Annual Ryegrass is a significant weed in cereal production in Western Australia. Herbicide resistance is increasing and is a major concern to producers. Long-term, field scale trials are being conducted on a number of sites in the state. The apparent costs and benefits of different management strategies are dependent on seasonal conditions and markets for inputs and products. This paper presents the results of a simulation model of alternative strategies under a wide range of historic conditions. A conceptual framework for selecting an optimal strategy is explored.