The cost of water hyacinth control in South Africa: a case study of three options

Abstract

The aquatic plant water hyacinth (Eichhornia crassipes) was first recorded in South Africa during the early part of the 20th century. The plant has since spread across the country and is found in water bodies in both sub-tropical and temperate areas. The biology, ecology and impacts of water hyacinth are well studied, but sound and cost-effective management of it remains an enormous challenge in South Africa. Since the 1970s, control programmes have focused on the use of herbicides, with some success, while biological and integrated control have historically received less effort and investment, despite the successes of the latter control approaches in other parts of Africa and elsewhere in the world. The reasons for the relative successes and challenges associated with the various control approaches vary substantially. Herbicidal control has been an effective short-term solution with highly visible results. However, the cases used in this study show that herbicidal control is approximately five times (R1 481/ha) less costeffective than either biological or integrated control, mainly because it requires resource-intensive follow-up procedures.