A rice cultivar, Cas 209 (IRRI Accession 15793), responded differentially to strains of virulence group (VG) II of X. campestris pv. oryzae in the Phillipines indicating that VG II contains a mixture of strains that are either virulent (VG IIa) of virulent (VG IIb) to Cas 209. Strains of VG I, VG IIa, VG IIb, and VG III can be distinguished by their differential virulence on the rice differential cultivars IR8, IR20, Cas 209, IRI 1545-339 and DV85. The differential reactions were consistent for 2 inoculation methods and for inoculations at both early tillering and maximum tillering growth stages of rice. The results confirm the presence of pathogenic races of the rice bacterial blight pathogen in the Phillipines.