- Restricted. South and Southeast Asia, Africa, South America, Caribbean, Oceania. In Australia, FSM, Fiji, French Polynesia, New Caledonia. Samoa, Solomon Islands, Vanuatu.
- Invasive, aggressive, perennial, grass-like, sedge, with underground stem, producing large amounts of seed, forming dense stands, colonising plantations, rice fields, pastures and replacing native vegetation.
- Height, 30-70 cm. Underground stem produces shoots and roots. Leaves, 5 cm long, at base of a 3-sided stem, with white flowerheads at the top forming a knot of flowers (spikelets) with six, leaf-like structures of different lengths. Seeds, 250 per flowerhead, brown to black, egg-shaped, with hooks. Aromatic smell when rhizome crushed.
- Spread: rhizomes; seed by birds and other animals; footwear; stem pieces during cultivation.
- Biosecurity: Among 10 worst weeds in Fiji, Samoa, Solomon Islands.
- Biocontrol: Little known. Comparison of Asian and Pacific sedges needed.
- Cultural control: dig out and turn over; disc and allow to dry out; heavy rollers (repeating 8-12 week intervals); vehicle hygiene to remove seed; avoid over-grazing pasture (maintain healthy growth).
- Chemical control: in Australia: glyphosate; halosulfuron-methyl. Follow-up treatments required to treat seedlings. In Fiji, MCPA.
Pacific Pests, Pathogens, Weeds & Pesticides
Navua sedge (449)
Photo 2. Thick expanse of flowering navua sedge, Kyllinga polyphylla, showing the leaf-like bracts below the flowerhead.
Kyllinga polyphylla. It was known previously as Cyperus aromaticus. It is a member of the Cyperaceae.
AUTHORS Grahame Jackson, Aradhana Deesh & Mani Mua
Information from 1Waterhouse DF, Norris KR (1987) Kyllinga polyphylla. Biological Control Pacific Prospects. Inkata Press, Melbourne; and CABI (2019) Kyllinga polyphylla (Navua sedge). Invasive Species Compendium. (https://www.cabi.org/isc/datasheet/17492#toPictures); and from Navua sedge, Cyperus aromaticus (2020) Department of Agriculture and Fisheries, Biosecurity Queensland. (https://www.daf.qld.gov.au/__data/assets/pdf_file/0007/51010/navua-sedge.pdf). Photo 2 Jim Space, Pacific Island Ecosystems at Risk (PIER), Bugwood.org. Photo 3 James Cook University, Australia. Diagram Enler A (1910) Die Pflanzenwelt Afrikas, insbesondere seiner tropischen Gebiete: Grundzge der Pflanzenverbreitung im Afrika und die Charakterpflanzen Afrikas. Leipzig: W. Engelman.
Produced with support from the Australian Centre for International Agricultural Research under project HORT/2016/185: Responding to emerging pest and disease threats to horticulture in the Pacific islands, implemented by the University of Queensland, in association with the Pacific Community and Koronivia Research Station, Ministry of Agriculture, Fiji.