Silverleaf nightshade (SLN) is an introduced perennial weed with a deep root system that is very hard to kill. It reduces crop and pasture yields for farmers in the wheat-sheep zone of Australia. In 1992 South Africa released a beetle (SLN leaf beetle – SLNLB) from North America to eat SLN. It was very successful, and so this project aimed to test whether it was suitable for release in Australia.
A team of seven scientists based in Adelaide (PIRSA and DEW), Melbourne (DEDJTR) and Wagga Wagga (NSWDPI) joined forces to work on the project. It was funded by the Australian Government, MLA, PIRSA and SAGIT. SLNLB was imported into Melbourne under quarantine laboratory conditions and was offered a wide range of native plants and crops closely-related to SLN.
Unfortunately, the SLNLB fed on 15 native plants as well as eggplant. In late 2017 it also attacked a group of related potato varieties, something not recorded by the South African researchers. The research team immediately ruled out SLNLB as suitable for release in Australia. Although not successful in releasing the beetle, the project undertook thorough and detailed processes to ensure that integrity in the testing procedures was followed. This project provided a significant amount of new information, and a large seed collection, that will be invaluable for future biological control projects against SLN.