Biology of the leaf roller Salbia lotanalis and its impact on the invasive tree Miconia calvescens

Miconia calvescens (Melastomataceae) is an invasive alien tree in native forests on some Pacific islands and a potentially invasive species in Australia. Searches for potential classical biocontrol agents have been undertaken for over a decade in the centre of origin (Central and South America). Salbia lotanalis (Lepidoptera: Pyralidae) is a leaf roller which has been recognized as a promising classical biocontrol agent for M. calvescens. This paper presents the biology and an impact study of S. lotanalis on M. calvescens. Life table parameters showed that S. lotanalis has a high reproductive capacity, with up to six generations a year. Miconia calvescens seedlings attacked by S. lotanalis caterpillars had their growth rate significantly reduced. Seedlings subjected initially to a high level of defoliation (80%) caused by caterpillars had leaf fall and a lower leaf area than controls after 210 days. Considering the high population growth rate and significant impact on young plants, S. lotanalis appears to have a high potential for use as a classical biological control agent to be used against M. calvescens.