Cercospora leaf blight and purple seed stain of soybean: A permanent challenge

Cercospora leaf blight (CLB) and purple seed stain (PSS) are major diseases of soybean responsible for significant yield loss. These diseases are caused by Cercospora species, such as C. kikuchii and C. cf. flagellaris, among the main species. These pathogens overwinter in infested debris and infected seed. Due to the combination of no-till farming, monoculture in large soybean cultivation areas and climate changes, these diseases have become serious and prevalent. At present, in addition to the practice of monoculture soybean cultivation, there is a lack of soybean varieties with genetic resistance to these diseases. As a result, the application of fungicides becomes an essential tool for effectively managing this pathosystem. However, in the main soybean-producing countries, resistance to quinone outside inhibitors and benzimidazole fungicides has already been studied and documented. Furthermore, Cercospora spp. are believed to be naturally insensitive to succinate dehydrogenase inhibitors. Consequently, there is a growing interest in innovative and integrated tools for managing crop diseases. These new approaches include the use of biofungicides, biostimulants and plant defence inducers. Research testing new management tools in a complementary and integrated approach involves a short-term challenge to improve CLB/PSS management in the field. This review provides comprehensive details on the taxonomy, identification and genetic diversity of the pathogen, its disease symptoms and host range. Additionally, it outlines epidemiological aspects, fungicide resistance and the latest advancements in tools and technologies, aiming to guide future research and strategies to address the escalating threat to soybean crops globally.