Botrytis cinerea lesion at the tip of a poinsettia bract. Botrytis cinerea sporulation on poinsettia flower parts. Colored petals show rings of intensified color around the lesions. The petioles and flower stalks developing beneath the canopy may become infected and rot, causing portions of the plant to collapse. Subsequently, the infected petioles and pedicels typically become covered with grayish brown B. cinerea sporulation.
Young seedlings are susceptible to damping-off.
Initially, a stem canker on exacum caused by B. cinerea has a water-soaked appearance and may be bordered by a white halo. Both B. cinerea and INSV cause pale tan cankers on the secondary stems. Leaves infected with B. cinerea develop tan spots approximately 3 mm in diameter or bleaching or necrosis of the leaf margin. Lesions may coalesce to form large, tan, zonate, membranous lesions. Infected flowers exhibit water-soaked flecking on the petals or may become completely colonized and then collapse and turn brown.