Oral Presentation Society of Environmental Toxicology and Chemistry Australasia 2021

Glyphosate: Assessing the alternatives for vegetation management (#100)

Jackie H Myers 1 , Erica O'Dell 1 , Andrew Kleinig 2 , David Cleeland 2 , Belinda Lovell 3 , Mark Jarvis 2 , Rhys Coleman 4 , Vincent Pettigrove 1 , Erica O'Dell 5
  1. A3P, RMIT University, Bundoora, VIC, Australia
  2. Waterways and Catchment Operations, Melbourne Water, Melbourne, Victoria, Australia
  3. Waterways and Biodiversity, Melbourne Water, Melbourne, Victoria, Australia
  4. Applied Research, Melbourne Water, Melbourne, Victoria, Australia
  5. AQUEST, RMIT University, Bundoora, VIC, Australia

Glyphosate, a broad-spectrum systematic herbicide, is the most routinely used herbicide by local government agencies and the Water and Natural Resource Management industry as it’s considered the most effective and economic solution to control weeds. It’s used for the management of weeds along waterways, rights of way, industrial areas, and at sites where alternative forms of control (e.g., physical control)are often less successful, practical or economical. However, concern over the human health and environmental impacts of glyphosate use has risen considerably over the past decade and led to many agencies considering the reduction or elimination of glyphosate from their weed control programs.

To reduce the use of glyphosate for weed control, suitable alternatives need to be identified and assessed. Alternative approaches need to be safer for the operator, community and environment, effective at managing weeds, and be cost efficient.

Field experiments along grassed fence lines were conducted assessing the effectiveness of three alternative approaches to weed management (brushcutting, edge mowing and Heatweed method) in comparison to Glyphosate. Treatments were applied on a single occasion at nine sites across Greater Melbourne in Summer 2020 and in Autumn 2021. The effectiveness of the alternative approaches was measured by assessing weed type, density and growth at fortnightly intervals over 3 months.

Initial results indicate that brushcuttingand edge mowing provide an immediate reduction in vegetation cover, however, the effectiveness of these treatments was shorter-lived, lasting 20-30 days before vegetation density reaches pre-treatment conditions. Heat weeder applications showed greatest similarity in effectiveness to Glyphosate, with effective vegetation control lasting for up to 60 days following treatment. Alternative chemical options are also to be assessed in future trials.

The effectiveness of the mechanical and heat approaches in comparison to glyphosate will be discussed as well as opportunities for their incorporation into large-scale integrated vegetation control programs.