Proposed plant host test list for assessing risk of biological control agents for Navua sedge, Cyperus aromaticus

Abstract

The following is a draft test list for potential weed biological control agents for Navua sedge, Cyperus aromaticus (Ridl.) Mattf. & Kukenthal (formerly Kyllinga aromatica Ridl. or K. polyphylla Willd. Ex. Kunth).
Navua sedge is a perennial grass-like plant with a creeping rhizome and densely set culms. It was first detected in Australia in Cairns in 1979 and has since spread along the coast of northern Queensland between Bamaga and Langdon (west of Mackay) and west to the Atherton Tablelands (DAF 2020). In 2011, it was recorded in south-eastern Queensland (AVH 2020). Navua sedge is particularly prevalent in areas with more than 2500mm rainfall per year and no distinct dry season (Figure 2; Parsons and Cuthbertson, 2001). In lower rainfall areas it is restricted to wetter low-lying areas.
In higher rainfall areas of northern Australia, Navua sedge has become a serious pasture weed (DAF 2020). It is an aggressive competitor for nutrients, light, and moisture and can form dense monospecific stands (Vitelli et al. 2010). Reproduction and spread occurs vegetatively by rhizomes and by seed, which are produced in abundance (Parsons and Cuthbertson 2001). Navua sedge has low nutritional value and is avoided by grazing animals (Vitelli et al. 2010).