Katamatite grower Jarrod Lukies and James Murray, agronomist with IK Caldwell at Cobram, sampling canola quality prior to last harvest on the Lukies’ ‘Lanivet Farms’ property.
Herbicide-resistant annual rye-grass and wild oats are proving a challenge for many croppers in north-east Victoria, however those following the industry mantra to mix and rotate herbicides are winning the battle.
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Of course, the strategy is helped when effective new herbicides are introduced, which recently occurred for controlling the grasses in the canola phase of cropping programs.
James Murray, agronomist with IK Caldwell at Cobram, said rye-grass was particularly resistant to glyphosate and had been a major problem, while some wild oat populations were resistant to FOP herbicides.
He said growers traditionally applied trifluralin and triallate against rye-grass and wild oats in canola and more recently used mixes like propyzamide and trifluralin, however Tenet® herbicide was now providing a new option with strong benefits.
Containing the active ingredient, metazachlor, Tenet is the only Group 15 herbicide that can be applied pre-emergent or post-emergent in canola.
Developed by ADAMA Australia, it has the broadest weed control spectrum, providing residual control or suppression of more than 20 annual grass and broadleaf weeds, also including barley grass, brome grass and capeweed.
James said Tenet washed-off stubbles well and compared with propyzamide, it was far more mobile and highly soluble, which was important considering autumn rains could be limiting through the region.
“That’s what gives it the edge. There’s a lot to like about it. It can be used IBS (incorporated by sowing), but it also has the flexibility that if you haven’t used it upfront and you have some weed escapes, it can be used as an early post-emergent treatment.’’
“As long as it is tank-mixed with something IBS, it provides high level control of annual rye-grass and is quite superior on wild oats. It also has been very good on hogweed, milk thistle and wet weeds, particularly toad rush.
“Usually, we will get third and fourth germinations of rye-grass and Tenet has been important in reducing numbers leading into the next wheat crop.’’
Katamatite grower Jarrod Lukies said herbicide-resistant annual rye-grass and wild oats were becoming more prevalent on the family’s ‘Lanivet Farms’ property and they were strongly targeting them during the canola phase of their cropping program.
The Lukies grow conventional and herbicide-tolerant canola varieties, including for seed production, and they are included in continuous rotations with wheat and barley winter crops, as well as with summer crops of corn.
Jarrod said previously for their canola, they applied trifluralin and triallate pre-emergent herbicides, followed by an in-crop treatment with clethodim and then application of glyphosate later in the season to help prevent grass seedset.
Last year, there was also a shortage of propyzamide and this prompted a re-think for their pre-emergent applications.
They took advantage of an opportunity to “double knock’’ with paraquat, followed by a pre-emergent application of trifluralin and triallate herbicides, and then added the Tenet herbicide to post-emergent applications of clethodim.
“We noticed quite a few escapes post-emergent, so we went with 750 millilitres/hectare of Tenet with the clethodim and we found that it did a really good job of cleaning up those small, in-furrow grasses. It was really quite good and we will adopt it as practice,’’ Jarrod said.
“We are getting some clethodim resistance, so with Tenet, it will clean up the escapes that the clethodim is not getting.
“It also stopped a lot of the wet weeds that otherwise would not have been controlled and the results spoke for themselves — the paddocks were quite clean after the applications.
“Tenet is a new tool and hopefully it will also add to the longevity of some existing chemicals we use.’’
He said they liked the fact it could be applied pre-emergent or post-emergent and it mixed and carried well with other herbicides.
The Lukies applied Tenet via their Patriot sprayer, which features a pulse width modulation spraying system. They generally aim for a medium droplet spectrum.
“It was stable and good to handle in the mix, and there were no effects on the crop,’’ Jarrod said.
He expected Tenet would become “a key tool in the toolbox’’ for their cropping program, whether applied pre-emergent or post-emergent, to help limit weed resistance and also extend the use of other herbicides.
Jarrod Lukies and James Murray inspect the excellent weed control achieved across the full soil profile in a canola paddock last season following the post-emergent application of the specialist canola herbicide, Tenet, in a tank mix with clethodim.
“We will do paddock plans and look to address those issues and apply what is best for our cropping system.’’
James said the industry would be careful to ensure correct stewardship with the new herbicide.
“We want to preserve Group 15s for as long as we can. We want to ensure we don’t break the product,’’ he said.
“Tenet is a product to use strategically. If we have got high (grass weed) numbers, we need to be doing everything we can to reduce those numbers.’’
Jarrod Lukies said he expected Tenet would become “a key tool in the toolbox’’ for their cropping program, whether applied pre-emergent or post-emergent, to help limit weed resistance and also extend the use of other herbicides.
