DETECTION AND VARIABILITY OF THE CAUSAL AGENT OF SUGARCANE DOWNY MILDEW

SUGARCANE DOWNY MILDEW is caused by several species in the Peronosclerospora genus including P. sacchari and P. philippinensis. The disease is found in many sugarcane growing areas of the world but was eradicated from Australia in the 1950s. The disease is widespread in the Ramu Agri-Industries (RAIL) sugarcane plantation in Papua New Guinea and causes yield losses of up to 40% in susceptible varieties. This presents a biosecurity risk to Australia and research is being conducted to understand more about this threat. Symptoms of downy mildew have been found in species closely related to sugarcane, including pit-pit (Saccharum edule), noble canes (S. officinarum), wild cane (S. robustum) as well as more distantly related species such as Miscanthus and corn (Zea mays). This paper explores the use of molecular and traditional taxonomic methods to determine the variability and host range of Peronosclerospora species in PNG. Results from this study provide important information that will be used to update the Australian sugarcane downy mildew incursion management plan.