Seasonal change of the rate of viruliferous winged aphids in the areas of Aichi Prefecture where ringspot disease is occurring among Japanese apricots. Tree and Forest Health 22 : 147~151 Plum pox virus (PPV), the pathogen of Ringspot disease of Japanese apricot, is transmitted by aphids. To identify the periods suitable for controlling aphids, we investigated the seasonal change of the rate of viruliferous winged-aphids in the area, Inuyama City, Aichi Prefecture where the Ringspot disease of

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... apanese apricot is occurring, between March 2015 and March 2016. As a result, it is found that the ratio of PPV-positive aphids was high in spring and autumn and low in summer and winter. Genetic analysis showed that group of PPV-positive aphids contain several species, including Aphis spiraecola and A. gossipy which are known to transmit PPV. Our results suggest that it is important to control winged-aphids in spring and fall in order to prevent of spread of PPV in this area.