by Elizabeth Kifer – Professional Golf Management Major
Rice is one of Asia’s main food staples and in 1942 it had almost disappeared. The area of Bengal in West India had experienced a disease that reduced rice yield to 40-90% and an estimated 3 million people died from starvation. According to the Crop Life Foundation, “nothing as devastating as the Bengal rice brown spot epidemic of 1942 has been recorded in plant pathology literature.”
This widely underrated disease is Cochliobolus miyabeanus (croplife.org) or simply known as brown spot. It is a fungal disease that attacks the plant’s coleoptile, leaves, leaf sheath, panicle branches, glumes and spikelets. It looks like brown spots on the leaves and can kill the whole leaf. The disease develops in hot temperatures and in un-flooded and nutrient-deficient soil, or in soils that accumulate toxic substances. The leaves must be wet for 8-24 hours in order for infection to occur. Most shockingly, the disease can survive in the seed for more than four years! It spreads through air and be in weeds, infected rice debris, and infected seed. According to Rice Knowledge Bank, “Brown spot can occur at all crop stages, but infection is most critical during maximum tillering up to the ripening stages of the crop.”
Luckily, we can prevent the spread of brown spot by regularly checking for lesions, planting resistant varieties, and monitoring soil nutrients regularly.
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.