In China, the species' range of P. xylostella can be
divided into three zones: the ‘year-round breeding region’ (YBR),
the ‘winter diapause region’ (WDR) and the ‘summer breeding region’
(SBR) (Fig. 1) (Wu, 2002). P. xylostella has continuous generations
in its YBR. In the WDR, it has 6e8 generations per year