Moderate resistance risk

Resistance to Group K herbicides is possible in Australia and may develop in broadacre or horticulture situations particularly in annual ryegrass.

Where possible, avoid the use of Group K herbicides on dense 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.

All the above recommendations should be read in conjunction with the Integrated Weed Management (IWM) strategies

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 (Devrinol®)
Chloroacetamides: dimethenamid (Frontier®-P, Outlook ®), 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. 


CropLife Australia’s Resistance Management Strategies provide a guide for crop protection product rotation through product groups.  The strategies are a useful tool that supports farmers’ adoption of resistance management.

All crop protection products must be handled and applied strictly as specified on the product label or APVMA permits.  These Resistance Management Strategies do not replace product labels.  They are a guide only and do not endorse particular products, groups of products or cultural methods in terms of their performance.  It is important to check with the Australian regulator’s (APVMA) product database for contemporary information on products and active constituents.  The database can be sourced through www.apvma.gov.au