326 BULLETIN No. 189 [June, 



material showed the causal organism to be R. Solani. The plants were 

 bushy, so that some of the branches and leaves were in contact with 

 the soil. The symptoms and appearance of the disease were similar 

 to those described for Dianthus. 



LAMB'S QUARTERS, Chenopodium album 



During the summer of 1913 several wilted Chenopodium plants 

 were observed along the border of the old herbaceous grounds of the 

 Station. On pulling up the wilted ptants, it was found that R. Solani 

 was the cause of the wilting. The fungus did not enter very deep 

 into the tissues, but rather girdled the stem and formed a scurfy layer. 



Duggar and Stewart 32 in 1901 reported the occurrence of Rhizoc- 

 tonia on Clienopodium album. 



Lavatera arborea variegata 



During March, 1913, in the floricultural greenhouses, a number of 

 seedlings in small seed pans, among which were several pans of Lava- 

 tera, began to damp off in a manner characteristic of R. Solani. 

 Pure cultures of diseased seedlings yielded this fungus. Strands of 

 the brown mycelium could be seen on the surface of the soil and 

 extending up on the stems and leaves. This was noticed again in the 

 spring of 1914. 



LETTUCE, Lactuca sativa 



Atkinson 4 in 1895 mentioned the damping-off of seedling lettuce, 

 among a number of other plants, by a sterile mycelium which later 

 proved to be Rhizoctonia. 



Stone and Smith 128 found that R. Solani caused a rot of green- 

 house lettuce, altho the disease was not common. The first appearance 

 was on the lower leaves where they lay on the ground ; a brown rot 

 set in, which spread thru the leaf in a very characteristic manner. 

 The green blade rapidly rotted away, leaving the midrib and stalk as 

 sound as tho the blade had been carefully cut away or had been eaten 

 by insects. 



Duggar and Stewart 32 observed the damping-off of lettuce seed- 

 lings by Rhizoctonia for a number of years. They found that at or 

 near the surface of the ground the tissues become water-soaked in 

 appearance and unable longer to support the seedling, so that it falls 

 to the ground, the fungus invading all parts. Within a day or two 

 this fungus, under favorable conditions, wilted down and destroyed 

 whole boxes of lettuce seedlings. Duggar and Stewart also observed 

 several times what was apparently the same fungus causing a disease 

 of mature lettuce plants. On the older leaves the leaf blades alone 

 were affected, but the more delicate inner leaves succumbed entirely, 

 blackening and decaying with the progress of the disease. 



