Specific guidelines for Group A herbicides

GROUP A HERBICIDE

High resistance risk

Globally herbicide resistance to Group A herbicides has been confirmed and documented in more than 40 grass weed species across more than 40 countries. Group A resistance is extensive and prolific with tens of millions of hectares affected, in fact it is the second most likely herbicide mode of action to develop resistance with only the Group B mode of action more likely.

Group A resistance commonly exists across wide areas of Australia in the grass weed species including more than 20,000 populations ofannual ryegrass, annual veld grass, more than 5,000 populations ofwild oats, phalaris, more than 200 populations of brome grass, crabgrass, crowsfoot grass and more than 200 populations of barley grass. Resistance has developed in broadacre and vegetable situations.

Research has shown that as few as 6 applications to the same population of annual ryegrass can result in the selection of resistant individuals. A population can go from a small area of resistant individuals to a whole paddock failure in one season.

  1. Fops, dims and dens are Group A herbicides and carry the same high resistance risk.
  2. Where a Group A herbicide has been used on a particular paddock for control of any grass weed, avoid using a Group A herbicide to control the same grass weed in the following season, irrespective of the performance it gave.
  3. Frequent application of Group A herbicides to dense weed populations is the worst case scenario for rapidly selecting for resistance.
  4. Where resistance to a member of Group A is suspected or known to exist, there is a strong possibility of cross resistance to other Group A herbicides. Therefore use other control methods and herbicides of other mode of action groups in a future integrated approach.

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

CHEMICAL FAMILYACTIVE CONSTITUENT (FIRST REGISTERED TRADE NAME)
GROUP A Inhibitors of acetyl co-enzyme A carboxylase (Inhibitors of fat synthesis/ACC’ase inhibitors)
Aryloxyphenoxypropionates:
(Fops):


clodinafop (Topik®), cyhalofop (Barnstorm®), diclofop (Cheetah® Gold*, Decision®*, Hoegrass®), fenoxaprop (Cheetah® Gold* , Wildcat®), fluazifop (Fusilade®, Fusion®*), haloxyfop (Verdict®), propaquizafop (Shogun®), quizalofop (Targa®)
Cyclohexanediones:
(Dims):

butroxydim (Falcon®, Fusion®*), clethodim (Select®), profoxydim (Aura®), sethoxydim (Cheetah® Gold*, Decision®*), tralkoxydim (Achieve®)
Phenylpyrazoles:
(Dens):

pinoxaden (Axial®)

* 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. 


URL: https://croplife.org.au/resources/programs/resistance-management/2018-specific-guidelines-for-group-a-herbicides-2/
Content last updated: June 22, 2018

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

The information given in this strategy is provided in good faith and without any liability for loss or damage suffered as a result of its application and use. Advice given in this strategy is valid as at 22 June 2018. All previous versions of this strategy are now invalid.