Bean Anthracnose 141 



variety as the healthy seed used. Davis White Wax was used in all 

 experiments except Experiment IV, in which Refugee Wax was used. 

 The old vines and pods affected by anthracnose were of several varieties 

 and no attempt was made to keep them separate. Most of them were 

 well covered with anthracnose lesions. Care was taken to remove all 

 seeds, even shriveled ones, from the pods. The vines and the pods left 

 in the garden over winter were much overrun with numerous saprophytic 

 fungi and were somewhat decomposed by spring. Those kept in the seed 

 house were as intact as they were when placed there. 



In setting up an experiment, for example flat 6, the soil was first placed 

 in the flat, the seed was then disinfected and planted usually in four or 

 five rows to a flat, the vines and pods were placed over the surface to a 

 depth of about one and one-half or two inches, the flat was placed in the 

 greenhouse, and tap water was sprinkled on it until the soil was saturated. 

 Unused sphagnum was placed over the flats unmulched by pods or vines 

 in the case of Experiments V and VI. Each flat was prepared separately 

 and every precaution was taken to avoid contaminating one with another. 



The temperatures at which the flats were kept in the different experiments 

 varied considerably, but when possible they were kept between 65° and 

 70° F. This was done in order to favor the fungus and permit infection 

 to take place, and for this reason also the flats were watered more profusely 

 than is best for good germination of bean seed. As a result the germination 

 was very poor in some instances. 



Records giving the extent of affection are not included here as they 

 are all very much alike. On nearly every plant the stem was affected 

 with one or more lesions, and often these occurred only at the surface 

 of the ground. A few plants had lesions on the leaves. Lesions on coty- 

 ledons coming from the spotted seed used in flat 2 were not considered. 

 The records were usually taken in about three weeks or less after the 

 experiment was set up, in order to get them before secondary infection 

 occurred. There is no doubt that secondary infection did occasionally 

 occur. 



These experiments, the results of which are shown in table G, cannot 

 be regarded as ideal. The results obtained in some cases — for example, 

 from flat 1 in Experiment II — may seem to cast doubt on their reliability. 

 But when the entire series is considered, there can be no doubt that the 

 results show the possibility that old bean pods and vines serve as a source 



