Abstract
Meadows and pastures account for 25 % of land area. To make the best use of these pastures, farmers need to manage the invasive plants that are the main cause of their degradation. Such management requires knowledge of their behavior and, to that end, proper identification. The Wiktrop collaborative portal helps in weed identification and facilitates the sharing and dissemination of knowledge about tropical weeds and their management between field workers and cientists. This helps improve weed control practices throughout the tropics and Mediterranean regions. The contribution of users is an important factor in the quality and scope of the information made available. The portal will soon be expanded to include tropical forage and service plants.