Water hyacinth has been given the dubious honour by the UN of the world’s most troublesome weed. Since its introduction as an ornamental it has attained a pan- African distribution. It prevents transport, fishing, commerce, the generation of hydroelectricity and increases incidences of malaria, bilharzia, filariasis and encephalitis. We are studying the potential of using a fungal pathogen as an environmentally friendly method of control. Field surveys and laboratory tests have identified those ...