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.
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).
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.
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 cultural weed control methods to reduce the weed seedbank. Make sure you mix and rotate herbicides from different mode of action groups. Always consult the product label prior to use.
|GROUP G||Inhibitors of protoporphyrinogen oxidase (PPOs)|
|Diphenylethers:||acifluorfen (Blazer®), oxyfluorfen (Goal®, Rout®, Yates Pathweeder®)|
|N-phenylphthalimides:||flumioxazin (Valor®, Terrain®)|
|Oxadiazoles:||oxadiargyl (Raft®), oxadiazon (Ronstar®)|
|Phenylpyrazole:||pyraflufen (Condor*®, Ecopar®, Pyresta®*)|
|Pyrimidindiones:||butafenacil (B-Power®*, Logran® B-Power®*, Resolva®*), saflufenacil (Sharpen®, Tirexor*®), trifludimoxazin (Tirexor*®)|
|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.
Content last updated: June 10, 2020