Water hyacinth is the world's worst aquatic weed. It originates from the Amazon basin and over the past 100 years has spread to every continent. The plant has beautiful flowers and has been transported around the world as an ornametal, and has escaped to invest wetlands and waterways all over the world. The weed has several deleterious effects. It disrupts water transport and fishing. It disrupts hydro-electric power generation by blocking water intakes at dams. It seriously depletes aquatic biodiversity (including fish stocks) and affects water chemistry, and it harbours disease vectors (e.g. bilharzia snail vectors) and snakes.
Water hyacinth can be controlled using chemicals and by manual or mechanical removal. However, the only sustainable solution to water hyacinth is biological control. The International Institute of Biological Control, now integrated into CABI Bioscience, has been involved in the control of water hyacinth, using specific insect herbivores, for over 20 years. The IIBC has assisted several countries to find biological control agents and to implement control and is currently executing a project in Malawi with the Fisheries Department of Malawi. IIBC also produces the Water Hyacinth Newsletter for Africa which provides a summary of ongoing activities on water hyacinth control throughout the continent.
A meeting of experts to discuss water hyacinth biological control was held on 18-19 March 1997 in Washington DC. The purpose of the meeting was to assess the status of biological control of the weed and to suggest new directions to improve biological control in the future.
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