Digging down on dieback
26 August 2021
Alistair Corr knows that to manage pasture dieback, you need to understand what it is you’re actually dealing with.
He first noticed the condition on the properties he manages for Mactaggart Pastoral in the summer of 2016–17 and has since watched it spread comprehensively across the buffel-based pastures.
“A few years ago, we’d noticed dieback but hadn’t felt the impact of it,” Alistair said.
“A year later, we did a grass budget in April to work out pasture rationing for the dry season, but we realised by September the grass we had available just wasn’t there because the dieback had significantly reduced the available pasture.
“It was a really significant moment because it put us on this progressive learning curve, looking more closely at the condition and the ways we can manage and build buffers against it.”
Know what you’re looking for
Alistair started to explore the mealybug as a causal agent of dieback in early 2021 after hearing Queensland University of Technology dieback researcher Associate Professor Caroline Hauxwell speak at a field day at Banana.
“We decided to get involved in the research by looking for mealybugs on the properties and counting numbers if we found them,” Alistair said.
“It was really interesting that once we started to look for them, it became apparent that they were in all the affected pastures.”
Alistair said a key reason they were able to find mealybugs was because they understood how to locate them.
“They’re tricky to see if you don’t know what you’re looking for, so if you can, get someone to come and show you how to find them in the first instance, which is what we did,” he said.
“You really need to get in and look closely at the plant and in the thatch for them – it can’t be done from a distance.
“Once you get your eye in, it’s actually reasonably easy to see the little white dots in the thatch and on the leaves.”
Finding mealybugs has been a win for Alistair, as he said they’ll be able to monitor them as they become active in the spring and make considerations based on population numbers.
“Everyone is pretty desperate to know what dieback is, so it’s encouraging to know that mealybugs can be identified in affected pastures and are associated with it,” Alistair said.
“Like anything else, if we know what the vector is and can successfully count the population, we’ll be able to start making assumptions about management and what the impact on the business could be going forward.”
Managing dieback
Alistair said pasture and grazing management have been key focuses so far in dealing with dieback.
“We’re watching the grass more closely to ensure it isn’t struggling or grazed too hard, keeping it in a position so that when it rains, it can spring away,” he said.
“We haven’t used burning as a grass management tool on this country, and spraying isn’t something the company is considering at this stage, so pasture management is crucial.”
They are also constantly looking at research findings about dieback, and the control measures others are using.
“With dieback, there’s a lot of work going on, so it’s about keeping an eye on that and using what’s out there to help if it’s suitable.”
