Marketing manager Fenton Hazelwood says a new herbicide which has been available to growers in the USA for the past few seasons, and contains the novel active ingredient topramezone, has been submitted for registration in NZ and it promises a platform for gaining the upper hand on many invasive grass and broadleaf species.
The new herbicide is applied as a post-emergence and has a wide window of application which allows for better timing of the spray to gain control of those later germinating grass and broad leaf weeds.
According to AgResearch weed scientist Trevor James, in soils with a long history of maize production the weed spectrum is changing towards more difficult to control weeds due to changes in soil biology, Hazelwood says.
Many annual grass weeds germinate throughout the summer as temperature and moisture thresholds are attained, and this
staggered emergence can be a serious problem as the residual activity of the pre-emerge herbicide used also diminishes with time.
“A later application which will be achievable with topramezone can target a greater number of weeds before canopy closure and thus remove both the weed and the source of the seed.
“As we progress closer to the season there will be more information available on this new product for growers, contractors and field advisors,” Hazelwood says.
Meantime, last season’s launch of Sharpen was well received by maize growers.
BASF territory manager John Haliday says firstly it was applied early in the season for burn down as a tank mix product with glyphosate to address difficult weeds such as established docks and creeping buttercup.
“Sharpen plus glyphosate with Hasten adjuvant provided that very quick brown out and weed desiccation which made cultivation so much easier.”
Following planting, Sharpen was combined with acetochlor as a broad spectrum tank mix to provide better control of many annual weeds that germinate during the establishment phase of the crop.
John Haliday says as a soil residual Sharpen provided weed control up to and beyond the labeled expectations and proved particularly useful in keeping fathen and other annual broad leafs from competing with the maize.
“Sharpen is set to become a great addition to the residual herbicide toolbox for growers as they evaluate its potential on their own farms.
“This season the label is to be expanded to cover use of Sharpen in both maize and sweetcorn crops,” he adds