Drones, new herbicide and fresh ideas deployed in woody weeds war
Close to 30 graziers and industry representatives gathered at Strathmore Station, Collinsville, in August to see how grazier Paul Fry tackled one of Northern Australia’s most damaging weeds – prickly acacia.
Paul is trialling a new herbicide, Method® 240SL, against the woody weeds, alongside innovative control techniques including drone spraying, basal barking, spot spraying, misting and targeted grazing land management. His goal is to make weed control more affordable, improve ground cover and pasture health, and spend more time managing cattle instead of battling weeds.
Broad-scale weed control experts from PBE Services and Desert Channels Queensland supported him.
Putting Method® 240SL to the test
The trial was part of wider research across Queensland to improve woody weed control. Method® 240SL offers several advantages over existing herbicides:
- Lower application rates
- Strong residual control
- Multiple application options (drone, broadcast, spot-spraying, basal bark, trunk injection, cut stump)
On site one at Strathmore Station, two rounds of drone applications were carried out:
- June 2023 – the first treatment achieved a 98 per cent canopy kill within five weeks. Drone spraying penetrated the canopy to take out seedlings, but some mature plants and rubbervine survived.
- January 2025 – the second treatment used lower flight speeds to increase spray volume. This killed regrowth effectively.
Vegetation surveys (VegCATs) show the treatment has already made a big difference.
Before spraying, the trial site was almost bare, with 95 per cent of the ground exposed beneath a dense prickly acacia canopy.
By April 2024, bare ground had dropped to 38 per cent, with early colonisers such as jutes, angleton grass and armgrass returning.
Key learnings so far
- Spray volume matters – slower drone speeds mean higher kill rates.
- Canopy removal sparks recovery – once light reaches the soil, native colonisers quickly return.
- Seedbanks remain active – ongoing follow-up is critical.
- Rubbervine requires a different strategy – a combination of chemicals may be needed.
From a grazier’s perspective
Paul says the results so far are encouraging, but he is quick to point out there’s no quick fix.
“I’ve invested in drone technology and intend to keep going – this is a long-term investment. What works here on Strathmore might need adjusting elsewhere, depending on conditions. But seeing the ground cover come back is really heartening. The more cover we have, the better protection we get from weeds.”
He is prioritising control around dams, where mature prickly acacia trees produce the most seed and are easily spread by cattle. Once these
high-risk areas are cleared, he plans to expand treatment across paddocks in stages.
“You’ve got to be proactive if you want to maintain productivity. For us, it’s about improving mustering, reducing weeds and building a more resilient landscape.
“We’re thinking about the long game – we don’t want to be doing the same thing 10 years from now. The aim is to see a significant reduction in prickly acacia trees, have a cost-effective plan in place for follow-up, and put more of our effort into maintaining good ground cover year-round while producing high-quality beef.”
This field day was supported by the Landholders Driving Change (LDC2) project, funded by the Queensland Government through the Queensland Reef Water Quality Program.
