Herbicide resistance is an ever increasing hurdle for sustainable agriculture, not only in Australia but worldwide. Currently there are 319 resistant biotypes of 185 weed species that are resistant to herbicides from the majority of herbicide mode of action groups across the globe (Heap 2008). To glyphosate alone there are 13 resistant species world wide, two of which include populations of awnless barnyard grass and annual ryegrass in Australia. A closer examination of the situation in Australia shows that there are populations of 34 weed species resistant to 12 herbicide mode of action groups (Table 2 contains a list of these groups). Whilst the majority of these species are located in southern Australia, a significant number of these weeds are those that can be found in cotton growing regions, whether in the cotton crop itself or in other parts of the rotation