Effectiveness of various herbicide strategies for controlling the mature Cyperus aromaticus (Navua sedge).

Abstract

Managing infestations of the tropical weed Navua sedge (Cyperus aromaticus), known for its resilience and invasive nature particularly when established via rhizomes, is difficult. This study evaluates the efficacy of six herbicides (sempra, glyphosate, paraquat, imazamox, imazapyr and MCPA) in controlling Navua sedge infestations originating from rhizomatous growth. This research seeks to identify the most effective strategies for mitigating Navua sedge infestation in Northern Queensland by assessing application timing, dosage, mode of action, and combinations of herbicides. The controlled experiments measured the suppression of potted rhizomatous Navua sedge plants under glasshouse conditions. Fifteen herbicide treatments were evaluated for two growth stages (pre-flowering, and flowering) and mowed plants. The impact of various herbicide treatments was recorded using a visual score system, and the number of green tillers in each treatment pot was recorded every 6 weeks. After 18 weeks of herbicide spraying, the dry weight of the above-ground plant and rhizomes were recorded. The germination potential of seeds collected from treated plants was also tested. The findings identify potential tailored herbicide treatments that may effectively control Navua sedge infestation in the field. This research offers practical solutions for combating the threat of Navua sedge in Northern Queensland and similar environments.