Plan in north to nip worst rice disease
From the May 2006 edition of Agriculture Today.
An initiative linking local and international researchers aims to protect Australia’s $800 million rice industry from the world’s worst rice disease - rice blast.
NSW Department of Primary Industries scientists are taking an approach to ensure that the only region in the world free of rice blast, South East Australia’s rice-growing area, is not endangered by the fungus that spreads the devastating disease.
NSW DPI research scientist, Ric Cother, said the project aimed to determine what risk rice blast posed to the industry and develop strategies to address the risk, including the breeding of resistant rice varieties.
'Rice blast is caused by the fungus Magnaporthe grisea, commonly found in South East Asia and we’re working closely with our northern neighbours to survey for its presence,' Dr Cother said.
'Fungus spores are wind-borne and could be easily carried by monsoonal winds or normal air currents from northern areas to southern rice crops in NSW and Victoria.
'Not all strains of the fungus cause rice blast disease and at this stage we need to work out what strains are present in areas which could impact on the local rice industry.
'Rice blast has occurred in Queensland and the Northern Territory and we are taking samples of wild rice in those areas to determine if the strains of the fungus present there will affect rice varieties commonly grown in Australia.
'Because we’ve been fortunate enough to have avoided an outbreak of rice blast in the past we don’t know how well local varieties will deal with the disease.
'Once we identify the various strains of the fungus we’ll be able to work out how susceptible or resistant our rice varieties are,' he said.
The disease, which can affect rice plants at all growth stages, attacks the stems, leaves and emerging rice grains resulting in yield loss.
The Australian rice biosecurity plan recently classified rice blast as the highest exotic disease threat to the industry.
While a diagnostic and contingency plan is in place to cope with an outbreak, significant economic losses are predicted should rice blast take hold.
According to Dr Cother NSW has much to learn from the Californian rice industry which had been free of rice blast until 1996 when it was devastated by the disease.
'A fungus strain introduced from Japan reduced their yields by 15 to 30 percent after infecting an initial 12 000 acres which spread to 100 000 acres and is continuing to expand.
'Given the trading relations we have with Japan, tourism and farmer visits to inspect crops in both countries, plus research which has estimated that 240 000 fungus spores were brought into Australia in 1998 alone, make this an important and timely project,' he said.
Southern Cross University (SCU) expertise in molecular science will be used to develop rice DNA markers to target resistant and susceptible varieties.
Earlier this month Dr Cother surveyed the far north of the Northern Territory, including the Kakadu National Park, and he now plans to survey areas of Cape York Peninsula for the fungus.
'In 2007 we plan to complete surveys in Cape York Peninsula, NT and East Timor before the release of our final report in November that year.'
The project is funded by the Rural Industries Research and Development Corporation through the CRC for National Plant Biosecurity. NSW DPI collaborators include scientists in France and the US, SCU, Charles Sturt and Charles Darwin universities, Australian Quarantine Inspection Service and the Northern Australian Quarantine Service.
Contact: Dr Ric Cother, Orange, 02 6391 3800.