Riverina and Central West farmers are being invited to send feathertop Rhodes grass seeds to the NSW Department of Primary Industries (DPI) for free herbicide resistance testing, as researchers strengthen strategies to manage the weed.

NSW DPI principal research scientist Hanwen Wu, said tests from 22 samples received last year indicated resistance to glyphosate is highly common in southern NSW.

“We found no resistance to haloxyfop (Group 1) and need more samples from cropping paddocks to determine the overall resistance status in southern NSW,” Dr Wu said.

“Samples from cropping paddocks only are needed, ideally 30 mature seed heads with tiny black seeds from 10 different plants in each paddock.

“We know glyphosate control of feathertop Rhodes grass has been variable in southern NSW and Group 1 herbicides are prone to developing resistance.

“With feathertop Rhodes grass continuing to spread south, where it devalues pasture and reduces productivity, this survey will allow us to benchmark herbicide resistance in southern NSW to help growers better manage this invasive weed.”

Test results will be sent directly to farmers and will help inform a joint GRDC and NSW DPI research project. Led by Dr Wu, the project is investigating management tactics best suited to southern NSW.

Farmers are asked to place seeds in an envelope labelled with the date of collection, with their name, mobile phone number, nearest town and GPS location, if available.

Send samples to:

Feathertop Rhodes grass
NSW DPI
Wagga Wagga Agricultural Institute
PMB Pine Gully Road
Wagga Wagga NSW 2650