RESEARCHERS into herbicide resistance in problem weeds say there have been great breakthroughs in the understanding of how resistance occurs and identifying resistance weeds in a crop population.
While they advised growers not to expect new modes of action to control weed with, they said an increased understanding of the problem being faced meant existing chemistries would be more sustainable.
“We have a couple of exciting new tools which are really helping with our understanding of resistance and where it occurs in the plant,” said Lucy Jackson, scientist with Syngenta at its Jealott’s Hill research facility in the United Kingdom.
“Capacity modelling is something we are using more and more, it is a a method which allows you to model how a different herbicide will impact a species over time.
“It lets us give farmers an idea of exactly what will happen in their paddocks in 15 years’ time rather than simply saying that if you continue to use this product without a break you will run into problems.”
Ms Jackson said the ability to do large scale characterisations of herbicide was allowing researcher to better understand what resistance is out there and how to control it.
“We look at hundreds of weed populations and we get a better idea of exactly what we are combating in each area.”
“We need to know whether we are coming against a target resistance or a non-target resistance, it is no good pouring time into coming up with a solution to the wrong kind of resistance.”
In terms of developments at a farmer level, Ms Jackson said the Syngenta RISQ (Resistance in Season Quick) test was assisting with timely identification of resistant weed populations.
“Small seedlings are gathered and then put in an agar-based solution with herbicide rates at lethal doses for the particular species.”
“If the species doesn’t die within a couple of weeks you know you have a resistance issue.”
Ms Jackson said such in season tests revolutionised combating resistance.
“Instead of having to wait to gather mature seeds and rear them to assess whether there is resistance, taking another season, you can get an answer in just two weeks.”
Ms Jackson said her work at Jealott’s Hill was primarily around supporting current products.
As part of that, there is a strong focus on laboratory testing of resistance.
“We look at whether the gene itself has altered, or whether the resistance is a non-target type, where the herbicide has been broken down by the plant itself and moved around to a spot where it can’t damage the plant.”
Ms Jackson said the agricultural industry was becoming savvier about herbicide resistance and that she felt the Australian example, with resistance to many forms of herbicide would not happen again.
“It’s been a terrible story for Australian farmers, but for the rest of the world we can learn from what happened and ensure it does not happen elsewhere.”
“Eventually I think we will see herbicide resistance slow down, as people realise the need difference for different modes of action in their weed management plans.
“People are much more aware of the need to rotate herbicides and not rely on just one product, so while I imagine it will take time, I think we will see resistance rates globally slow down.”
· Gregor Heard travelled to Europe as a guest of Syngenta.
