

[Vol. 2 



438 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



fected, and through the sunken areas of these the hyphae 

 penetrated the seed and produced small sclerotia on the seed- 

 coats. The fungus was cultivated and typical Rhizoctonia 

 hyphae and sclerotia were obtained. Fulton ('08) observed 

 the disease in Louisiana on stems and pods, with the char- 

 acteristic ulcerations, especially at the surface of the soil or 

 just below. He proved the causal relation of the organism 

 through cultures, and inoculations yielded positive results 

 with the damping off of seedlings. McCready ('10) reported 

 the bean disease as new to Ontario, where it was also char- 

 acterized by stem and pod ulcers. In New York Barrus ('10) 

 observed an epidemic of this host in which as many as 30 

 per cent of the plants were affected. He determined the 

 fungus by cultural studies and proved its pathogenicity by 

 inoculation. On the sweet-pea the disease is mainly a root 

 rot, yet the base of the stem may also be considerably affected 

 before the plant succumbs. On the violet it is primarily a 

 crown disease, but where the plants are succulent and the con- 

 ditions are moist, the leaves are considerably invaded. 



FRUIT AND LEAF INJURIES 



In discussing stem diseases the occurrence of Rhizoctonia 

 on bean pods has been mentioned. Another case of fruit 

 injury is described by Wolf ('14), who found a severe rot of 

 egg plant fruits from which the fungus was obtained. The 



pathogenicity of the organism was determined by inocula- 

 tions, and cross inoculation from tomato and potato led to 

 the conviction that the organism was Rhizoctonia Solani. 



Direct attacks of leaves by Rhizoctonia Solani are infre- 

 quent. From the habits of the fungus this would be expected. 

 The one serious leaf disease reported is that of lettuce (Stone 

 and Smith, '00), in which the fungus spreads over the whole 

 surface, causing a moist rot. Sclerotia are frequently formed 

 in connection with this affection. It would be anticipated, 

 perhaps, that diseases of a similar nature might be found on 

 other plants with the rosette habit. Leaf stalks are fre- 

 quently invaded, or may be the regions of first attack, in the 

 case of the beet disease. The disease of leaf stalks of rhubarb 



