Australia
May 28, 2015
When Airbus delivered the first A380 aircraft in 2008 they were very proud of the fact that it was the quietest commercial airliner ever produced.
The unintended consequence of this, however, was that it led to a worse experience for passengers as more unpleasant noises (e.g. crying babies, snoring passengers, flushing toilets) were elevated in the quieter cabin. Back to the drawing board! They actually engineered some sound back into the cabin by piping in ambient noise.
When ConsultAg agronomist Garren Knell tackled a high ryegrass seedbank with one of his clients in southwest Western Australia 12 years ago, they opted to introduce legume based pasture and triazine tolerant canola into the rotation. They took an aggressive approach to managing the ryegrass seedbank and it payed off.
The unintended consequence, was one of Australia’s first populations of simazine resistant silver grass.
Garren sampled some silver grass in 2014 and Dr Mike Ashworth (former AHRI researcher) confirmed that it was highly resistant to simazine. The population was in fact more than 594 fold resistant. Genetic testing revealed that the mechanism for resistance was a common one that often gives high level resistance.
The rotation Garren’s client adopted resulted in 8 applications of triazine in 12 years. The ryegrass received double knocks in the form of grazing, spray topping and clethodim. The silver grass avoided these second knocks, and on reflection, the triazine herbicides were the only tool used in 8 of the 12 years for silver grass control.
This goes to show that when our eye is on the world champion of resistance, annual ryegrass, it is pretty easy to inadvertently evolve resistance in another weed. So what other herbicides are still available for this population?
Topics
Species
