Plum pox show no symptoms on leaves or fruit. Not all infection in "Prunus" are characterized by a ring symptom on leaves. Several cultivars show yellowing line patterns and blotches, or necrotic ring symptoms on expanded leaves. Leaf distortion has also been observed. Infected fruit can develop yellow rings or blotches, or brown rings, and some plum and apricot fruit can be severely deformed and bumpy. The seed of many infected apricots and some plums show rings. Many non-"Prunus" species, in at least nine plant families, have been infected artificially with one or more strains of the plum pox virus, and in
Plum and early April in the United Kingdom. Fruits are usually of medium size, between 2 and 7 centimetres in diameter, globose to oval. The flesh is firm and juicy. The fruit's peel is smooth, with a natural waxy surface that adheres to the flesh. The plum is a drupe, meaning its fleshy fruit surrounds a single hard seed. Plum cultivars include: When it flowers in the early spring, a plum tree will be covered in blossoms, and in a good year approximately 50% of the flowers will be pollinated and become plums. Flowering starts after 80 growing degree days. The