6 Aug 2024. Paul McIntosh, Pulse Australia and WeedSmart
There was a solid turnout of growers and agronomists at last week’s GRDC one day update in Pittsworth.
A long-term agronomist colleague and friend of mine, Garry Onus from Nutrient in Moree, highlighted the scourge of the Australian Cropping Weeds scene of Annual Ryegrass (or Rigid Ryegrass to some). Used originally in the early 1900’s as livestock fodder, this plant is now well out of place in our farming systems. In other words, it is classed as a weed, with some peculiarities like being a known out-crosser and have allelopathic effects on other plants around itself. By being an out-crosser, it basically makes the species tougher, stronger and very adaptive to growing conditions, and unfortunately for grain growing operations, very prone to developing herbicide resistance.
So, we have inherited Annual Ryegrass (ARG) seed by hay bales transported from the south, cereal grain in times of severe drought up here, mechanical machines like harvesters and even just vehicles passing through, this plant we now call a weed and a very difficult to control weed at that.
Garry outlined some residual herbicides like Pyroxasulfone and Triasulfuron used in wheat crops in Northern NSW and showed first-hand the good results they gave in stopping Annual Ryegrass or ARG in its tracks from germinating.
In decades gone passed when we have a weed problem, we have simply rotated our cropping systems to a summer crop and used other herbicides like atrazine and prometryne to vacuum up these pesky weeds from germinating and this is still a good option.
From my local experiences here in Southern Queensland, Glyphosate just bounces off ARG plants. In other technical words it is very ineffective due to the high folds resistance levels to various Modes of Action or MOA, like Glyphosate (Group 9) and the Fops and Dims in the Group 1 class MOA.
My own take home messages are firstly, to be able to identify this shinny leaf grass plant in its early stages preferable before any crop sowing programme, use as many weed control options as you can and I am referring to the Weedsmart BIG 6 tips and Tactics here and use an Area Wide Management process to clean up errant ARG plants before they set seed on fence lines, table drains and in future cropping paddocks including spring/summer ones.
That’s all folks.
Have had a big week in South Australia at a well-attended WeedSmart week on Eyre Peninsula, plus yesterday’s Pittsworth gig and then off to the Australian Cotton Conference this coming week 6-8 August. A huge August month of away work for me with a weeklong trip to NSW and then flying to the Burdekin region for herbicide resistance talks the week after. Phew.
PS. Some motels have the trickiest TV sets to work (: (:
Image: Ryegrass.