Review article on Alternanthera philoxeroides (Mart.) Griseb (alligator weed); an invasive plant species in Sri Lanka and its control measures

Abstract

Alligator weed (Alternanthera philoxeroides (Mart.) Griseb) is an invasive weed in different countries of South America, North America, Australia and Asia. It can grow in range of habitats from aquatic to terrestrial environments. It is one of the non- native plants which was invading natural and agricultural eco systems in Sri Lanka and has recorded as a threat to the native species and thereby to the plant bio diversity. It was an accidental introduction to Sri Lanka due to misidentification as a commonly cultivated leafy vegetable A. sessilis (Mukunuwenna). So it is highly possible to include A. philoxeroides in the market samples of leafy vegetables due to this similarity. A. philoxeroides can propagate through vegetative fragmentation and these vegetative propagules can be dispersed by water in aquatic habitats. An over view of all aspects of A. philoxeroides including its geographical distribution and spread in the world, morphology and ecological aspects, environmental impacts, success of the management options used and present status of this weed in Sri Lanka is presented by this article. Management of alligator weed through chemical, biological, and mechanical means are effective up to some extent in Sri Lanka but it is still a problem in many areas Therefore well-planned, long-term mechanism to evaluate the role of different factors which is responsible for rapid infestation is essential to control the weed. Future research should be focused more on integration weed management approaches in both natural and agricultural ecosystems and to identify the weed from its congener, A. sessilis.