Prospects for biological control of Sphagneticola trilobata: Candidate agents from native range

Abstract

Sphagneticola trilobata (L.) Pruski (Singapore daisy) is a fast-growing, sprawling species known for its aggressive and invasive nature. Native to Mexico, Central America, and northern South America, it has spread widely throughout tropical and subtropical regions of the world. Singapore daisy is a novel target for biocontrol, and extensive surveys of arthropod herbivores have recently been conducted in Mexico. To date, over 200 insect specimens have been collected and pinned for identification, representing ~34 morphotypes and one eriophyid mite species. Several damaging arthropods were consistently associated with S. trilobata, including the xylem-feeding spittlebug Clastoptera compta, the leaf-mining moth Astrotischeria selvica, the leaf-tying moth Herpetogramma salbialis, a leaf-mining agromyzid, a shoot-tip feeding weevil, a flower-feeding weevil, and the eriophyid mite Acalitus comptus. Species identification has been challenging, particularly for the weevils and flies. The spittlebug C. compta was first to be imported and host-tested in Australia but was found to be not host specific. Other potential candidate agents include the leaf-mining agromyzid and A. comptus, both considered promising due to their narrow host range and capacity to inflict significant damage under native field conditions. Importation of A. comptus into the high-security quarantine facility at the EcoSciences Precinct, Brisbane, Australia, has been prioritised.