120 REPORT OF THE BOTANIST OF THD 
PARASITISM OF THE FUNGUS. 
In many cases Rhizoctonia is truly parasitic, and there can be 
no question about its being the cause of the diseases with which 
it is associated. The diseases of beet, carnation, lettuce, and 
some others with which we have experimented may be readily 
induced by merely placing in contact with the plant pure cultures 
of the fungus; and in time infection will result, provided there 
is sufficient moisture. Infection results more readily with the 
carnation by direct insertion of bits of the fungus into the plant. 
In other cases where the fungus is associated with disease, we 
have as yet no proof that Rhizoctonia is the chief or even partial 
cause of the trouble. It may sometimes be associated with other 
fungi, perhaps Fusarium. Atkinson! has indicated that the 
sterile damping-off fungus of cotton may perhaps have a part to 
play in the Fusarium disease of cotton, at least in initiating the 
disease. | 
In spite of the fact that Rhizoctonia is at times an effective 
parasite, the fungus is probably capable of protracted existence 
upon decaying organic matter in the soil. In this way it may 
be able to propagate itself, and to spread from plant to plant in 
the soil even when culture or other means fail to disseminate it. 
In fact, it seems to be of very general occurrence in the soil, and 
is likely to be quite commonly found in propagating beds as a 
cause of damping-off among cuttings and seedlings. From our 
experience thus far, we venture to predict that few forms of this 
fungus will be found very selective as to host, and one may well 
search for it upon the common weeds. The occurrence of this 
fungus as a disease producing organism is largely dependent upon 
the conditions, and when by excess of moisture or of heat the 
plant is placed at a disadvantage, or the fungus favored, the dis- 
ease is likely to occur. | 

“Atkinson, Geo. F.; Some Diseases of Cotton. Ala. Agr. Dxp., Sta., Bul- 
letin 41, p. 28. 
