Early fall of persimmon (Diospyrus kaki L.) fruits, of the Fuyu variety, is an important problem in São Paulo State and seems to be partially related to a heavy infestation of the mite Aceria diospyri K. (Acarina: Eriophyidae) which lives under the fruit buttons. The rôle of the mite in the fruit fall was investigated through its control using Sevin 85 PM. Three spraying with monthly interval, beginning after petal fall, at the dosage of 2g/l, produced an absolute control of the mites and increased the fruit setting of the Fuyu variety by 16%, 10% and 25% in the 1967/68, 1968/69 and 1969/70 crop season, respectively.