At a time when there has never been a greater choice of herbicide technology to fight weeds, resistance in ryegrass in canola is providing an ever-present challenge to farmers to keep on top of.
Fortunately for growers heading along to the Hart Field Day on Tuesday, September 21, Dr Peter Boutsalis from The University of Adelaide's Herbicide Resistance Group and Plant Science Consulting will be on hand to share the latest observations on herbicide resistance.
"I'll be there sharing what we know about the current herbicide resistance levels in ryegrass from GRDC random weed spraying and my private resistance testing," he said.
"There will be information on differences in expression of glyphosate resistance in weeds based on growth stage, how increasing rates can improve control if resistance is at an early level, also, using reputable glyphosate products.
"The session will also cover how mixes with atrazine can be antagonistic, mixes with clethodim that are additive or synergistic, how glyphosate activity is reduced under warm conditions, and how water-stressed plants are less affected.
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"Random weed survey data collected in the past five years across SA and Vic gives us a baseline of the incidence of herbicide resistance, and one of the surprising details identified is that resistance to clethodim is lower than what many growers may expect.
"Atrazine is another important herbicide used to combat ryegrass in canola, and we have found resistance to atrazine in ryegrass is not common, and poor field performance is rarely due to herbicide resistance."
To find out more from Peter, and ask him any specific questions about herbicide resistance, head along to one of his sessions during the rolling Hart Field Day program.
The event gets underway on Tuesday, September 21, with gates open at 9am and an official opening at 10am. The first session starts at 10.30am sharp.
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