Field-based ecological studies to assess prospective biological control agents for invasive alien plants: an example from giant rat’s tail grass

1. Biological control (biocontrol) of invasive alien plants is a widely utilised weed management tool. Prospective biocontrol agents are typically assessed through host-specificity testing and pre-release efficacy studies performed in quarantine. However, rearing of the potential biocontrol agents and/or test plants is often difficult or impossible under quarantine conditions. Moreover, practitioners may attain laboratory-artefacts in quarantine, which may result in the potential agent being needlessly rejected. Field-based studies in the weed’s indigenous distribution could overcome these issues.

2. Sporobolus pyramidalis and Sporobolus natalensis (giant rat’s tail grass; Poaceae) are indigenous in Africa but have become problematic invasive alien plants in Australia. A previous biocontrol programme was terminated because the candidate agent could not be reared and tested in quarantine. We performed field-based host-specificity and efficacy studies for prospective biocontrol agents ...