Group G Herbicide Comparison
Group G herbicides when added to knockdown herbicides, generally don’t improve the final weed control results, rather they increase the speed of desiccation.
With the exception of Sharpen, Group G products are contact, non-systemic herbicides which can be added to Glyphosate or other knockdown herbicides, prior to sowing winter crops and pastures. These products disrupt the photosynthetic pathway, leading to membrane breakdown and rapid desiccation. As a result, they provide rapid brown-out of target weeds.
One exception is the control of marshmallow which appears to be superior with the addition of a Group G spike.
Sharpen does have some systemic activity and as such, has registrations as a herbicide in its own right, rather than just being a spike with knockdown herbicides.
The table below shows the available Group G herbicides and their key attributes. Specific comments are provided below:
When targeting marshmallow, Hammer at 15-20 ml/ha is the most reliable additive to knockdowns. The cost of this addition is between $3.60 and $4.80 /ha. This spike is roughly equivalent to an additional litre of Glyphosate, so it is only recommended when marshmallow is a significant weed in the paddock.
Goal or other generic Oxyfluorfen products are the cheapest option. They are generally effective in increasing the speed of brown-out, but may not be as reliable as Hammer 400 on marshmallow. Goal may also be of benefit by increasing the speed of desiccation of weeds prior to burning stubbles.
Sharpen is not priced as a knockdown spike, although it can be mixed with Glyphosate to provide good control of marshmallow, sow thistle, young fleabane, radish and volunteer Roundup Ready Canola, amongst other weeds. Sharpen is more likely to be used as a mix partner on weeds that are either resistant to, or tolerant of Glyphosate, or where a phenoxy herbicide cannot be used. Hence it is priced at a premium level.
Logran B Power is Logran 750 WG with the addition of a Group G spike. It is very expensive and in most cases there is a more cost effective option that will achieve the same result.
Valor 500 and Logran B Power cannot be used before sowing Canola due to plant-back restrictions. Logran B-Power has at least 12 months plant-back restriction for sowing Canola and pulse crops. This period increases on soils with pH (CaCl2) greater than 6.5.