Report the presence of this pest before undertaking control
Information about this pest can be found on the perennial thistle: declared pest page.
Login or set up a new account on DAFWAs online training site to access:
- a training course on how to identify perennial thistle and report it.
- training material that you can use to teach community groups how to identify perennial thistle.
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 declared plant control handbook.
Chemical control options
| Recommended herbicides | Rosette to flowering:Picloram + 2,4 D amine Actively growing:Glyphosate |
|---|
| Herbicide: Picloram + 2,4 D amine (Group I) | |
|---|---|
| Active ingredient | 75g/L picloram + 300g/L of 2,4-D |
| Rates of dilution for spot spraying | 1:150 |
| Amount of product/10L water | 65mL |
| Rate of product/ha | Not recommended |
| Time of application | Winter-spring rosette to flowering stage. Optimum stage is during budding. |
| Remarks | Re-treatment may be necessary as surviving rootstocks will reshoot. |
| More information and other control methods | Grubbing and cultivation ineffective due to ability to reshoot from rootstock and root fragments. Treatment is residual and will control most broadleaved plants for one or two growing seasons. Triclopyr + picloram formulation would probably do the same control. |
| Herbicide: Clopyralid (Group I) (various trade names: see APVMA link) | |
|---|---|
| Active ingredient | 300mL/L and 750g/kg clopyralid |
| Rate of product use |
|
| Remarks | Seedlings – just prior to flowering |
| Further information | Rates of liquid clopyralid appear to be too low so the 750g formulation preferred. |
| Herbicide: Glyphosate (Group M) (various trade names: see APVMA link) | |
|---|---|
| Active ingredient | 360, 450, 490, 500 and 540g/L and 680g/kg glyphosate |
| Rates of dilution for spot spraying | 1:100 for 360g/L |
| Amount of product/10L water |
|
| Rate of product per hectare | Not recommended |
| Time of application | Actively growing at flowering |
| Remarks | Avoid cultivation prior to treatment. Re-treatment may be necessary. |
| More information and other control methods | In wet areas use only approved glyphosates such as Roundup® Biactive and Razor®. |