Author
Harry Evans
h.evans@cabi.org
CABI
Ascot, UK
Presenting author – Marion Karin Seier
Coauthors
Norbert Maczey, n.maczey@cabi.org, CABI, Ascot, UK
Elizabeth Clingham, elizabeth.clingham@sainthelena.gov.sh, Environment, Natural Resources & Planning, Scotland, St Helena
Marion Seier, m.seier@cabi.org, CABI, Ascot, UK
Rebecca Cairns-Wicks, rebecca.cairns-wicks@sainthelena.gov.sh, St Helena Government, Jamestown, St Helena
Robert W. Barreto, rbarreto@ufv.br, Department of Plant Pathology, Universidade Federal de Viçosa, Brazil
Abstract
St. Helena in the South Atlantic – amongst the world’s most isolated islands – has a unique flora with high endemism that is being invaded by alien plant species that pose an extinction threat. Here, we examine the potential for classical biological control (CBC) of three of these species: Fuchsia coccinea (trailing Fuchsia), Austroeupatorium inulifolium (whiteweed) and Schinus terebinthifolia (Brazilian peppertree or wild mango), which were selected according to their current impact on and predicted threat to the island ecosystems. Preliminary surveys in southern Brazil revealed promising CBC agents on trailing Fuchsia – including a highly-damaging, witches’ broom-forming mite (Aculops fuchsiae, Eriophyidae) – as well as on whiteweed. Both weeds are highly invasive in the upland, humid Peaks National Park of St. Helena, whilst A. inulifolium is also problematic in agriculture. In contrast, Schinus terebinthifolia is confined to the dry, lowland areas where it has been implicated in the decline of native habitats and the lack of regeneration of endemic gumwoods. Past entomological surveys, targeting S. terebinthifolia in southern Brazil, identified a damaging species of thrips, Pseudophilothrips ichini (Phlaeothripidae), and this has since been released in Florida; whilst a serious die-back disease was investigated in more recent surveys. The suspected causal agent is a novel species, Claviradulomyces schini, belonging to a new family of the Ascomycota, Claviradulomyceae.
Keywords
Fuchsia coccinea
Austroeupatorium inulifolium
Schinus terebinthifolia
Brazil
Island invasives
Highlights
Addressing priority weed targets in a highly invaded isolated island system
Existing and new BCAs with a potential to relieve pressure on critically threatened endemic trees
Promising arthropod natural enemies already identified in southern Brazil