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Greg Condon, WeedSmart extension agronomist for southern New South Wales, emphasised that heading into the 2022 winter cropping season, growers and agronomists needed to familiarise themselves with how these new herbicides behave in the soil.
Condon said the wet conditions experienced last season gave some useful insights into the new chemistries under commercial field conditions. The new ‘pre-ems' have increased growers' options for mixing and rotating modes of action in cereal and broadleaf crops this winter.
"In central and southern NSW, the 2021 winter cropping season started dry and soon became very wet," Condon said.
"There was a lot for us to learn with five new pre-emergent herbicides either coming to market or in their final pre-release trials.
"Last season, we observed the importance of matching the right herbicide to the soil type and soil moisture levels, and how critical it is to get the seed depth right and the furrow closed to ensure crop safety and effective weed control.
"These herbicides are all well-suited to minimum and no-till systems with significant stubble load. Collectively, they are generally more mobile in the soil and wash off stubble easier than many of the older pre-emergent herbicides. Following the label directions carefully will provide the best protection of the crop from potential damage."
Condon said the new products offer growers increased flexibility in application timing and bring new modes of action for rotational use in cereals and broadleaf crops.
"Having more diversity in any herbicide program will extend the effective ‘life' of all the products used."
Included in the WeedSmart new pre-em list are Overwatch, Mateno Complete, Callisto, Ultro and Reflex.
"Pre-emergent chemistry is a key tactic in an integrated weed management program, and these new releases significantly expand the options for growers to mix and rotate modes of action throughout the crop sequence," Condon said.
For more information about maximising the benefits of new chemistry, visit the WeedSmart website: www.weedsmart.org.au
