Use canola to smash grass weed burden

Farmers urged to lower grass weed seed bank during canola phase


Not only are canola prices at very attractive levels, researchers say the crop can play a pivotal role in lowering weed seed numbers.

Chris Preston, University of Adelaide researcher, says growers can target ryegrass burdens in their canola phase.

Chris Preston, University of Adelaide researcher, says growers can target ryegrass burdens in their canola phase.

RESPECTED weed researcher Chris Preston is urging growers with wheat-canola rotations to target their canola phase as a chance to bring down the grass weed burden.

Speaking at last week’s Southern Farming Systems (SFS) Agri-Focus event in southern Victoria, where wheat-canola is the dominant rotation, Dr Preston, a researcher at the University of Adelaide, said the herbicide options within the canola rotation were much greater than in the wheat phase.

“We really want to protect the effective chemistries we have got in wheat, such as the Group K chemistry found in Bayer’s Sakura product,” Dr Preston said.

“The thinking needs to be, while in the wheat phase try and keep a lid on weed numbers, don’t let it get any worse and then when you go into canola that is where you make serious inroads into the weed numbers as there are more options out there.

“You also have the advantage in canola of being able to more effectively control those later season germinations of ryegrass, whereas options can be quite limited on this front in wheat.”

Dr Preston said there was emerging resistance in ryegrass to Group J herbicides, such as Avadex, putting further pressure on herbicide options in the wheat phase.

In terms of emerging options, he said FMC’s new Altiplano product, for use in canola, was promising, but added as it contained Group K chemistry farmers needed to be careful if they planned to use Sakura the following year.

“The good news is that Altiplano also contains Group Q chemistry which is nice from a resistance minimization point of view, but you need to go through your rotation carefully and see if you are leaning too heavily on the Ks.”

Dr Preston said farmers also needed to look at non-chemical methods of control.

“Things like windrow burning, chaff carts, heavy sowing rates to outcompete the weeds, all those means of getting the weed seed bank down are useful tools to lessen the need for herbicides.”


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