Ethnobiology of Munnozia pinnatipartita (Compositae: Liabeae), an Intriguing Weed of Dairy Farms and Its Use as an Herbicide to Convert Pastures into Cloud Forest in the Otonga Reserve in Highland Ecuador

During the 1960s and 1970s, a magnificent cloud forest near San Francisco de Las Pampas (near Quito, Ecuador) was converted into dairy farm pastures. One endemic composite plant locally called marco yuyo and identified as Munnozia pinnatipartita, has been considered an undesirable weed by dairy farming campesino communities because it negatively affects the introduced grass pasture and is unsuitable as cattle feed. Concurrently, M. pinnatipartita has also been utilized for its herbicidal properties as a deterrent to grasses in a project promoting cloud forest recovery in the Otonga natural park. The peculiarity of this endemic composite utilized as such a deterrent attracted our interest. Accordingly, we investigated its taxonomy, physiology, ecology, and ethnobiology, and managed to demonstrate its potential allelopathic effect on germinating grasses in greenhouse trials. Furthermore, gas-chromatography of potential volatile metabolites identified 25 compounds and, among these, terpenes seem to be primarily responsible for the observed herbicidal effects.