Senescent scald, also known as common scald, is a physiological disease that produces a brown to black discoloration of the skin of Bartlett, Bosc, and other varieties of pears (see photo). It is associated with fruits that have turned color in storage and have lost their capacity to ripen normally. Initially the discoloration is entirely superficial, but it progresses rapidly into the flesh at moderate or high temperatures. In late stages the skin weakens and sloughs off readily. Decay may follow as a secondary disease.
The taste and odor of affected fruits are characteristically disagreeable and sickening, even before discoloration appears. The disorder is more severe on immature fruits than on mature fruits, a characteristic it shares with ordinary scald of apples. Unlike apple scald, however, this disease is not controlled by oiled paper wraps.
Control measures.-Since disease development is favored by higher temperatures than those recommended, fruits of optimum maturity for long storage should be stored promptly, cooled quickly, and maintained at a temperature range of 30 to 31 °F.
Pear senescent scald