At last, Biological control of Bellyache bush

Abstract

Jatropha gossypiifolia, commonly known as bellyache bush, is a serious weed of rangelands and riparian zones of northern Australia. Since bellyache bush became a target for biological control in 1997, only one agent has been released and this failed to establish. A renewed biological control effort has identified a number of potential agents. A small leaf-mining moth, Stomphastis sp. (Lepidoptera: Gracillariidae), was imported from Peru into quarantine for further research in 2014. Newly emerged larvae mine directly into a leaf and remain there until pupation. No-choice host specificity testing of Stomphastis sp. has been completed for 43 test plant species. The moth laid eggs on numerous non-target species; however development of the agent only occurred on bellyache bush and its congener J. curcas, which is also a weed. Quarantine testing has thus confirmed that the leaf miner is highly host specific and suitable for release in Australia. An application to release this agent will be submitted to the Australian government in the near future. A second agent, Sciota divisella (Lepidoptera: Pyralidae) from India, was imported into quarantine in 2015. The larvae of this moth feed on the leaves, stems and fruit of bellyache bush. No-choice host specificity testing of this agent is in progress. To date, complete development has occurred on five exotic species and two natives. The potential use of the two native species as hosts is being investigated further. Other prospective agents under consideration include a gall midge from Bolivia and a leaf-feeding midge from Paraguay.