Securing Australia from PNG biosecurity threats : final report 2015/046

Abstract

Papua New Guinea (PNG) is the centre of diversity for several Saccharum species (S. officinarum, S. edule, S robustum) and supports indigenous pests and diseases of sugarcane. These threaten Australian commercial sugarcane production, but also directly affect commercial sugarcane yields at the only PNG sugar estate at Gusap, Morobe Province. Two major diseases (Ramu stunt, downy mildew) and a group of pests (moth borers) are recognised as the most important biosecurity threats. Australian scientists have been working in PNG for over 30 years to develop better management strategies for these organisms. A previous project (2009/033) progressed diagnostics and resistance screening research but further work was required. The current project investigated pathogen diversity and diagnostics for Ramu stunt / downy mildew, developed a rapid DM varietal resistance screening test, developed a rapid moth borer screening test (Scirpophaga excerptalis) and researched an artificial diet for S. excerptalis. This research will assist the development of improved detection and management of an incursion into Australia while improving productivity in PNG. Research identified possibly four Peronosclerospora taxa where only two were thought to be present previously, three of which may be new species. Pathogen variation was also identified in the tenuivirus causing Ramu stunt. Variation in both pathogens may lead to unexpected susceptibility in previously resistant varieties. The identified tenuivirus was shown to be the cause of Ramu stunt, while Eumetopina flavipes was confirmed as the virus vector. A rapid method for DM resistance screening was developed, as was a preliminary rapid test for resistance to S. excerptalis.