Noogoora burr outbreak stymied by drone spraying project

Noogoora burr, a prolific seeder that tangles in sheep's wool, has travelled 19 kilometres along the Amyton Creek near Willowie.

The weed was first identified as an issue in the region three years ago and is considered a threat to farming enterprises and native vegetation.

Fifth generation mixed farmer Peter Barrie is one of 12 landholders involved in the Northern and Yorke Landscape Board project that aims to eradicate the weed and prevent it from moving further downstream.

He said sheep would spread the burr from the creek over the rest of the farm if left untreated.

"Amyton Creek overflows into the Willochra Creek, which flows into Lake Torrens, so there's a large area that potentially can be infested unless we're successful in eliminating it," Mr Barrie said.

Previous efforts to eliminate the weed, by spraying from a quad bike and burying with a loader, were dangerous and ultimately unsuccessful so the Northern and Yorke Landscape Board funded a drone contractor to map and spray the infestation.

Landscape officer Shane Hooper said drone technology overcame the problem of inaccessibility for other spray equipment.

"Getting a boom sprayer down into some of these creeks is quite dangerous and it's not terribly practical to do 19km of creek line with a backpack sprayer," he said.

"With the drones, the operator can sit up on the creek and safely spray, letting the drone do all the work over the rough ground."

The drone contractor mapped a 100 metre wide stretch of the 19km terrain with a specialised mapping drone that takes high resolution video and distinguished the noogoora burr from native vegetation based on colour identification.

After the data was processed, a spray drone treated the noogoora burr plants in ten minute intervals.

The significant down draft caused by the drone propellers, coarse spray droplets and mapping data helped avoid off-target damage of native vegetation.

A challenge faced by the spraying team was the staggered germination of noogoora burr, which was exaggerated by the cooler summer, however both Mr Hooper and Mr Barrie have been impressed with the results.

"So far we've had an excellent strike rate and landholders are working with us to mop up any plants that might have been missed," Mr Hooper said.

"I believe from what I've seen, (drones are) the best way of handling creek lines where there are difficult to control weeds," Mr Barrie said.

"I really think it's got a big place in agriculture. I could see that I'll be using it again for weed control because it's just so much more efficient and so much safer than trying to do it manually."