Distribution, threats and management options for water hyacinth (Eichhornia crassipes) in Ethiopia: a review.
Water hyacinth is free-floating, stoloniferous and perennial herb. It is an aquatic invasive species; native to South America and most aggressive invasive species worldwide. It profoundly invaded the tropical and subtropical region of the world, as a result of ornamental properties and reproductive capability of the weed. In addition, it is recognized as one of the worst weeds due to its rapid proliferation rate, ecological adaptability and detrimental effects on environment, human health and economic development. It poses serious socio-economic and environmental problems includes destruction of biodiversity, hindrance to water transport and recreation, oxygen depletion and reduction of water quality, breeding ground for pests, vectors and their effect on human health, hampering agriculture and fisheries, affect hydropower and water supply systems and increased evapo-transpiration. Therefore deferent management strategies such as physical, chemical and biological methods had been used to control the weed. Accordingly manual removal was used in South Africa; Zimbabwe Lake Mutirikwi; Ethiopia Wonji-Shewa Sugar Factory and Owen fall hydropower in Jinja at Lake Victoria. Chemical control was practiced in Zimbabwe Lake Chivero using 2-4-D; South-west Nigeria Ere fishing channel by glyphosate; South Africa larger dams and river systems by using glyphosate; Zimbabwe acetic acid and glyphosate control the weed at experimental site. Biological control was practiced in Zimbabwe Lake Chivero through combination of weevil and fungi; Kenya Lake Victoria and China by two types of weevils (Neochetina bruchi and Neochetina eichhornia) and Ethiopia Neochetina bruchi and fungi at Rift Valley and in green house at experimental level respectively.