The present invention provides methods to improve the health and vigor, including enhancement of the growth of plants, including important crop plants. In particular, the present invention provides methods of treating or preventing a rhizogenic or tumorigenic plant disease caused by bacteria, comprising administering to the plant an effective amount of at least one isolatedPaenibacillusstrain or of an extract of at least one isolatedPaenibacillusstrain, wherein said at least one Paenibacillus strain comprises a 16S rRNA sequence with at least 93% sequence identity to the sequence of SEQ ID NO: 1.
