144 Murtier F. Barrus 



bean tissue where it would be in continued contact with the seedlings. 

 In ordinary practice this would occur only accidentalby if at all. But 

 when considerable wet weather follows planting, infection may be expected 

 to occur- from contact with old affected vines spread with manure on the 

 surface of the soil after plowing, or from such affected vines as come to 

 the surface after having been plowed under. 



Muncie (1917:15-21) carried on tests to determine whether the bean- 

 anthracnose and bean-blight organisms are able to winter over in old 

 bean trash containing affected vines or as spores in the soil. He observed 

 during the summer a small amount of anthracnose on the plants grown 

 in pots where spores had overwintered and where old anthracnose-spotted 

 vines of the second as well as the next preceding year had overwintered. 

 A greater number of plants became affected with blight in these trials. 

 From these data Muncie is convinced that the causal organism of both 

 anthracnose and blight can live over winter in the soil in diseased bean 

 trash and as spores or bacteria in the soil, and infect the crop of the 

 following season. His field observations of preceding years doubtless 

 strengthen this opinion. 



Schaffnit 1920) obtained spores with unimpaired germination up to 

 lary 12. 1920. from pods of the harvest of the preceding year. Meyer 

 (1910) finds the first appearance of the disease always on plants growing 

 on damp ground directly where fresh stable manure has been applied 

 but not where commercial fertilizers have been used. Pfeiffer (1910), 

 however, believes the organism does not come from manure, as he has 

 observed the disease commonly on land that never receives it. Muncie 

 (1917:21) records inoculations made with an inoculum consisting of 

 dung from a cow fed with bean straw infected by C. lindemuthianum 

 and Bacterium phaseoli, but states that he was unable in this way to produce 

 anthracnose and that blight appeared on only one plant. It is not unlikely 

 that beans planted on heavily manured ground would produce so rank 

 a growth that moisture conditions about them would be more favorable 

 for infection than with plants not so vigorous. It is also possible for the 

 pathogene to be introduced into a field with manure having infected bean 

 straw mixed with it. 



Further infection of the plant and spread of the disease through the field 



The inoculation of the leaves, the petioles, the branches, and the 

 inflorescence of the older plants occurs in the same manner as that of 



