Palmageddon: the wasting of ornamental palms by invasive palm weevils, Rhynchophorus spp.

Abstract

Urban areas landscaped with ornamental palms, especially Canary Islands date palms (Phoenix canariensis), are particularly vulnerable to incursion by invasive palm weevils, Rhynchophorus spp. (Coleoptera: Curculionidae). Metropolitan palmscapes are often resource rich in terms of palm species diversity and density, and these areas typically have numerous conduits (e.g., air, road, or sea transportation hubs) that assist with international and regional trade and tourism which can facilitate accidental or deliberate weevil introductions. Once established in urban areas, Rhynchophorus populations may be hard to suppress, from where they can expand their range and threaten agricultural commodities or native palms in wilderness areas. Here, we review current knowledge about relationships between Rhynchophorus invasions and urban environments. Further research areas should be addressed to improve forecasts of invasion risks and to complement management options for detection and control. We propose that greater attention be paid to quarantine restrictions on live palm movements and pro-active early detection and monitoring programs in areas deemed to be at high risk of invasion and establishment. In response to an incursion, we advocate the deployment of containment and eradication campaigns in urban zones when populations are small and highly localized.