Australian Herbicide Resistance Initiative (AHRI)

Why do pre-em herbicides last so long before resistance bites?

Tag Archives | evolution

Gayle Somerville, pre-em

Australian Herbicide Resistance Initiative (AHRI)

Why do pre-em herbicides last so long before resistance bites?

Once in a while, someone comes along and asks a question that you have never given much consideration to. Like, “Why does beer garden beer taste so bad?” or “Why do hotels always give away piles of stuff except for what you actually need, like a toothbrush or a razor?” and “Why do our pre-emergent herbicides last longer than our post-emergent herbicides before resistance bites”? Sure, we had probably considered this question in the past, but many of us would have just assumed that the gene frequency for resistance to our pre-emergent herbicides was low. However, Gayle Somerville, who recently…

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Australian Herbicide Resistance Initiative (AHRI)

Mini-series – ‘Pre-emergent: A tale of four herbicides’ | Season Finale – Episode 4: ‘Redemption’

They said ‘yeah, it happened in the lab but that will never happen in real life’. The evil Busi said ‘I’m not a bad person, I’m not trying to create a monster, I just found something really bad and felt that I should tell you about it’. The naysayers said, ‘sure, just tell us when it happens in real life, then we’ll believe you’. Guess what, it happened! Dun dun duuuun!!!! Canadian researchers Mangin, Hall and Beckie have found wild oats that are resistant to Avadex®, and have never been sprayed with Sakura®, were found to be Sakura® resistant. This…

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Australian Herbicide Resistance Initiative (AHRI)

Mini-series: ‘Pre-emergent: A tale of four herbicides’ – Episode 3: ‘Phorate’

  Previously on ‘Pre-emergent: A tale of four herbicides’… In Episode 1, AHRI researcher Roberto Busi turned to the dark side and evolved Sakura resistance in the lab, and then found this had caused cross-resistance to Boxer® and Avadex®, creating the world’s most wanted criminal ryegrass population. In Episode 2, Busi teamed up with Todd Gaines and Martin Vila-Aiub. They found that the world’s most criminal ryegrass could share its resistance trait by passing on just one single gene. Fortunately, they found that this gene was semi-dominant. Now, in Episode 3, Busi is at it again, trying to correct his…

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Australian Herbicide Resistance Initiative (AHRI)

Mini-series – ‘Pre-emergent: A tale of four herbicides’ | Episode 2: ‘Incomplete dominance’

Many of our Australian readers would remember the great TV mini-series ‘Underbelly’ that exposed the underworld of Melbourne and Sydney. It got the whole country talking about Carl Williams and the Moran brothers, and the corruption in the police force. Similarly, our mini-series on pre-emergent herbicides will seek to reveal the underbelly of the herbicide world. We started this series a couple of years ago and plan to pick it up where we left off. ‘Pre-emergent: A tale of four herbicides’ has the whole of the Australian agricultural industry talking about cross-resistance, P450’s, GST’s, and the sting in the tail…

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Australian Herbicide Resistance Initiative (AHRI)

New boy band – ‘The Feathertop Rhodes’

Feathertop Rhodes (FTR) Grass is the boy band of the weeds world. They pop up quickly from obscurity (first to germinate after rain), stress easily at the first sign of trouble (dry), and can be all done and dusted in 18 months (short seed life), not to mention that they are downright annoying as well! If you think this is just a Queensland problem, think again. This boy band, I mean weed, has risen to fame in recent years as it has spread from its home in Queensland to playing gigs on road verges all over the country. When faced…

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Australian Herbicide Resistance Initiative (AHRI)

Low dose phenoxy resistance

Once upon a time we used to argue about whether smoking was bad for your health. We don’t argue about that anymore. In the world of weeds, we used to argue whether low herbicide rates cause herbicide resistance. We don’t argue about this anymore. Both low rates and high rates of herbicide can cause herbicide resistance, but it seems that low rates are the fast track to herbicide resistance. Dr Mike Ashworth from AHRI, evolved resistance to 2,4-D in wild radish. Mike started with only a few hundred plants of a known herbicide susceptible wild radish population, and in just…

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Australian Herbicide Resistance Initiative (AHRI)

Wild oat resistance takes effort

Many young people don’t like the taste of beer, but they know if they work hard, endure the awful bitter taste and hideous hangovers for a few years, they will eventually like the stuff. It takes effort, but if they stick at it long enough they can get there. And, believe it or not, you have to work pretty hard to evolve resistance in wild oats. But if you stick at the same practice long enough (it takes effort), you can get there! We have previously reported AHRI research showing that wild oats evolve resistance slowly because they are both…

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Australian Herbicide Resistance Initiative (AHRI)

Glyphosate resistant brome – gene amplification

Two years ago, a meeting was held in Australia to gather researchers who study weed, pest and disease resistance to see what they could learn from each other. There was a mind-blowing moment when an entomologist realised that the P450 enzymes he had been studying that gave resistance to an insecticide were the same as those that a weed researcher was studying that caused resistance to a herbicide (well… we thought it was mind-blowing. But then again, we’re weeds geeks!). Some new research by Jenna Malone, Chris Preston and others from the University of Adelaide weed research team have found…

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Australian Herbicide Resistance Initiative (AHRI)

27% achieved it. Can you?

Cricketer Glen McGrath was a specialist bowler, but he couldn’t bat to save himself. NFL punter Steve O’Neil was a specialist kicker. He once punted the ball a record 98 yards, but could he throw? It turns out that seed cleaners are specialists at cleaning seed. Go figure! Research by Pippa Michael (now Curtin) and AHRI researcher Mechelle Owen from 2008 showed that 73% of cleaned crop seed samples had some level of weed seed contamination. The most common weed species found were ryegrass, wild radish, brome grass and wild oat. The kicker? Many of these populations were also herbicide resistant!…

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Australian Herbicide Resistance Initiative (AHRI)

Early flowering wild radish paradox

If you drop a piece of toast, it will land butter side down (the likelihood of this is proportional to the price of the carpet). If you drop a cat, it always lands on its feet. But if you strap a piece of toast to the back of a cat, butter side up, and drop the cat, now that is a paradox. If we adopt harvest weed seed control to get on top of the wild radish seed bank, could we paradoxically select for early flowering and early shedding wild radish that can avoid harvest weed seed control, and create…

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