JOHNNY Kumpulainen at Beatrice on the southern end of the Atherton Tableland knows first hand just how tough it can be to battle Navua sedge.
Mr Kumpulainen first noticed Navau sedge 25 years ago on a neighbouring property.
By 2016 his entire property was badly infested with sedge and, having had no success in trying to control the pest, Mr Kumpulainen had given up and decided to walk away.
“The local real estate agent told us that being covered with sedge, our property value had halved from around $800,000 to $400,000.
“On top of that, when potential buyers of our cattle said they loved our stock but wouldn’t risk taking them and infesting their own properties with sedge, we knew we were in trouble.
“Last year after a meeting at Malanda, I was very lucky to hear about Nick Matthews looking for a property to demonstrate Navua sedge control, and decided to give it a go.
“Nick’s trials showed us exactly what to do – two sprays with the right herbicide Sempra and 90 per cent of the sedge was gone. After just one season of spraying we saw great results.
“We grazed two weeks prior to the first spray of Sempra. Seven weeks after that first application, the Navua sedge had died. I then slashed to bring the pasture down to a uniform height. A second application of Sempra was made 10 weeks after the first, by which time most of the viable Navua sedge seed had germinated. After having sedge for so long, and knowing there’d be a heavy seedbank in the soil, we were keen to get the spray right down to the seedlings.
“We’re on the wet end of the Tableland (receiving more than 1 metre of rain already this year) which the sedge loves, so we know it will take a while to reduce the seedbank down. But at least we know we can now successfully control it. The Nandi setaria and legume pastures have responded well and come back. It’s going to be a long process, but we now feel confident we can kill it.”
Mr Kumpulainen’s main messages to other graziers and landholders was that the registered herbicide Sempra plus Banjo does effectively kill Navua sedge; and to make sure they sprayed before the sedge sets seed.
“You might think it’s expensive, but spraying at the right time before seed-set means millions more seeds are not going to infest your ground.”
He also emphasised the importance of everyone across the region taking Navua sedge control seriously. As a mobile tractor mechanic, he sees the widespread nature of Navua sedge infestation across the region.
“It’s everywhere around the Tableland – on council land and National Parks as well as private properties. Everyone has to work together to get rid of this pest.”