WSU Tree Fruit Research & Extension Center

Tree Fruit Market Diseases

Sunday, February 17, 2019

WSU-TFREC/Postharvest Information Network/Tree Fruit Market Diseases/pearblackrot

Physialospora obtusa (Schw.) Cke.

Black rot occurs on Eastern-grown pears but is not important in properly sprayed orchards. The disease is caused by the same organism that causes black rot of apples and quinces (see Apples, Black Rot). Black rot follows the same distribution and course of development on pears that it does on apples but is not as important on pears. Fruits, leaves, and branches may be attacked. On fruits the rot is firm and brown to dark brown (see photo). Concentric zones of light and dark brown may or may not be present. Small, black fungal fruiting bodies (pycnidia) may dot the surface of advanced rots in the orchard but are seldom found in cold-stored fruits.

Control measures are identical to those for black rot of apples. Consult your State agricultural experiment station or extension service to control the disease in the orchard.

Black rot on pear
Black rot on pear

Tree Fruit Research & Extension Center, 1100 N Western Ave, Washington State University, Wenatchee WA 98801, 509-663-8181, Contact Us