Moderate resistance risk
Globally herbicide resistance to the Group K herbicide mode of action has been confirmed and documented in 5 weed species across 7 countries.
Resistance to Group K herbicides in Australia has developed in more than 20 populations of annual ryegrass. Further development of resistance in the near future is likely given the reliance on Group K herbicide chemistry for weed control across large areas of Australia.
Where possible, avoid the use of Group K herbicides on dense annual ryegrass populations. Consider using alternative methods of weed control to reduce weed numbers before applying herbicides.
Use Group K herbicides at robust rates eg the maximum label rates to ensure high levels of weed control particularly when targeting annual ryegrass.
To assist in delaying the onset of resistance, rotate Group K herbicides with herbicides from other modes of action.
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 rotation of mode of action groups. Make sure you rotate between products from different mode of action groups. Always consult the product label prior to use.
CHEMICAL FAMILY ACTIVE CONSTITUENT (FIRST REGISTERED TRADE NAME)
GROUP K Inhibitors of cell division / Inhibitors of very long chain fatty acids (VLCFA inhibitors)
Acetamides: napropamide (Altiplano®*, Devrinol®)
Chloroacetamides: dimethenamid (Frontier®-P, Outlook ®), metazachlor (Butisan®), metolachlor (Boxer® Gold*, Dual® Gold, Primextra® Gold*), propachlor (Prothal®*, Ramrod®)
Isoxazoline: pyroxasulfone (Sakura®)
* 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: June 28, 2019