104 Report of the Botanist op the 



treatment. In the succeeding pages we give out observations 

 upon the occurrence of Rhizo'Ctonia upon various plants in 

 America, 



ON THE BEIAN. 



(Phaseolus vulgaris.) 



Early In August, 1900, we received a few complaints of the 

 ravages 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 

 stom 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 en- 

 tirely around the stem. Being much weakened at the point of 

 attack, 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 larvae 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 Fusarium, which at that time we suspected to 

 be the principal cause of the disease. However, Rhizoctonia 

 hyphse were also present in a great many cases. Sometimes the 

 medulla of dead plants were completely filled with Rhizoctonia, 

 and occasionally it was found in early stages of the disease; hut 

 it was not constantly present in quantity. The crop preceding 

 the beans was com. 



From Phelps we received bean plants affected with the same 

 disease and some of them showed an abundance of Rhizoctonia. 

 Mr. F. M. Rolfs^ also reports having found Rhizoctonia on beans 

 on Long Island. 



^Our thanks are due Mr. Rolfs who has made a great many field obser- 

 vations for us. 



