50 EXPERIMENT STATION. [Jan. 



A Disease of the Kadish. 



BY G. E. STONE. 



A greenhouse disease of the radish, caused bj a fungus 

 {Ascocliyta sp.), has been brought to our attention a few times. 

 In one instance a large number of plants were affected. The 

 fungus attacks the young plants, in some instances quite se- 

 verely, and the same fungus is known to cause injury to seed- 

 lings. 



We are unable to find any reference to this fungus occurring 

 on the radish, neither does Saccardo give the radish as a host 

 for any of this genus. It may, therefore, be an nndescribed one, 

 although we have not attempted to compare it with sjDecies af- 

 fecting other plants. 



For the purpose of determining whether this infection came 

 through the soil, or whether the seeds were responsible for it, 

 experiments were made at our station by Mr. A. Y. Osmun 

 and ]\Ir. Ealph Watts, who were working in the station labora- 

 tory at that time, with the following results : — 



One box of soil was taken from the infected house and planted 

 with seeds from the same lot as those used for the infected 

 house. Itesult, all plants diseased. 



One box of soil from the infected house, sterilized, was 

 planted with seeds taken from the same lot as those used f(jr 

 the infected house. Result, only one plant infected. 



The same experiment repeated. Result, no diseased plants. 



One box of soil taken from the infected house and planted 

 with experiment station seeds. Result, plants infected. 



One box of experiment station soil planted with seeds taken 

 from the same lot as those used in the infected house. Result, 

 no infection. 



From these experiments it is evident that the disease germs 

 were in the soil and not associated with the seed, and that 



