Why annual ryegrass is a problem in Australian agriculture

Gurjeet S. Gill, Co-operative Research Centre for Weed Management Systems, Department of Agronomy and Farming Systems, The University of Adelaide, Roseworthy Campus, Roseworthy, South Australia 5371, Australia.


Annual ryegrass (Lolium rigidum Gaudin) is a problem weed of cropping on most soil types found in southern Australia. Such widespread distribution is believed to be due to large genetic variability present in this species. Apart from successful adaptation to varying habitats, this attribute of the species has also enabled it to rapidly develop resistance to most of selective herbicides registered for its control. Herbicide resistant populations of L. rigidum are now found in all cropping regions of southern Australia. This paper presents information on the distribution of L. rigidum in Australia, conditions of its occurrence as well as ecological and habitat characteristics believed to be largely responsible for its success as a weed. Data on area infested and densities present on farms are scarce, making it impossible to accurately quantify economic impact of this weed on Australian agriculture.


Plant Protection Quarterly (1996) 11 (Supplement 1) 193-195.