Potential economic impacts of the wheat stem rust strain Ug99 in Australia

Overview \r\n\r\n Wheat stem rust has been present in Australia for over a century. The most recent and severe outbreak in Australia was the 1973 epidemic. However, a potentially damaging strain of the disease, Ug99, which was detected in Uganda in 1999 and currently not present in Australia, is a major concern as around 30 per cent of Australian current wheat varieties show moderate to high susceptibility to the Ug99 strain. \r\n\r\n ABARES estimated the potential economic impact of a Ug99 outbreak on the Australian wheat industry for three wheat growing areas. An outbreak in Western Australia is estimated to cost the wheat industry over a 10-year period a total of $567 million, an outbreak in south-eastern Australia $803 million and an Australia-wide outbreak $1,362 million. These costs were based on the assumption that Ug99 has entered, established and spread to the full extent for each outbreak scenario, and did not lead to trade bans by wheat importers. \r\n\r\n The study estimated significant benefits in continuing to invest in biosecurity prevention, ranging from $28 million to $70 million a year, depending on the extent of spread and whether or not trade bans were imposed by wheat importers. \r\n\r\n Ongoing research and development (R&D) to secure seed stocks of Ug99 resistant varieties plays an important role in reducing potential future industry losses. The wheat industry losses avoided by securing seed stocks of Ug99 resistant varieties, and switching to these varieties immediately following any future entry, is one example of the benefits that can be derived from past biosecurity R&D. \r\n\r\nKey Issues \r\n• Wheat stem rust has been present in Australia for over a century. \r\n• The most recent and severe outbreak of the disease in Australia was the 1973 epidemic. \r\n• Ug99 is a particularly damaging strain of the disease not present in Australia, but is a concern. \r\n• The severity of an outbreak depends largely on the extent of susceptible wheat varieties grown and suitability of climate to the fungal disease. \r\n• Around 30 per cent of Australian current wheat varieties show moderate to high susceptibility to the Ug99 strain. \r\n• Wheat varietal improvement has resulted in fewer wheat stem rust incidences since the major outbreak. \r\n• Governments and the industry should continue to invest in varietal improvements which provide resistance to emerging strains. \r\n概述 小麦茎锈病已在澳大利亚存在逾一个世纪。该国该病害最近一次且最为严重的暴发为1973年的流行事件。不过，该病害的高危害性菌株Ug99于1999年在乌干达被首次发现，目前尚未在澳大利亚出现，已成为主要防控关切点——澳大利亚当前约30%的小麦品种对Ug99菌株表现出中至高易感性。 澳大利亚农业与资源经济科学局（Australian Bureau of Agricultural and Resource Economics and Sciences，简称ABARES）针对三个小麦种植区域，评估了Ug99暴发对澳大利亚小麦产业的潜在经济影响。经估算，若暴发于西澳大利亚州，该国小麦产业在10年内的总损失将超过5.67亿澳元；若暴发于澳大利亚东南部地区，损失将达8.03亿澳元；若在全国范围内暴发，损失则高达13.62亿澳元。上述成本基于以下假设前提：Ug99已完成传入、定殖并在各暴发场景中实现全面扩散，且未引发小麦进口国实施贸易禁令。 该研究估算，持续投入生物安全（biosecurity）防控可获得显著收益，年收益区间为2800万至7000万澳元，具体收益规模取决于病害扩散范围及小麦进口国是否实施贸易禁令。 为保障抗Ug99小麦品种的种子储备而开展的持续研发（research and development，简称R&D）工作，对降低未来产业潜在损失具有重要意义。通过储备抗Ug99品种的种子并在未来病害传入后立即更换种植这些品种，可有效避免小麦产业损失，这正是过往生物安全研发可带来的收益之一。 核心议题 • 小麦茎锈病已在澳大利亚存在逾一个世纪。 • 澳大利亚该病害最近一次且最为严重的暴发为1973年的流行事件。 • Ug99是该病害的高危害性菌株，目前尚未在澳大利亚出现，已引发广泛担忧。 • 病害暴发的严重程度主要取决于种植的易感小麦品种占比，以及气候是否适宜该真菌病害的繁衍传播。 • 澳大利亚当前约30%的小麦品种对Ug99菌株表现出中至高易感性。 • 自该重大暴发事件以来，小麦品种改良已使小麦茎锈病的发生频次显著降低。 • 政府与产业界应持续投入品种改良工作，以培育对新兴致病菌株具有抗性的小麦品种。