Navua Sedge (Cyperus aromaticus) is an aggressive perennial sedge native to tropical Africa. It has become a significant invasive weed in northern Queensland, Australia, particularly affecting pastures, sugarcane fields, and natural ecosystems.
Family: Cyperaceae
Growth Form: Clump-forming perennial sedge
Height: Typically 30–70 cm, occasionally up to 2 m
Stems: Triangular in cross-section, arising from extensive underground rhizomes
Leaves: Lance-shaped blades up to 5 cm long, forming drooping clusters at the base
Flowers: White, circular or dome-shaped clusters at the end of a stalk
Seeds: Brown to black, egg-shaped with a hook on one end
Navua sedge thrives in tropical regions with annual rainfall exceeding 2,500 mm. In Australia, it was first reported in the Cairns region in 1979 and has since spread across the Wet Tropics, affecting all coastal councils and beyond. It commonly invades pastures, sugarcane paddocks, wetlands, floodplains, and disturbed areas, forming dense stands that outcompete native vegetation and reduce pasture productivity.
Agricultural: Navua sedge is unpalatable to livestock and can rapidly invade overgrazed pastures, leading to reduced grazing capacity and productivity in beef and dairy industries.
Environmental: Forms dense monocultures that displace native plant species and alter ecosystem dynamics.
Economic: Management and control of Navua sedge are costly and labor-intensive, impacting the profitability of affected agricultural sectors.
Chemical Control:
Herbicides such as glyphosate, halosulfuron, hexazinone, imazapic, imazapyr, and MSMA have been tested for effectiveness against Navua sedge.
Sequential applications and timing (e.g., spraying from March to September) can improve control efficacy.
Mechanical Control:
Methods like slashing, crushing, and rotary hoeing have been less effective and may contribute to the spread due to fragmentation of rhizomes.
Biological Control:
Research is ongoing into biological control agents, including specific fungi that target Navua sedge without affecting other plant species.
Preventative Measures:
Implementing weed hygiene practices, such as cleaning machinery and vehicles, can help prevent the spread of seeds to uninfested areas.
Navua Sedge (Cyperus aromaticus) is an aggressive perennial sedge native to tropical Africa. It has become a significant invasive weed in northern Queensland, Australia, particularly affecting pastures, sugarcane fields, and natural ecosystems.
Family: Cyperaceae
Growth Form: Clump-forming perennial sedge
Height: Typically 30–70 cm, occasionally up to 2 m
Stems: Triangular in cross-section, arising from extensive underground rhizomes
Leaves: Lance-shaped blades up to 5 cm long, forming drooping clusters at the base
Flowers: White, circular or dome-shaped clusters at the end of a stalk
Seeds: Brown to black, egg-shaped with a hook on one end
Navua sedge thrives in tropical regions with annual rainfall exceeding 2,500 mm. In Australia, it was first reported in the Cairns region in 1979 and has since spread across the Wet Tropics, affecting all coastal councils and beyond. It commonly invades pastures, sugarcane paddocks, wetlands, floodplains, and disturbed areas, forming dense stands that outcompete native vegetation and reduce pasture productivity.
Agricultural: Navua sedge is unpalatable to livestock and can rapidly invade overgrazed pastures, leading to reduced grazing capacity and productivity in beef and dairy industries.
Environmental: Forms dense monocultures that displace native plant species and alter ecosystem dynamics.
Economic: Management and control of Navua sedge are costly and labor-intensive, impacting the profitability of affected agricultural sectors.
Chemical Control:
Herbicides such as glyphosate, halosulfuron, hexazinone, imazapic, imazapyr, and MSMA have been tested for effectiveness against Navua sedge.
Sequential applications and timing (e.g., spraying from March to September) can improve control efficacy.
Mechanical Control:
Methods like slashing, crushing, and rotary hoeing have been less effective and may contribute to the spread due to fragmentation of rhizomes.
Biological Control:
Research is ongoing into biological control agents, including specific fungi that target Navua sedge without affecting other plant species.
Preventative Measures:
Implementing weed hygiene practices, such as cleaning machinery and vehicles, can help prevent the spread of seeds to uninfested areas.
