Dr Gavin Hunter ‘Biological control of sea spurge (Euphorbia paralias) in Australia’

Gavin, research scientist at CSIRO will talk about the journey from field surveys in France to host-range testing and field release in Australia to control sea spurge, which reduces nesting spaces for shore birds and amenity to beaches.

Abstract

Sea spurge (Euphorbia paralias) is a fleshy perennial herb native to Western and Southern Europe. In Australia, however, sea spurge is a highly invasive plant of coastal ecosystems along the southern coastline. The weed outcompetes native flora, reduces access to nesting space for native shorebirds and reduces the amenity value of pristine beaches due to the production of a toxic latex when injured. Field surveys of sea spurge in 2008-09 in France for candidate biological control agents resulted in the collection of few insect herbivores and fungal pathogens. Following initial host-range testing performed in France, the fungal pathogen Venturia paralias, proved promising and was eventually imported into the CSIRO biocontainment facility in Canberra in 2017. Extensive host-range testing with the fungus against 44 representative non-target plant species across the Euphorbiaceae, Picrodendraceae and Phyllanthaceae indicated that it only caused severe leaf lesions on sea spurge. Restricted leaf lesions were observed on Euphorbia segetalis, a close congener of sea spurge, which itself is an exotic environmental weed in Australia, while all other non-target species proved resistant or immune to the fungus. These results were considered in the comprehensive risk assessment conducted by the Australian regulator before V. paralias was approved for introduction into Australia in 2020 for the biological control of sea spurge. Since then, CSIRO staff and collaborators in Victoria and Tasmania have actively released the fungus in sea spurge populations along the coastline in those two states. This talk will provide an overview of the research undertaken and the community-based deployment of this first biological control agent for sea spurge in Australia.

Biography                                                                       

Dr Gavin Hunter is a research scientist in the Weed Management Systems group of CSIRO’s Health and Biosecurity business unit. Gavin is a plant pathologist and mycologist with research interests spanning the identification, taxonomy, evolution and population biology of fungal plant pathogens. These interests have been implemented within a biological control context focusing on invasive plants within Australia in order to identify and develop host-specific pathogens for use as classical biological control agents of invasive weeds.

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