Identifying herbicide-resistant weeds enables producers to avoid using herbicides that are no longer effective against herbicide-resistant weeds, and
provides valuable information to researchers about the incidence of herbicide resistance. This information is essential to efforts to limit the development and spread of herbicide resistance.

Testing is conducted on seeds submitted to the testing service. At present, the weed species that are routinely screened include annual ryegrass, wild oats, barley grass, brome grass, and wild radish. Seed of other weeds can be submitted for evaluation, but dormancy issues may prevent accurate determination
of resistance

Download the 2025 order form

QR Code link for report

Annual reports

A summary of findings for previous years can be found in the annual reports:

Questions about the herbicide resistance screening program should be directed to John Broster.

The data from the first 25 years of the herbicide resistance testing service has been analysed and these maps were created from this analysis.

The full analysis of the over 5000 ryegrass samples supplied to Charles Sturt University over this 25 year period can be found online at Broster, JC, Pratley, JE, Ip, RHL, Ang, L, Seng, KP (2019) A quarter of a century of monitoring herbicide resistance in Lolium rigidum

in Australia. Crop and Pasture Science 70, 283-293.

For information on how to combat herbicide resistance in crop weeds see the WeedSmart Big 6 recommendations.