Citrus Black Spot is a fungal disease caused by the pathogen Guignardia citricarpa. It primarily affects citrus fruits, such as oranges, lemons, and grapefruits, leading to dark, sunken lesions on the fruit's surface. This disease can reduce the quality and marketability of the affected fruits. The disease thrives in warm, humid conditions and can spread through infected plant material or contaminated equipment. Effective management includes using resistant varieties, proper sanitation practices, and fungicide applications to control the spread of the fungus and protect citrus crops.