Cottonbush invasion in Western Australia: ecology and social perspectives

Mariana Campos, Kathryn L. Batchelor, Karen Bell, Michael Davy, Mike Christensen, Raphael Didham, Bruce Webber

Research output: Chapter in Book/Conference paperConference paperpeer-review


Gomphocarpus fruticosus (L.) W.T.Aiton (narrowleaf cottonbush, hereafter referred to as cottonbush) is a weed of concern in Western Australia (WA) threatening agricultural and natural ecosystems. It is a declared weed (C3 Management) in the state, widespread and established, for which eradication is unfeasible. Management currently attempts to reduce abundance or range and sometimes contain spread. However, the extent of the threat and most appropriate control solution(s) remain largely unknown, and there are strongly contrasting views on optimal management. Here we address priority knowledge gaps on biology and ecology of cottonbush invasions in WA and clarify social perspectives on the weed through citizen scientist elicitation and stakeholder survey. Natural enemies were documented via 13 field surveys across five sites. Two new natural enemies were observed in WA: Arocatus rusticus (Stål, 1866), a seed-eating Lygaeidae, and a phytoplasma causing phyllody. Estimated population seed production came to ~1.7 million filled seeds.ha-1.year-1, of which 1.36 million are viable and not dormant. Seeds readily germinate in optimal conditions 1-30 days after forming, indicating no after-ripening period. The stakeholder survey assessing cottonbush impacts with 101 respondents indicated that perceived environmental and economic impacts are not of significant concern. The issue of poorly managed neighbouring properties (private and government) was repeatedly raised.
The outcomes of cottonbush management in WA are ineffective at present and we expect that threats from this weed could worsen. We recommend further work to reassess the risk profile of cottonbush at regular intervals and prioritise improvements in the efficiency, effectiveness, and equitability of management programs.
Original languageEnglish
Title of host publicationProceedings of the 22nd Australasian Weeds Conference Adelaide September 2022
EditorsRachel Melland, Chris Brodie, Jason Emms, Leah Feuerherdt, Susan Ivory, Shauna Potter
Place of PublicationAdelaide
PublisherCouncil of Australasian Weed Societies (CAWS)
Number of pages4
ISBN (Electronic)978-0-646-86524-9
Publication statusPublished - Sept 2022
Event22nd Australasian Weeds Conference - Adelaide, Australia
Duration: 25 Sept 202229 Sept 2022


Conference22nd Australasian Weeds Conference
Abbreviated title22AWC
Internet address


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