In this study the biocontrol activity of 25 isolates of Paenibacillus isolated from New Zealand produced cabbage and forage rape seed lots was tested against Xcc in dual culture experiments in vitro and in growth chamber experiments based on pot trials. The Paenibacillus isolate with the greatest biocontrol activity against Xcc was selected based on the pot trial studies, and the effect of this Paenibacillus isolate on the growth of cabbage plants was then examined.