The suppressive activity of 24 isolates of Paenibacillus against 6 isolates of Xcc was examined in the first dual culture assay using two different media (PDA and YDCA). By comparing the mean suppressive activity of 14 Paenibacillus isolates against Xcc, it was determined that there were no significant differences between the two different media (Table 2.3) and thereafter the results for both media were combined.