Why is false smut called harvest disease?

False smut is a disease of rice at heading stage caused by green sclerotia, also known as false smut, green smut, false smut, green smut, black smut and so on. This disease is a fungal disease, which often occurs in rice harvest years. Farmers mistakenly think that it is a sign of a bumper harvest, so it is commonly known as "bumper harvest disease".