Abstract
D. insularis is an aggressive perennial grass causing major weed problems in its native area, especially in Brazil, Paraquay and Bolivia. It was classed as a principal weed in Venezuela by Holm et al. (1979). It is a major weed where introduced to pastures in Hawaii, USA (Kuswata Kartawinata and Mueller-Dombois, 1972); also in Papua New Guinea (Chadhokar, 1978). In Hawaii, a weed risk assessment based on the Australia/New Zealand model rated the species at 20, i.e. high risk (PIER, 2012).