Spotted knapweed (Centaurea stoebe) is a short-lived perennial or biennial that spreads by seed and invades disturbed soils, pastures, and rangeland.

It reduces forage quality and displaces native vegetation.

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Management Strategies

Chemical Control (Most Effective)

• Timing:
  • Rosette stage (spring or fall)
  • Early bolting stage
• Recommended Active Ingredients:
  • Aminopyralid (Milestone)
  • Clopyralid
  • Picloram (Tordon)
  • 2,4-D (less consistent)

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Mechanical Methods

• Hand Pulling:
  Effective for small infestations if entire root is removed.
• Mowing:
  Must be timed before seed production; limited effectiveness.

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Cultural & Preventative Measures

• Maintain dense grass cover
• Minimize disturbance
• Reseed bare ground quickly

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Biological Control

• Although, biologicals are available the affects are limited
• Several established agents, including:
  • Seedhead weevils
  • Root borers

These can significantly reduce long-term populations.

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Key Timing Reminder

Focus on rosettes before bolting or seed set.

Need Assistance?

For more information or help with weed management:

• Contact: Kevin
• Phone: (970) 799-2473
• Email: kevin@mallowlandandpest.com