Title: Ryegrass a herbicide-resistant weed concern
[Stock & Land - Thur 17 Dec, 2009: p20] RESISTANT ryegrass has now become a concern for most crop growing farmers in South West Victoria. As the ryegrass seed can travel by stock and machinery, the spread of resistance to known herbicides has become a wider concern with every growing season. To review this current status an Integrated Weed Management survey has been conducted by Southern Farming Systems (AFS) through the University of Adelaide covering longerterm cropping areas of SW Victoria.
During the last couple of weeks, SFS collected samples from five districts, covering Inverleigh, Skipton, Lismore, Willaura and Lake Bolac. Within those five regions, 104 paddocks were surveyed for ryegrass herbicide resistance.
Ryegrass samples were taken randomly from 20 meters from any fence or boundary. A maximum of 100 spikes were collected or as many spikes that could be found within a 30 minute lime period.
Any observations about the paddock where the samples were collected were noted and GPS co-ordinates were taken so that any fonnd herbicide resistance could be tracked. The crop varieties that were snrveyed were wheat, canola, barley, oats and one paddock of peas. The collected spikes have now been sent to the university to be analysed along with samples collected from other regions.
Out of the 104 surveyed paddocks by SFS, 100 spikes of ryegrass were collected within the allotted time in 63 crops, with only 10 paddocks not containing ryegrass. Out of all of the different crops that were surveyed, barley crops contained the highest percentage of ryegrass plants.
The area surveyed surrounding Lismore contained the highest percentage of paddocks where ryegrass could be found.
Further information from this survey will be available in autumn 2010.