Orange Tubes on Pear Fruit
Q: These pears are on a 30 year old hard pear tree. Approximately 80% of the fruit look this way. When the fruit were the size of a marble, they were deformed. After several weeks, they developed bright red bristles which shed spores which sometimes showed up on leaves below.
A: It’s either cedar-quince rust, Gymnosporangium clavipes, or cedar-hawthorn rust, Gymnosporangium globosum. Either one can have the orange/pink aecia (tubes) on fruit as well as on leaves and twigs.
Yellow spots on the leaves is a more typical symptom.
I’ve never seen aecia on apple fruit infected with the similar cedar-apple rust, Gymnosporangium juniperivirginianae.