Witch's Broom is a fungal disease caused by various species of fungi, primarily from the genus Taphrina. It affects trees, particularly willows, oaks, and maples, causing abnormal growths or galls on branches. These galls can appear as dense clusters of twigs or leaves, resembling a broom, hence the name. The disease often results in stunted growth and can weaken the affected trees, making them more susceptible to other pests and diseases. Management typically involves pruning infected branches and maintaining tree health through proper care and monitoring for signs of infection.