Globally herbicide resistance to the Group 3 herbicide mode of action has been confirmed and documented in more than 10 grass and broadleaf weed species across more than 8 countries.
Group 3 resistance exists in Australia in 3 weed species including 5,000 populations of annual ryegrass and dense flowered fumitory. Resistance has generally occurred after 10 -15 years of use of Group 3 herbicides.
Where possible, avoid the use of Group 3 herbicides on dense ryegrass populations. Consider using alternative methods of weed control to reduce weed numbers before applying herbicides.
To assist in delaying the onset of Group 3 resistance, rotate and/or tank mix with herbicides from other modes of action.
Use Group 3 herbicides at robust rates e.g. the maximum label rates to ensure high levels of weed control particularly when targeting annual ryegrass.
The above recommendations should be incorporated into an Integrated Weed Management (IWM) program. In all cases try to ensure surviving weeds from any treatment do not set and shed viable seed. Keep to integrated strategies mentioned in this brochure including cultural weed control techniques to reduce the weed seedbank. Make sure you mix and rotate herbicides from different mode of action groups. Always consult the product label prior to use.
|GROUP 3||Inhibition of microtubule assembly|
|Benzamides:||propyzamide (Effigy®*, Kerb®)|
|Benzoic acids:||chlorthal (Dacthal®, Prothal®*)|
|Dinitroanilines (DNAs):||oryzalin (Rout®*, Surflan®), pendimethalin (Freehand®*, OH2 Ornamental Herbicide®, Stomp®), prodiamine (Barricade®), trifluralin (Bolta Duo®*, Jetti Duo®, Treflan®)|
* This product contains more than one active constituent
List of chemical families, approved active constituents and, in parenthesis, the trade name of the first registered product or successor. Refer to the APVMA website (www.apvma.gov.au) to obtain a complete list of registered products from the PUBCRIS database.
Content last updated: July 14, 2023