Petroleum oil emulsifiable concentrate (POEC) is a commercial acaricide used for the control of Tetranychus kanzawai Kishida in the autumn/winter season. Further, the damage of bacterial shoot blight increases if POEC is sprayed at this time of the year. It is thought that the occurrence of bacterial shoot blight doesn't increase if POEC is sprayed just before the sprouting of the first crop of tea. However, it is suspected that spraying of POEC at this time results in the formation of an oily

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... ilm that floats on the surface of tea infusion. In this study, we examined the efficiency of spraying POEC at this time of the year in controlling the growth of T. kanzawai and Acaphylla theavagrans Kadono and the residual effect. We obtained the following results: (1) spraying POEC before sprouting of the first crop of tea resulted in effective control of the density of T. kanzawai and A. theavagrans for 1 month or longer, and (2) the oily film was not observed on the surface of the tea infusion. These results indicate that POEC can ser ve as one of the important control agents of mites when sprayed just before the sprouting of the first crop of tea.