Pseudomonas chlororaphis strain Sm3, bacterial antagonist of Pratylenchus penetrans

The interaction of Pseudomonas chlororaphis strain Sm3 and the root-lesion nematode Pratylenchus penetrans was investigated in three separate greenhou se experiments with soils from southern British Columbia, Canada. The bacte ria were applied to the roots of strawberry plants and planted in unpasteur ized field seas, with natural or supplemented infestation of P. penetrans. Nematode suppression in roots was evident after 6 or 10 weeks in all experi ments. Root or shoot growth were increased after 10 weeks in two experiment s. Population dynamics of P. chlororaphis Sm3 in the rhizosphere was follow ed using an antibiotic-resistant mutant of P. chlororaphis Sm3. There was n o apparent correlation between bacterial density in the rhizosphere and P. penetrans suppression in strawberry roots and rhizosphere soil, although th e soil with the highest nematode reduction also had the largest P. chlorora phis Sm3 population in the rhizosphere.