Dark pericarp disease (DPD) in litchi is a physiological disease caused by excess manganese (Mn) in pericarp, impacting fruit appearance and marketability and leading to substantial economic loss. The susceptibility of litchi varieties to DPD differs greatly, but the underlying mechanisms remain vague. In this study, we investigated the discrepancies in physiological and biochemical processes in pericarp of two varieties (Feizixiao and Heiye) resistant to DPD and a susceptible cultivar (Guiwei) during fruit development from the same orchard. Pericarp Mn in Guiwei was significantly lower than that in Feizixiao and slightly higher than that in Heiye through fruit growth. Under Mn stress, Feizixiao and Heiye maintained ROS homeostasis, whereas substantial H