348 



BULLETIN No. 189 



[June, 



EXPERIMENT 4: INOCULATION OF YOUNG CARNATION PLANTS WITH 

 ISOLATED AND WITH REISOLATED STRAINS OF RHIZOCTONIA 



The object of Experiment 4 was to compare the virulence of various 

 strains of Rhizoctonia when they were inoculated on carnation plants 

 for the first time, and after they had been inoculated" on carnation 

 and reisolated. Fifteen strains, taken at random, and about 300 plants 

 were used. 



On December 12, 1912, a number.of carnation cuttings were made 

 and placed in sterilized sand. They were allowed to remain in the 

 sand until well rooted. On March 22, when the plants were from 

 four to six inches high and breaking nicely, they were placed in three- 

 inch pots in sterilized soil. They were then inoculated by placing a 

 bit of bean pod infected with Rhizoctonia near the stem just below the 

 surface of the soil. Table 6 gives the results obtained. 



With seven strains the virulence of the reisolated fungus was 

 slightly greater than that of the original isolation. With two it was 

 slightly less. 



TABLE 6. COMPARATIVE VIRULENCE OF ISOLATED AND REISOLATED STRAINS OF 

 RHIZOCTONIA WHEN INOCULATED ON YOUNG CARNATION PLANTS (IN POTS) : 



EXPERIMENT 4 



EXPERIMENT 5: INOCULATION OF OLD CARNATION PLANTS IN THE 

 BENCH WITH VARIOUS STRAINS OF RHIZOCTONIA 



Experiment 5 was similar to the preceding experiment except that 

 the carnation plants used were older and were grown in the bench in- 

 stead of in pots, and that inoculations were made with only eight 

 strains of Rhizoctonia, chosen at random. 



