Occurrence of Kariba weed on selected water bodies in Uganda

Abstract

Kariba weed (Salvinia molesta D.S. Mitch.) is a floating aquatic fern that has devastated aquatic production systems worldwide. The objective of this study was to establish the status of occurrence and infestations levels of the weed on the water bodies in Uganda. The study was conducted on purposefully selected water bodies in Uganda, over a period of 2018 to 2022. Kariba weed occurred at varying infestation levels on all water bodies in the country, except on Lake Bisina. The highest number of daughter plants (732 plants per 0.25 m2 quadrant) was registered at Kajjansi, along Lake Victoria. The main impacts of the weed on the water bodies were obstruction of fishing and water transport; and reduced water quality. Given that Kariba weed is dispersed by water currents and vegetatively spread by boats and fishing gears, a catasptrophe in terms of dysfunction of the productivity of the country’s water resources is eminent. Biological control of Kariba weed using Cyrtobagous salviniae weevils is recommended to sustainably manage this devastating water weed.