There are two important aquatic alien invasive plant species in Botswana viz., Kariba weed, Salvinia molesta Mitchell (Family: Salviniaceae) and water lettuce, Pistia stratiotes L., (Family: Araceae). Okavango Delta on the northwest and Kwando, Linyanti and Chobe River systems in the northeast of the country have been susceptible to exotic plant invasions due to sub-tropical climate and abundance of aquatic habitats. The native range for these two species is South America, but had been introduced to many parts of the world where they have become problematic. These two 'biological pollutants' cause extensive socio-economic and water resource use management problems in Botswana's wetland systems.