Moderate resistance risk
Resistance to the Group H herbicide mode of action is known for a number of populations of Amaranthus species in the United States, which demonstrates the potential for weeds to develop resistance to this mode of action. Continuous usage of Group H herbicides in the United States has resulted in resistance in Amaranthus species in a relatively short time.
There are currently no known weeds resistant to Group H herbicides in Australia however, resistance to this mode of action is inevitable given its continued usage
Synergistic interactions have been documented for several Group H and Group C herbicide combinations. Where possible, apply a Group H herbicide in combination with a Group C herbicide to maximise efficacy. Always use the label rate of herbicide whether or not a single active ingredient (eg. isoxaflutole) or combinations of active ingredients are applied (eg. isoxaflutole + simazine, pyrasulfotole/bromoxynil).
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 H Bleachers: Inhibitors of 4-hydroxyphenyl-pyruvate dioxygenase (HPPDs)
Isoxazoles: isoxaflutole (Balance®, Palmero TX®*)
Pyrazoles: benzofenap (Taipan ®), pyrasulfotole (Precept®*,Velocity®*)
Triketone Bicyclopyrone (Talinor®*)
* 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 22, 2018