Stony Pit of Pear Fruit Pathology Penn State Department of Plant Pathology Jim Travis, Jo Rytter and Ken Hickey Stony Pit of Pear Stony pit of pear is presumed to be caused by a destructive virus, however, the virus has not been isolated.
Affected fruit are unsightly and unmarketable.
Symptoms Symptoms begin as early as three weeks after petal fall, when dark green areas form on the fruit. Cell growth surrounding these areas is restricted, and as a result, fruit become pitted, gnarled and deformed. Pits are produced by others causes such as plant bug injury, mechanical damage, boron deficiency or cork spot. However, pits caused by such factors are more superficial. Heavily pitted fruit may become so gritty that it is difficult to cut the fruit with a knife.