Comprehensive study reveals cost of weeds to WA growers

Author: Natalie Lee | Date: 13 Apr 2016

Two men holding a report and smiling while looking at the camera.

Looking over the Impact of weeds on Australian grain production report are GRDC General Manager Crop Protection Ken Young (left) with principal report author Senior Research Scientist (Farming Systems) Rick Llewellyn.

Photo: Nicole Baxter, Coretext.

Australia’s most comprehensive analysis of the cost of weeds in cropping systems has shown that the overall annual cost to Western Australian grain growers is $927 million or $117 per hectare.

The Grains Research and Development Corporation (GRDC) commissioned report Impact of weeds on Australian grain production also shows that growers are investing heavily in weed management and, despite increasing levels of herbicide resistance, in-crop weed populations are mostly being kept low.

GRDC General Manager Crop Protection Ken Young said the industry study into the cost of weeds -including yield losses and the costs of weed management practices – had input from 600 growers, as well as agronomists, consultants, agribusiness data experts and researchers.

“Weeds present one of the largest costs to grain growers and are one of the biggest influences on the management of cropping systems,” Dr Young said.

“This study is the most comprehensive review to date on the cost of weeds to Australian grain growers and the adoption of weed management and tillage practices, and will help guide future decisions on cropping systems research, development and extension.”

CSIRO Senior Research Scientist (Farming Systems) Rick Llewellyn, the lead author of the report, said that while the study identified important differences between regions and agro-ecological zones, key results at a national level included:

  • The overall cost of weeds to Australian grain growers is $3.3 billion annually
  • Weeds are costing Australian grain growers on average $146/ha in expenditure and yield losses
  • Average expenditure on weed control, including herbicide and non-herbicide practices, is $113/ha
  • Yield losses due to weeds amounts to 2.76 million tonnes of grain
  • The most expensive weeds in terms of total yield losses are annual ryegrass, wild radish and wild oats, with brome grass being a notable major weed that is increasingly costly.

Dr Llewellyn said the costs of yield losses due to weed competition ($708 million nationally) were much lower than total weed management costs ($2.6 billion).

“Reducing the cost of weed management is one of the grains industry’s largest challenges,” he said.

Dr Llewellyn said that as weed control through cultivation had declined, adoption by growers of a range of other weed management practices had increased.

“Crop-topping, double knockdown and narrow windrow burning have increased, with the latter showing rapid recent increases in some areas, particularly WA,” he said.

Dr Llewellyn said WA growers were leaders in the adoption of harvest weed seed control (HWSC) practices which, when combined with other control measures, played a crucial role in reducing weed populations and weed seed banks, and minimised the impact of herbicide resistance.

“The total national cost of using HWSC practices – such as narrow windrow burning, chaff carts, the Harrington Seed Destructor and chaff tramlining - is estimated at $17 million annually, with $13 million of this in WA,” he said.

“WA has more than three times the per hectare expenditure on HWSC compared with the other regions, but other regions are now following the WA lead and practices such as narrow windrow burning are increasing rapidly.”

The GRDC report Impact of weeds on Australian grain production is available here.

The GRDC, which invests in grains research, development and extension (RD&E) on behalf of Australian grain growers, has a significant ongoing investment in the area of weed control and herbicide resistance.

These investments include $45 million over five years into a ‘Herbicide Innovation Partnership’ with Bayer CropScience which aims to discover and develop innovative weed management solutions.

The GRDC also has a $1.5 million annual investment in the Australian Herbicide Resistance Initiative (AHRI), based at The University of Western Australia.

Analysis shows that GRDC investment into the area of herbicide resistance alone over the past 25 years has returned a benefit-to-cost ratio of $3.50 for every dollar invested.

Contact Details

For Interviews

Rick Llewellyn, CSIRO
08 8303 8502, 0429 690 861

Ken Young, GRDC
02 6166 4500


Natalie Lee, Cox Inall Communications
08 9864 2034, 0427 189 827

GRDC Project Code CSA00043

Region West