The effectiveness of herbicides and their combinations for controlling Cyperus aromaticus (Navua sedge) in Queensland

Abstract

Sustainable cultivation of crops plays a crucial role in the agricultural sector, directly influencing both the quantity and quality of the end products. This has a direct impact on the overall profitability of farmers. Weed management is a continual challenge, influencing production costs and practices in agriculture. One such weed is Cyperus aromaticus commonly known as Navua sedge which poses a significant threat to Queensland's agriculture and exhibits a remarkable reproductive ability through its rhizome system and prolific seed production. Traditional herbicides, including Glyphosate, halosulfuron, Hexazinone, Imazapic, Imazapyr, and Monosodium methane arsenate (MSMA), show limited efficacy and often require application above recommended rates when controlling established C. aromaticus population, escalating production costs and posing environmental concerns. The objective of the study was to evaluate the efficacy of six herbicides (Sempra, Glyphosate, Paraquat, Imazamox, Imazapyr and MCPA), at a range of application rates (45, 75, 375, 540, or 1500 g a.i./ha), different adjuvants (Banjo, Pulse or Hasten), sequential applications (one, two or three sequential sprays), combinations of herbicides (Halosulfuron-methyl, Glyphosate, and Paraquat), and different growth stages (pre-flowering, flowering, and mowed stages with established rhizomes) of Navua sedge. The results indicate sequential spraying of Sempra and Imazapyr has a significant effect on controlling the established rhizomatic population of C. aromaticus. These findings enrich the existing knowledge for controlling C. aromaticus in areas of North-eastern Queensland and for the weed populations with similar environmental conditions.