Rice Blast, Magnaporthe oryzae

by Grant Hodge, Sustainable Plant Systems majior

Rice Blast is a fungal disease of rice that causes brown lesions on the leaves. Rice blast is responsible for huge yield losses which affect millions of people world-wide. The lesions are diamond shaped and affect the ability of the plant to produce its maximum potential of seed. This disease is intensely studied around the world and damages the economies of rice-growing countries.

What does it look like?

A sign of rice blast is the diamond shaped lesions which can be found on all parts of the plant including the seeds.

What do we know?

There is lots of research currently being done on this particular disease and so there is lots of information out there on it. Rice blast is an ascomycete disease and has a pretty complicated disease cycle which is one of the reasons that this disease is so difficult to control. Rice blast can reproduce sexually and asexually so successful control options may be specific to each case.


To manage this disease requires a complicated series of control measures for successful control. Most of this control is standard for the majority of diseases such as crop rotation, ensuring proper fertility, and planting disease free, clean seed. One unique management strategy is to make sure that the water level is maintained at the proper height so the rice plants are not stressed and are less susceptible to the disease. Now with genetic engineering there are not resistant cultivars of rice that have had great success at preventing the presence of the disease in the field. If the disease cannot be prevented and an outbreak occurs, there are fungicides that can be sprayed to keep the disease under control and protect the quantity and the quality of the rice being produced. This disease can be managed it just requires a lot of work and knowledge to be successful at it.

This blog post was an assignment for Societal Issues: Pesticides, Alternatives and the Environment (PLNTPTH 4597). The views expressed are those of the author and do not necessarily reflect the views of the class, Department of Plant Pathology or the instructor.

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