Paenibacillus spp. isolates tested in this study differed in their ability to suppress the
growth of Xcc isolates in vitro. Differences in the genetic backgrounds of the Paenibacillus
spp. isolates are likely to have contributed to this variation. The 24 Paenibacillus spp. isolates represented 11 different species of which six displayed activity against Xcc in the
present study. Even among species, there was considerable variation in the bioactivity
of the isolates, which was in accordance with a study by Phi et al. (2010). Xcc isolates
may also vary in their level of sensitivity to the Paenibacillus spp. isolates. However, the
genetic diversity of the Xcc isolates used in this study was not investigated and more
studies need to be done on the pathogenic variation of Xcc isolates in the biological
control research.