical Chemical Cultural, and Biological

Large Infestations, cont.

Mowing effectiveness based upon:Time of growing seasonBiological characteristics of the target weed

Large Infestations, cont.

Chemical control - herbicidesEradicateReduce weed vigor

Long-term control – when healthy plant community is present

Selecting the right herbicide The target weed Weed density Herbicide toxicity Herbicide degradation time Desired vegetation cover Soil attributes Proximity to water, and Environmental conditions.

Time herbicide application

Nonresidual herbicides: During seeding/rosette, Early bud, and Fall regrowth

Soil-residual herbicides: Timing is less important

Suggested Placement

Depends upon the size of the infestationModerate size – wide treatmentLarge size – perimeter treatment

Cultural Control

Promote growth & competitiveness of desired plants Re-vegetation Management of desired

plants Grazing Management

“Single-entry” Revegetation

One late-fall field entryCost-effectiveYields reliable revegetation

Cultural Control

Grazing Domestic sheep Early bud stage of the weed

Weaken the weeds Over time – effects underground reserves

Eventually reducing stem densities

Biological Control

Insect biocontrols Remove viable fluids Defoliate Eat seeds Bore into roots, shoots, and stems

Effective when integrated with other management strategies

Monitoring & evaluation

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?

Fall-dormant broadcast reseeding effort