Abstract
In the present paper the writers described the result of experiments on the pathogenicity of Pellicularia filamentosa to cucumber seedlings, and on some characters on culture media of thirty eight isolates obtained from many different host plants.
The pathogenicity of this fungus to cucumber seedlings is generally intensive in the isolates obtained from seedlings. Generally, the isolates with no pathogenicity showed a poor mycelial growth, while pathogenic ones showed rapid growth of mycelium as much as 8∼11mmper 5hrs. The isolates of sasakii-type were found in the isolates with more rapid growth of mycelium. As carbon sources of this fungus, hexose was more available than pentose. It seems, however, that the isolates of sasakii-type having a weak pathogenicity represent a poor utilization of maltose. The isolates which were able to utilize rhamnose seemed to have a pathogenicity. However, the isolates which were not able to utilize much of phenylalanine did not utilize also much of both histidine and tryptophan, nor one of them in excess. Moreover, the isolates showing a poor utilization of urea and cysteine seemed to belong to the sasakii-type. Although both solani- and sasakii-type have many different characters, they are not divided so distinctly into two groups, solani- and sasakii-types, and intermediate types are found.
