Specific guidelines for Group G herbicides

Moderate resistance risk

Group G herbicides are inhibitors of the protoporphyringen oxidase (PPO) enzyme. There are currently no known populations of weeds resistant to Group G in Australia. However, there are 6 weeds with confirmed resistance to Group G herbicides elsewhere in the world and in particular in populations of Amaranthus spp. in the USA.

The increased use of Group G herbicides as stand-alone herbicides in Australia is likely to increase the risk of resistant populations developing. The use of Group G herbicides in co-formulations or as tank mixtures in-crop or on fallows has a lower risk of resistant populations developing.

Tank mixtures and co-formulations

Most current recommendations for Group G herbicides are for mixtures with another herbicide, e.g. carfentrazone plus glyphosate, pyraflufen plus MCPA amine. There are also some co-formulations that incorporate at least two modes of action e.g. Aptitude® (carfentrazone + metribuzin) and Pyresta® (pyraflufen + 2,4-D).

  • Mixtures should be applied at full label rates to provide robust weed control
  • Rotation of all herbicide modes of action should be employed between seasons

Stand-alone applications

The risk for Group G herbicide resistance is highest where they are used alone, e.g. flumioxazin in cotton or oxyfluorfen as a residual herbicide.

  • If there are significant escapes following the application of a Group G herbicide, consider using another herbicide with a different mode of action or a non-herbicide control method to stop seed set. If not possible, be sure to include a different mode of action in the next herbicide application.

The above recommendations should be incorporated into an Integrated Weed Management (IWM) program. In all cases try to endure 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 FAMILYACTIVE CONSTITUENT (FIRST REGISTERED TRADE NAME)
GROUP G Inhibitors of protoporphyrinogen oxidase (PPOs)
Diphenylethers:


aciflurofen (Blazer®), oxyfluorfen (Firestorm®*, Goal®, Rout®*, Yates Pathweeder®*)
N-phenylphthalimides:
flumioxazin (Valour®, Terrain®)
Oxadiazoles:
oxadiargyl® (Raft), oxadiazon (Ronstar®)
Phenylpyrazole:
pyraflufen (Ecopar®, Pyresta®*)
Pyrimidindiones:
butafenacil (B-Power®, Logran® B-Power®*, Resolva®*), saflufenacil (Sharpen®)
Triazolinones:
carfentrazone (Affinity®, Aptitude®*, Broadway®*, Buffalo Pro Weedkiller®*, Silverado®*)

* 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/specific-guidelines-for-group-g-herbicides/
Content last updated: June 28, 2019

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 27 June 2019. All previous versions of this strategy are now invalid.