7:07 pm - Thursday May 23, 2019

Contagious disease destroying Bangladesh wheat fields

Only desperate farmers would burn down their own fields before harvest. But, in Bangladesh, that’s exactly what wheat farmers are doing. They are trying to contain a devastating fungal infection, and their last option is to set fire to infected fields.

The infection, called wheat blast, was first detected in 1985 in Brazil. Since then, it has spread rapidly through South America. Its effects are so severe that many affected districts no longer grow wheat.

wheatCaused by fungus Magnaporthe oryzae, wheat blast has now reached Bangladesh. By one estimate, some 15,000 hectares of produce has been destroyed already. For the country’s 150 million people, wheat is the second major food source after rice.

We don’t know for certain how wheat blast got to Bangladesh. One way is that the strain mutated and jumped from another species to wheat. This has happened once before, when the fungal infection began spreading in the US in 2011.

A more likely way, going by early genetic analysis, is that wheat imported from Brazil brought the infection to Bangladesh. If true, this is worrying for other countries such as Thailand, Vietnam, and the Philippines, which import wheat from Brazil.

Wheat blast thrives in hot and humid climates. This means it could easily spread to other south and southeast Asian countries even if they don’t import Brazilian wheat. It is particularly worrying for India and Pakistan, researchers from the Bangladesh Agricultural Research Institute told Nature.

The US managed to control the spread of wheat blast in 2011 through surveillance and action. But that kind of surveillance is much harder in developing countries.

The other way to fight it is to create strains of wheat that are resistant to the infection. Last month, scientists at Kansas State University reported the first gene variant that provides some resistance against the fungus. However, to beat M. oryzae, researchers will need to find many gene variants and then incorporate those in wheat seeds.

To aid the process, scientists in the UK and Bangladesh have launched the Open Wheat Blast initiative. Anyone can download the genomic data of the Bangladesh strain of wheat blast. The initiative hopes that the Asian crisis will evoke a greater international effort to fight the disease.



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