Rice False Smut: An Increasing Threat to Grain Yield and Quality

Abstract

Rice false smut (RFS) is the most important grain disease in rice production worldwide. Its epidemics not only lead to yield loss but also reduce grain quality because of multiple mycotoxins generated by the causative pathogen, Villosiclava virens (anamorph: Ustilaginoidea virens). The pathogen infects developing spikelets and specifically converts individual grain into a RFS ball that is established from mycelia covered with powdery chlamydospores, sometimes generating sclerotia. RFS balls seem to be randomly formed in some grains on a panicle of a plant in the paddy field. However, epidemics differ largely among varieties, fields, and seasons. This chapter introduces current understanding on the disease, mycotoxins, the biology of the pathogen, pathogenesis of RFS, rice resistance, the disease cycle, the disease control, and assay.