Planning the fight against wheat blast

Planning the fight against deadly fungal disease wheat blast

ANU researcher Peter Solomon inspects Australian wheat varieties for symptoms of the disease wheat blast.

ANU researcher Peter Solomon inspects Australian wheat varieties for symptoms of the disease wheat blast.


Wheat blast is a disease that strikes fear into farmers across globe - testing has found there is some resistance in Australian wheat lines.


RESEARCHERS from the Australian National University (ANU) have modelled how Australian wheat crops would cope if a destructive disease that's yet to hit our shores ever made it into the country.

Wheat blast is yet to make it to Australia, but has caused significant damage to crops in locations such as South America and subcontinental Asia since it was first discovered in the 1980s.

Brazil and Bangladesh have both reported virtual 100 per cent crop in parts as a result of the disease, which thrives on moist and warm conditions.

There is no dedicated breeding for wheat blast, caused by a fungal pathogen, resistance in Australia as it is not found here.

An ANU team, led by Peter Solomon from the ANU Research School of Biology tested 20 Australian wheat varieties, to see how they'd stand up to the disease.

While 16 Australian wheat varieties were significantly affected, four survived.

Professor Solomon says this is encouraging considering the impact wheat blast has had on crops overseas.

"It can be absolutely devastating under the right conditions - when it's hot and humid, we're talking about 100 per cent loses," he said.

In good news for Australian growers, Prof Solomon said our drier environments were generally less conducive to wheat blast, but warned this did not rule out the threat of an outbreak here.

And he said the seriousness of the disease was something Australian growers rarely saw.

"Most of the diseases we deal with here in Australia you're looking at more like 10-15 per cent loses, and they can typically be controlled by existing practices such as growing resistant varieties or using fungicides.

"But conventional approaches haven't been effective in controlling wheat blast, and once symptoms of the disease first appear, it can wipe out an entire crop in around 10 days.

"Unfortunately once the disease is established, growers often have to burn the crop to the ground to reduce the risk of it spreading."

In terms of diseases, wheat blast is a new threat.

It first showed up in 1984, and is primarily found in South America and more recently Bangladesh, highlighting that it is very mobile.

"The disease showed up in Bangladesh about three to four years ago, which means it nearly has a land bridge to Australia," Professor Solomon said.

"Crops typically only evolve resistance to a disease if they're exposed to it - kind of like humans developing resistance to a strain of the flu.

"Our crops have obviously never seen this fungus before, so the Australian wheat industry is concerned about what will happen if this thing ever gets here."

Professor Solomon says if wheat blast did ever arrive in Australia, it would have a significant financial impact.

"What a lot of people don't realise is that we export around $5 billion a year in wheat, it's in the top 10 export earners for the Australian economy," he said.

"Of that we lose 10-15 per cent of it to diseases, and they're ones we can manage; the ones we know how to deal with.

"At least we now know that some of our top cultivars have got some sort of resistance to wheat blast."

In order to carry out the tests, the researchers had to get the seed all the way to Bolivia, a wheat blast 'hotspot'.

"In this particular case the disease was there, it was quite strong, so it gave us a really good indication of which cultivars hold up and which ones wouldn't," Professor Solomon said.

It's hoped this information will help not only Australian farmers, but growers in Bangladesh and South America as well.

The study was carried out in collaboration with investment from the Grains Research & Development Corporation.


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