A New Race of Spinach Downy Mildew in Japan

Appearance of race Pfs:5 of spinach downy mildew fungus, Peronospora farinosa f. sp. spinaciae, in Japan

“…In Japan, Shimazaki (1990) and Ozaki and Takahashi (1993) reported race 4 and resistant cultivars. In 2000, Satou et al (2002) discovered another race, although they could not determine it because it was impossible to compare it with those described by Correll et al (1998) and Nali (1998). As a result, Satou et al (2002) Spinach cultivars.…”

“…In 2000, Satou et al (2002) discovered another race, although they could not determine it because it was impossible to compare it with those described by Correll et al (1998) and Nali (1998). As a result, Satou et al (2002) Spinach cultivars. Nine Japanese cultivars and 12 of the 14 ISF differentials were tested against the three Japanese isolates (Table 1).…”

First report of spinach downy mildew caused by race Pfs:8 of Peronospora farinosa f. sp. spinaciae in Japan

“…The occurrence of new races is, however, on the rise in many parts of the world (Correll et al 2009). In Japan, Shimazaki (1988Shimazaki ( , 1990 reported races 3 and 4, and Satou et al (2002Satou et al ( , 2006 identified race Pfs:5 and another race similar to Pfs:6 or Pfs:7. The development of a new race in spinach-producing areas, especially from autumn to spring, needs special attention.…”

“…reaction on individual cotyledons; and nt, not tested in cv. Okame, susceptible to Pfs(Satou et al 2002(Satou et al , 2006; cv. Vision, resistant to races 1-7 of Pfs indicated in the catalog of…”

“…However, they were much less virulent on cv. Okame, which is regarded as susceptible to Pfs in Japan (Satou et al 2002(Satou et al , 2006 (Table 1). These results might indicate that this new pathogenic strain is not derived from the Pfs discovered in Japan in the past, but might have originated during the production of certain spinach cultivars that lack the unknown resistance gene(s) in cv.…”