1. Hypoxia: The lack of oxygen inside the persimmon will lead to the persimmon turning black, which usually happens when the persimmon is picked and stored improperly.

2. Diseases: Black lumps of persimmons are caused by diseases, such as anthracnose and scab. These diseases will cause persimmon fruit to turn black, which will affect the taste and quality.

3. Pests: The black spots inside persimmons are caused by pests, such as persimmon moths and scale insects. These pests will lay eggs inside persimmons, and the hatched larvae will destroy the pulp of persimmons, leading to the appearance of black blocks.