Identifying effective post-emergent herbicide treatments for itch grass.

Results achieved by SRA Weed Science Leader, Emilie Fillols, in pot trials to identify effective pre-emergent strategies for managing itch grass, were recently published in the latest issue of Cane Matters magazine (page 10).

Now, Emilie has turned her attention to experiments to screen different post emergent herbicides to see how they perform to control itch grass.

Itch grass (Rottbeollia cochinchinensis) is an issue for sugarcane production in the Burdekin, Central Queensland, Far North Queensland and more recently on the Tablelands.

In a trial being conducted in a greenhouse at SRA’s Meringa Station between October and December 2025, a range of post emergent herbicide treatments have been compared for their efficacy in controlling itch grass.

Thirteen herbicide treatments have been sprayed in a completely randomised design with six replicates. These have been compared with a control – an untreated healthy itch grass plant.

As expected, different levels of control have been obtained with the different herbicides that have been tested.

“The aim of the experiment is to be able to tell growers which post-emergent herbicide treatments SRA recommends to control itch grass in the most efficacious way,” Emilie said.

In this trial, itch grass was sprayed in November when it had grown to about 20 cm tall.

“After the spray, we measured the height of the itch grass twice a week to see whether the herbicide eradicated the itch grass or only limited its growth,” Emilie said.

“We also assessed the severity of herbicide damag.e

“In early December, we measured the biomass left in each plot. In some treatments there was no biomass left.

“However, with some herbicides there had been some level of control but then regrowth appeared.

“These data will be analysed by our biometrician, Isis Arend Da Silva and results will be reported early next year”.

This is the second trial in a series which Emilie has undertaken on itch grass post-emergent control for the past year. The results from these post-emergent herbicide trials will be written up for Cane Matters the magazine. There will also be fact sheets available on the SRA website.

This trial work was undertaken as part of the Far North Queensland District Plan.

Emilie Fillols has also undertaken trial work to assess herbicide control of sickle pod, Navua sedge, wild sorghum and hymenachne. Results will be published as they become available.

Get the fact sheet as a handy reference on controlling itch grass.

Watch the video below: ‘Identifying effective post-emergent herbicide treatments for itch grass’.