In West African countries, fishers have been hard hit by water weed infestations. The weeds, and water hyacinth in particular, slow down their boats and make landings difficult, and as a result, much of their catch decays. Boats also use more fuel to get through the heavy weeds and increased costs are then reflected in consumer prices. - - General: General. The water hyacinth is native to South America. Experts suspect it was brought to Africa in the 1980s by botanists and gardeners as an ornamental plant. However, it is now classed as a water-weed.

Water-weeds cause a lot of damage to the environment. They make waterways unnavigable, reduce the generating capacity of hydro-electric stations and block irrigation canals. By clogging sewage and drainage systems, they can cause flooding, contaminate drinking water and create breeding grounds for harmful insects and bacteria.

Water-weeds also contribute to water shortages. They absorb water and then release it through transpiration. As a result, water losses can be more than three times higher in weed-infested water bodies.

in 1995, FAO became one of the major technical executing agencies in a five-year project to control water hyacinth on lake Victoria using biological methods. This project has succeeded in reducing the weed in the lake by more than 60 percent.