Botrytis Bud Rot (Stem Canker/Rot), Gray Mold: Caused by Botrytis cinerea, this disease is characterized by gray, fuzzy fungal growth, typically appearing on succulent or necrotic tissue. It is more common in cool, wet, conditions (relative humidity >85%). This disease is most prevalent in the northern United States, Canada, and poorly ventilated greenhouses, as it thrives in cool temperatures and high–moisture environments.Airborne spores infect above–ground plant parts, leading to damping off, leaf or tip blight, and dense flower or grain head colonization. The fungus opportunistically colonizes damaged or necrotic tissue, often serving as the starting point for outbreaks.Botrytis cinereahas a broad host range