Researchers identified a fungus called Pseudocercospora mori as the cause of grey leaf spot disease in mulberry trees grown in Guangdong Province, China. Using advanced DNA sequencing and traditional microscopy, they confirmed this pathogen causes dark spots on mulberry leaves that reduce quality and yield, harming the silk industry that relies on mulberry leaves to feed silkworms. The study developed specific detection methods to help farmers identify and manage this disease in their orchards.