Small purple-to-reddish spots on leaves that coalesce into large dead, upward-curling, scorched-looking areas; elongated purplish-brown streaks on petioles and flower/fruit stalks; tiny black fungal fruiting bodies (acervuli) visible with a hand lens.
Favorable conditions
•Warm temperatures (20-25°C) with 9+ hours of continuous leaf wetness
•Overwinters on infected leaves that survive the winter
•Older and middle-aged leaves are infected more easily than young ones