The role of ecology in developing weed management systems: an outlook

This paper discusses the extent to which a knowledge of weed biology and ecology can contribute to the development of weed management strategies. To date, such contributions have been modest and have been constrained by a number of factors that are discussed in this review. In contrast to other pest management disciplines, devising integrated weed management strategies that address a diversity of weed species with a diversity of life history traits is dicult. Because of this diversity, robust systems that require ecological insight beyond that of individual species are needed. Although the contributions have been modest, research ®ndings have helped to shape weed management strategies in a number of important ways. Approaches directed at weed population management have revealed important insights into population equilibria, density- dependent mortality and life stages particularly important in regulating population size. Eco- physiological research has helped to guide the development of biologically e€ective herbicide dosage strategies, whereas mechanistic interplant competition modelling coupled with empirical ®eld studies have aided in the identi®cation of weed-suppressive crop phenotypes. Finally, much has been learned about the in¯uence of control tactics and agronomic measures on the evolution of herbicide resistance and the development of integrated weed management strategies to address it. In this paper, examples are reviewed where research in ecology and biology has helped to shape the practice of integrated weed management. More importantly, characteristics of such research programmes are identi®ed so that future e€orts in the discipline will have a context in which the relevance of research questions and approaches can be considered.