Leslie Weston is a pioneer in the study and application of plant interactions with other plants, microbes and herbivores. Using advanced techniques in microscopy and chemical analysis she has achieved a fundamental understanding of the localisation of secondary plant products, the process of root exudation, and the transformation of bioactive molecules in the rhizosphere. She has identified the role of various metabolites and biosynthetic pathways involved in plant defence systems, and the regulation of plant-soil rhizosphere interactions. Through intensive study and selection of competitive crops and groundcovers, she has achieved sustainable and effective weed management in diverse agroecosystems.