Rapid Detection of the Pathogenicity of Phytopathogenic Pseudomonads

Abstract

MOST bacterial plant diseases are caused by bacteria belonging to the genus Pseudomonas. A number of saprophytic pseudomonads occur in large amounts on the surface of the plant (Pseudomonas fluorescens, Ps. denitrificans, etc.). Therefore, isolation of phytopathogenic pseudomonads from the diseased plant is difficult. Generally the morphology of the colonies, the biochemical properties¹, the antigenic structure¹ and the phage sensitivity² of the pathogenic and saprophytic pseudomonads are so similar that they can scarcely be distinguished on the basis of the foregoing characteristics. In practice the pathogenicity test is the sole reliable method which can be used for identification. To carry out pathogenicity tests one must have suitable hosts, but in this case the entire procedure of artificial infection in the greenhouse is tedious. Testing of woody plants is particularly difficult.