mechanisms

September 7, 2020

Reversing trifluralin resistance

They said it couldn’t be done – climbing Everest, flying to the moon and even deep-frying Mars bars. We were also told that we couldn’t reverse herbicide resistance. In the majority of cases, the experts are right – herbicide resistance is permanent, and we thought that was the case for all resistant weeds.

Until now…

July 13, 2020

On a good thing? Don’t stick to it! – the Director’s Cut

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.

April 7, 2020

Diflufenican resistance in wild radish is by P450s

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…

March 30, 2020

The reality of spontaneous mutation

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 imported from another site of selection as seed or pollen.

The second is ‘de novo mutations’ where the parent plants are both susceptible to the herbicide but a spontaneous mutation in the genes of the progeny renders it (and its progeny) resistant. Resistance that arises this way is very rare and often comes with a ‘fitness penalty’.

March 11, 2020

Luximax gets its own NEW box

We all put things in boxes inside our head to help us organise our brain. A few of the important boxes I have inside my head – fishing spots, great moments in sport, top five meals of all time, jokes, song lyrics, useless trivia, movie quotes, WA town license plates, and of course the nothing box (the place every man retreats to when he has five minutes of peace and quiet!). Ok, it’s not an over-achieving brain but it gets me by.

However, sometimes something new will come along and it won’t fit into your existing boxes. It might need a new box.

Knowing how to use a new product in mixes and rotations with other herbicides can be a little confusing, hence the development of the “boxes” by the AHRI team a couple of years ago to help you put the right herbicides in the right boxes inside your head.

So, when considering this, what box do we put Luximax (Cinmethylin®)? Well… it gets its own NEW box!

AHRI researcher Dr Roberto Busi is helping us to understand some of these new products before they come to market. He recently investigated the product Cinmethylin which is a new BASF product called Luximax

February 12, 2020

Group H (HPPD) resistant wild radish

The first resistance to HPPD herbicides in wild radish has now been discovered by AHRI researchers led by PhD candidate Huan Lu. Wild radish is just the third weed in the world to evolve resistance to this group of herbicides. The wild radish in this research was resistant to several other groups of herbicides which may have led to metabolic resistance to HPPD.

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!

November 11, 2019

World’s first metabolism-based glyphosate resistance discovered

Wine casks, plastic banknotes, WiFi, the refrigerator, lawnmower and the humble ute (pickup truck) are all Australian, world-first inventions. Which of these makes the biggest difference in your life? As long as it’s not the wine cask you’re doing just fine!

We now have a world first in herbicide resistance. research by visiting Chinese researcher to AHRI, Dr Pan Lang under the watchful eye of Qin Yu, concluded that they were looking at the world’s first case of metabolism-based resistance to glyphosate. The culprit? Click through to find out!

October 4, 2019

Revealing canola’s super-powers

This AHRI Insight is a follow-up on an earlier article ‘Crops are doin’ it for themselves’ to where we investigated the complex interactions of competitive crops and their weed suppression powers.

While that paper focused on cereals, in this one we will consider the mechanisms at play in canola, a crop from the mustard family, long known for its allelopathic ability and yet the exact mechanisms are still shrouded in mystery.

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?