At the earliest stages of development, bitter pit lesions, which usually occur near the fruit's calyx,
start as small, water-soaked spots on the skin. These spots gradually turn a deeper color than the surrounding
fruit surface and, as the tissue underneath dies, they turn brown. Shallow, dark brown areas are present
beneath these spots and resemble small bruises. With time the spots become slightly sunken, and the underlying
dark brown tissue dries and becomes spongy. Generally symptoms do not fully develop until after 1 or
2 months of storage.
Bitter pit is related to low calcium levels in fruit, but is not usually directly related to the amount
of calcium applied. Cultural practices can influence calcium availability to fruit, but no practice completely
prevents bitter pit symptoms. Maintain a constant soil moisture supply. Reducing excessive vegetative
growth without overpruning can reduce bitter pit. Early thinning or overthinning may increase its incidence.
Overfertilizing or harvesting too early may cause symptoms to increase. Some cultivars are less susceptible than others to bitter pit.