DPIRD’s summer skeleton weed search takes to the air in eradication program

The summer search campaign for the significant agricultural plant pest, skeleton weed, is about to kick off across the grainbelt with ground and drone searching.

Skeleton weed is a declared plant that ties up nitrogen and soil moisture, reducing crop yields.

This year’s search program, led by the Department of Primary Industries and Regional Development in collaboration with seven local action groups, will cover more than 400,000 hectares.

Targeted surveillance activity will cover 200 properties across more than 56,000 hectares to find and map infested areas for follow-up treatment, while additional searching will be undertaken to identify areas where the weed could spread.

Aerial surveillance using drones, or unmanned aerial vehicles, now account for a large part of the targeted surveillance activity, with a total of 22,000 hectares to be surveyed by the devices in 2021-22.

DPIRD project manager Martin Atwell said drones had proved to be a valuable addition to the surveillance activity and the development of the technology was advancing quickly.

“We have learnt a lot about how best to use drones to accurately detect skeleton weed over the past five years,” he said.

“The drones are installed with digital imaging technology to accurately and confidently capture, record and map the presence of skeleton weed to aid eradication strategies and treatments.”

The Skeleton Weed Program’s activities are funded by growers through the Grains, Seeds and Hay Industry Funding Scheme.

While the program provides support directly to landholders in target areas to control the weed, Mr Atwell reminded all landholders to remain vigilant and report observations to the department.

“Harvest is the best time to observe the weed, providing an opportunity for early detection and making eradication more feasible,” he said.

“Skeleton weed is easily distinguished by its bright yellow daisy flowers during summer and autumn, with upright and usually leafless stems, which gives the appearance of the skeleton of a plant.”

A full review of the Skeleton Weed Program in 2019-20 confirmed the value and effectiveness of the program and made additional recommendations to refine the research and development investments.

The overall aim of the research program is to reduce the level of new infestations and or increase the level of cleared infestations so the overall infestation is decreasing or constant and includes herbicide trials, precision mapping and historical data analysis.

DPIRD senior research scientist John Moore said he was using several methods to decrease infestations including time lapse photography to examine emergence of the weed, machine learning to aid detection, microwave weed destruction and preparation for biocontrol.

“The cutting edge research is combining image analysis with machine learning to detect skeleton weed plants, to determine if new plants are coming from old crowns or dormant rootstocks or seedlings,” he said.

“The same technology is also being used to determine the effect of skeleton weed treatments on crop growth.”

DPIRD researchers are also examining the use of microwave radiation to kill skeleton weed in small sensitive areas, where chemical treatments are inappropriate.

Any suspect skeleton weed plants should be reported to DPIRD using the MyPestGuide Reporter app or to the department’s Pest and Disease Information Service on 9368 3080 or padis@dpird.wa.gov.au.

To find out more, visit agric.wa.gov.au/skeletonweed.