io6 DISEASES OF THE SWEET PEA 



several species were recorded but none 

 were stated to be parasites. 



Symptoms. At the first glance ChsBto- 

 mium root rot is difficult to tell from 

 Thielavia. Infected plants lose their 

 green color, become pale and yellow, and 

 cease growing. The root system is usu- 

 ally found wanting or partly destroyed. 

 The disease seems to be primarily a seed- 

 ling trouble. 



Pathogenicity. The fact that a pure 

 culture of Chcstomium spirochete was ob- 

 tained from numerous platings of dis- 

 eased material from two different states 

 at once led to the supposition that the or- 

 ganism was the cause of the disease. In- 

 oculations with pure cultures of the fun- 

 gus into healthy seedlings proved the 

 organism to be a weak parasite, favored 

 by an excess of moisture in the soil. 



The Fungus. The mycelium of the 



