Editorial By John Lovett

John Lovett

The discovery of two populations of glyphosate-resistant annual ryegrass in NSW should be ringing alarm bells throughout Australia's grain-growing areas. These two populations have been tested by the Cooperative Research Centre for Weed Management Systems and the University of Adelaide Waite Centre.

If ryegrass resistance becomes more widespread, the negative impact on Australian growers will be huge.

The researchers estimate that glyphosate (Roundup) is now used to protect up to 90 per cent of all Australian wheat crops. Arguably, glyphosate is the most important herbicide for agriculture, worldwide.

In Crop Clinic of this Ground Cover we look at some of the most recent findings from a growing body of research that shows how to manage weeds, annual ryegrass in particular, without over-reliance on one chemical.

The message from this research work supported by the GRDC is clear: best-practice weed management means rotating groups of chemicals and making the most of other tools such as crop rotation and mechanical weed control, for example ryegrass seed collection.

Growers in the southern and western grains regions are receiving a complimentary Paddock Diary. This will be useful in keeping track of herbicide group rotations in grain paddocks.

In this Ground Cover we also look at the upsurge in canola cropping in NSW and the hopes for herbicide-resistant transgenic varieties already in wide use in Canada. While these transgenic varieties, particularly Roundup-resistant canola, are eagerly sought for trouble-free in-crop weed control, the ryegrass resistance we've just talked about would seriously compromise the new varieties.

This Ground Cover looks ahead to the next season, focusing on new varieties, roadtests, tillage equipment, weed and disease management. It's worth

remembering that new varieties can only perform as well "as sustainable practices allow — that's both in soil management and weed control.