Expansion of successful aquatic weed treatment trials
6 May 2026
On the back of successful chemical trials to control aquatic weeds in isolated sections of the Murray Irrigation channel network, the Company is extending this trial to put a dent in the unprecedented buildup of weeds in the Deniboota channel system.
Taking place during the planned Winter Works period this year, the chemical will be applied via direct injection with a drone to parts of the channel still holding water, and via folia spray on the sections that have been drained for planned works.
The Company is optimistic that these extended trials will add another tool to the aquatic weed management toolbox and will help to gradually reduce the demand for mechanical removal.
“This herbicide is the first of its kind to provide low toxicity to wildlife and control most submerged, emergent and floating aquatic weeds”, Murray Irrigation’s Civil Asset Manager John Pearce said.
“Our trials last year provided good results, especially on Sagittaria and floating pondweed.
“While mechanical removal of weeds will continue to be the primary tool used by the company in the short to medium term, we are hoping that the extension of this trial, and the continued innovation from the chemical companies we work with, will lead to wider use of these chemicals which will save costs and the time associated with aquatic weed removal.”
This photo was taken in May 2025 - two weeks after treatment.
This photo was taken in October 2025 - five months after treatment.
This method of aquatic weed control has been used in the American market for weeds in irrigation channels since 2010, and has seen great results.
The active ingredient in the chemical being trialled works by inhibiting chlorophyll production in plants for photosynthesis. In aquatic environments, such as irrigation channels, this produces fast, visible burndown of target weeds.
After treatment, there is no withholding period for pets and livestock, however there is a 14 day withholding period to irrigate food crops and fruit trees, and for domestic use. Murray Irrigation is working closely with customers affected by the trial to manage through the withholding period.
The chemical trials Murray Irrigation is undertaking are being conducted under permits approved by the Australian Pesticides and Veterinary Medicines Authority (APVMA) for both the chemical and drone application with the guidance of the chemical suppliers, Syngenta and Sumitomo.
