This AHRI insight is not for the faint-hearted. This recent AHRI research by Chinese postdoc Hongju Ma and others documents the first case of metabolic resistance to metribuzin in ryegrass in Australia. The ryegrass in this population was only about 3 fold resistant to Atrazine and Metribuzin. The researchers used a P450 inhibitor, PBO, and radiolabelled metribuzin to help determine that the resistance is metabolism-based, likely due to P450 enzyme activity.
Welcome to the highlight reel of AHRI’s recently released blockbuster – ‘Don’t stick to it!’. Set in the labs, glasshouses and fields of this world-leading research powerhouse, and featuring renown giants of the herbicide resistance world – Powles, Busi, Yu and Owen, this latest exposé will have you seriously impressed! ‘Don’t stick to it!’ delves into five years of ground-breaking scientific discovery and its value to Australian farmers in their epic battle against profit-sucking weeds.
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.
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.
Every parent knows that we simply can’t have favourites. We must love each of our children equally. We at AHRI shouldn’t have favourites. We love all weeds research papers equally, but this paper is perhaps a little more equal! It is the work of Martin Harries from DPIRD involving a six-year focus paddock survey with data from 184 paddocks spanning 14 million hectares of cropping land in Western Australia, made possible with GRDC investment. Martin has recently published the weeds aspect of this research as part of his PhD and reported that we’re having a win with weed control in…
How many hours did you spend out in the paddock with a chipping hoe when you were a kid? Do you still carry one in every ute? Chances are you know how effective they are; but wouldn’t mind if you never had to use one again! Australia has an unfortunate habit of claiming world-firsts in new species for the herbicide resistance lists. Fortunately, we have also been leaders in the development of new tools to help combat the problem. Enter: the revolutionary new chipping hoe! The latest of these developments is the world’s first site-specific mechanical weeder.
Work up, work back, seed. That was the system. Then along came no-till. Spray a knockdown, seed in one pass. Game changer. Then came a more variable climate and a suite of pre-emergent herbicides that made early and dry seeding possible. And now we have seed early at all costs, dry if necessary, and get the crop up and away on the first rain. But what does this do for weeds? Should we delay sowing and wait for a knockdown, or have we got it right?
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?
In 1999 I was refuelling my car at a petrol station in Geraldton when I bumped into Dave, a technician with the local Department of Ag. Dave told me he had just returned from a trial where wild radish had survived 600 mL/ha of diflufenican (e.g. Brodal®). This was three times the maximum label rate and six times the common use rate at the time. I could see the entire lupin industry unravelling in front of my eyes. Lupins were a huge success story on our sandplain soils in the area, wild radish was their main Achilles heel…
Not surprisingly, de novo mutations are quite rare in the real world – but even rare things can happen if the population is large enough. When it comes to the evolution of herbicide resistance, there are two biological pathways. The first is simply natural selection where a small number of the population can withstand a particular stress (e.g. herbicide), they set seed and eventually their progeny are the majority, and they generally thrive. Resistant alleles may prolificate at the site of selection (i.e. due to frequent and regular use of a particular herbicide at that site) or they might be…