Creeping knapweed control

Page last updated: Monday, 16 January 2017 - 4:23pm

Please note: This content may be out of date and is currently under review.

Control methods for creeping knapweed (Rhaponticum repens) a declared pest in Western Australia. Report the presence of this organism before undertaking a control measure.

Report the presence of this pest before undertaking control

Information about this pest can be found on the creeping knapweed: declared pest page.

Chemical requirements

When using any agricultural chemicals please ensure that you always follow instructions on the label and any permit. Users of agricultural chemical products must always strictly comply with the directions on the label and the conditions of any permit. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website.

Control options

Chemical control options can be found below. For other methods of control please refer to the creeping knapweed: what you should know page.

Chemical control options

Recommended herbicides	Clopyralid; Amitrole; Picloram + 2,4-D

Herbicide: Clopyralid (Group I) (various trade names: see APVMA link)
Active ingredient	300g clopyralid as the tri-isopropanolamine salt Also a 750g/kg formulation available
Rate of product/ha	4L/ha
Time of application	September – April on actively growing plants
Wetting agent	Add at recommended rate as per label
Remarks and more information	If plants are small lightly graze the area first to reduce pasture and expose the weed. Allow about seven days for the weed to recover before spraying. Thorough coverage is essential — apply in a volume of not less than 200L of water/ha. This treatment will affect the regeneration of legumes for at least 12 months. Spot spraying is also recommended at 500mL/100L of water, also with the addition of a wetting agent.

Herbicide: Clopyralid (Group I) (various trade names: see APVMA link)
Active ingredient	750g/kg clopyralid potassium salt
Rate of product/ha	1.6kg
Time of application	September – April on actively growing plants
Wetting agent	Add at recommended rate as per label
Remarks and other control measures	If plants are small lightly graze the area first to reduce pasture and expose the weed. Allow about seven days for the weed to recover before spraying. This treatment will affect the regeneration of legumes for at least 12 months. Thorough coverage is essential; apply in a volume of not less than 200L of water/ha. Spot spraying is also recommended at 20g/10L of water, also with the addition of a wetting agent.

Herbicide: Amitrole T, Weedeath (Group F)
Active ingredient	250g/L amitrole + 220g/L ammonium thiocyanate
Rate of product	1.1L/100L water
Wetting agent	Add recommended product @ 55mL/15L water for knapsack spraying
Time of application	When plants are actively growing, just prior to flowering
Remarks	Respraying will be necessary

Herbicide: Picloram (Group I) (various trade names: see APVMA link)
Active ingredient	300g/L 2,4-D and 75g/L picloram present as tri isopropanolamine salts
Rate of product/ha	7.5L
Time of application	During late spring to summer
Remarks and other control measures	This treatment will affect the regeneration of legumes for at least 12 months. Also spot spraying treatment of 2L/100L water.

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Contact information

Pest and Disease Information Service (PaDIS)

+61 (0)8 9368 3080

Email Pest and Disease Information Service (PaDIS)

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Creeping knapweed control

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