Every year, BPH populations that propagated in Southeast Asia such as northern Vietnam and the Philippines migrate via south China and Taiwan to Japan in early summer45,46 and cannot overwinter in Japan. Therefore, the strains of BPH that migrate to Japan are affected by the resistant cultivars cultivated in Southeast Asia. Myint et al.11 reported that BPH26-NIL showed resistance to the BPH strain collected in Japan in 1989 (strain-Chikugo-89).