Long-term Control of the Mulberry Scale, Pseudaulacaspis pentagona (Targioni), in Tea Fields by Spraying Pyriproxyfen in Winter

Abstract

We examined the long-term control of the mulberry scale, Pseudaulacaspis pentagona (Targioni), in a tea field by spraying pyriproxyfen in winter and determining the effects of spray timing, spray volume, and a combination of medium pruning and spraying. We obtained the following results: (1) the insecticidal activity persisted for approximately 5 months after spraying, (2) no difference was observed in the control effect when pyriproxyfen was sprayed in late January or in late March, (3) the amount of vermination decreased for 3 years when pyriproxyfen spray was combined with medium pruning in the following year, and (4) a similar control effect was observed in the application rates of 1000 L/10 a and 700 L/10 a. Moreover, spraying of pyriproxyfen resulted in the effective control of P. pentagona density for 2 years at all the examinations. These results indicate that when sprayed in winter, pyriproxyfen can serve as an important control agent of the mulberry scale. Because winter is the agricultural off-season for tea farming, it is possible to save on the cost of labor. In addition, the spray frequency of the insecticide can be reduced after achieving long-term density control.