herbicide resistance

June 30, 2020

2,4-D resistance – it’s all about perception

This AHRI insight is not for the faint-hearted. It is the work of AHRI researcher, Dr Danica Goggin who has dedicated many years to working out how auxin herbicides such as 2,4-D and Dicamba work, and how plants evolve resistance to them.

Danica’s research found that plants with fewer receptors on their cell membranes were resistant to 2,4-D due to reduced perception of the 2,4-D.

Putting this molecular biology research into words is challenging, so we have created some videos that explain it. 

June 15, 2020

Something old, something new in annual ryegrass control

It’s a quaint tradition that many brides follow – ‘Something old; represents continuity with the past and ‘Something new’ offers optimism for the future. ‘Something borrowed’ passes on another’s secrets for success and ‘Something blue’ represent key features of a solid relationship. Finally, ‘A sixpence in your shoe’ for prosperity. With the release of several new modes of action and chemical formulations, it’s helpful to first consider how these ‘new’ chemicals might revive some ‘old’ chemistry.

April 20, 2020

New-comers causing trouble

How long have you lived where you live? If you’re a long-time local you will have seen new people come and go – some are gone before you get to know them and others stay and find their niche in the community.

Weed communities also change over time and it can take some effort to get to know and understand the new-comers. Will they thrive? Do they fit in? Will they disrupt the way things are done? Or will they go away again, almost unnoticed?

December 20, 2019

AHRI’s top performing insights and podcasts for 2019

We’ve had a fantastic year at AHRI from a research and communications perspective, so we thought it would be fitting to run through some of our top-performing AHRI insights and AHRI Snapshots podcasts for 2019.

December 12, 2019

2,4-D resistance does not affect the fitness of radish

Merv Hughes was not a fit-looking cricketer. Merv was a notorious consumer of food and alcohol, and it showed! Despite this, he was a successful professional sportsman. Mitchell Johnson, on the other hand, was the epitome of a fit, healthy fast bowler. But who had the better bowling average? You guessed it, big swervin’ Mervin!! 28.38 compared to Johnson’s 28.4. Ok, we’re splitting hairs here, but you get the picture, how fit you look is only part of the story.

If you grew 2,4-D resistant radish in pots on its own, and compared that to the good old susceptible radish of yesteryear, you would find that the resistant ones are a bit smaller overall, slightly shorter, have smaller leaves and they are slightly more dormant so they germinate a bit later.

You would think that all of this would add up to a less fit wild radish plant that is less competitive with our crops.

That’s exactly what AHRI researcher, Dr Danica Goggin, thought when she observed these differences in her research to work out how 2,4-D resistance works. So she studied it. Click through to learn what she found!

September 25, 2019

Trending now: herbicide resistance management

‘Trending now’ seems to be everywhere – iTunes, Twitter, the news, so why not herbicide resistance? What have been the #Top5 trends in resistance management over the past decade?

As a young agronomist 20-something years ago (clearly before trending was a thing), I remember learning about the threat of herbicide resistance as if it was a kind of apocalypse. Some growers were genuinely concerned that they wouldn’t be able to continue farming.

We’ve come a long way in a relatively short time. In this insight, we look closely at what’s trending in the herbicide resistance management space.

September 10, 2019

Is there an invisible gorilla in your paddock?

Huan Lu’s been investigating a population of wild radish that has the infamous Ser-264-gly mutation. This is the target-site mutation that is behind TT canola and makes wild radish highly resistant to PSII-inhibiting herbicides like atrazine and, to a lesser extent, metribuzin.

But, he wondered if there was more to this resistance than first meets the eye. Does focusing on the strong 264 mutation mean that we could fail to identify other important resistance mechanisms?

July 2, 2019

Thermal weed control – just hot air, or site-specific reality?

Did you know that rotary hoeing requires less energy than steaming? Or that offset discing requires less energy than microwaving?

Well, that’s the case when it comes to controlling weeds.

An epic effort to review 170 papers by a team from the University of Sydney (Guy Coleman et al) has shown that mechanical weed control options (eg. tillage) can use significantly less energy than thermal options (eg. heat) to kill weeds. Herbicide energy use sits somewhere in the middle.

June 17, 2019

Keep mixing herbicides

Roberto recently completed a project with GRDC investment where he sampled ryegrass from 17 paddocks across eight farms in Western Australia to see if there are benefits of proactively testing for herbicide resistance.  Across these tests, he found ryegrass that was resistant to Clethodim (Select) or Butroxydim (Factor) but no ryegrass that was resistant to the mix of the two. The same went for the pre-emergent herbicides as well, no resistance to mixes.

May 8, 2019

Twenty five years of testing annual ryegrass resistance – it’s a numbers game

Charles Sturt University has sown, sprayed and counted annual ryegrass from around 12 million seeds submitted from more than 5000 samples sent in from across Australia since it started testing for herbicide resistance in 1991…and that’s just ryegrass. Mind numbing stuff. But more than 5000 ryegrass samples? Most tested to five or six herbicides? Think about the value of that information! Dr John Broster and Professor Jim Pratley from CSU have analysed the data from ryegrass samples sent to the testing service over the 25 year period from 1991 to 2015.