The Sterile Fungus Ehizoctonia. 65 



of the Cornel) Experiment Station. In December, 1898, the 

 writers presented a paper on Rhizoctonia to the Society for Plant 

 Morphology and Physiology at its meeting in New York City. 

 This paper, which was entitled " Different Types of Plant Diseases 

 dne to a common UldzoGtonla^'' was puhlished only in abstract." 

 During the ])ast year Stone and Smithf have published an account 

 of lettuce lihizoetonia, and some experiments on its treatment. In 

 the succeeding pages we give our observations upon the occurrence 

 of Rhizoctonia upon various plants in America. 



On the Bean, PJiaseoliis vulgaris. 



Early in August, 1900, we received a few complaints of the rav- 

 ages of what appears to be an undescribed stem-rot disease of beans. 

 A field of about twenty acres of red kidney beans near Geneva was 

 considerably injured by the disease. The plants were affected as 

 follows: At a distance of from one to two inches above the surface 

 of the soil there was a place on the stem where the tissues were dead 

 and discolored. Frequently this occurred at the point where the 

 plants commenced to branch. The dead part was dry-rotten clear to 

 the pith, from one-half inch to one inch or more in length, and 

 usually extended entirely around the stem. Being much weakened 

 at the point of a.ttack, it was a common thing for affected plants to 

 be broken over by the wind. When this did not happen the whole 

 plant slowly dried up and died. 



Although larvfe were occasionally found in the diseased stems, it 

 was plain that the trouble was not due to any insect. In all stages 

 of the disease the affected parts were constantly filled with a species 

 of Fusaritirn which, at that time, we suspected to be the principal 

 cause of the disease. However Rhizoctonia liyphse were also pres- 

 ent in a great many cases. Sometimes the medulla of dead plants 

 was completely filled with Rhizoctonia^ and occasionally it was 

 found in early stages of the disease ; but it was not constantly pres- 

 ent in quantity. The crop preceding the beans was corn. 



From. Phel]>s we received bean plants affected with the same dis- 



*SeeBot. Gaz., 27:129. 



f Stone, G. E.. and Smith, R. E.— The Rotting of Greenhouse Lettuce. Mass 

 Exp. Sta., Bui. 69. 



5 



