Spotted Knapweed/Control Measures- LCCD has compiled a Chemical Handbook to assist producers with noxious weed treatments

Control Measures for Spotted Knapweed
Alias:  Centaurea maculosa
 
Mechanical Control:
  • Cultivation to 7 inches will help reduce Spotted Knapweed and encourage grass growth.  Persistent hand pulling can control small infestations.  The entire plants must be removed.
 
Cultural Control:
  • Repeated grazing by sheep and goats when grasses are dormant reduces seedlings and rosettes.
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    Chemical Control:
    • Tordon
        Rate:       1 lb. acid equivalent per acre.

        Time:       Apply in spring at rosette stage prior to bolting.
        Remarks: Selective treatment at the suggested rate will not damage perennial grasses.
        Caution:   Restricted use pesticide.  Must be applied by or supervised by a Certified Applicator.  Follow label recommendations                     and precautions.  Do not contaminate water.
     
  • Roundup
       Rate:         3 lbs. acid equivalent per acre.
       Time:        Apply in spring – rosette to bud stage.
       Remarks:  Roundup also kills grass that might compete with new seedlings. After treatment, seed with a locally adapted grass.
       Caution:    Follow label recommendations and precautions.  Do not contaminate water.
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    Rates for 3-4 Gallon Back Pack Sprayer/Tordon or Roundup:
    • Add 6-8 ounces of herbicide to 3-4 gallons of water in the sprayer.  *Add a couple ounces of Surfactant and stir.  *NOTE:  Be sure always to follow label rates as percent of active ingredients may vary.

    Cooperatively prepared by the Lander County Conservation District and the Nevada Department of Agriculture.

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