Bean anthracnose 159 



Gloeosporium officinale E. & E. from sassafras, G. gallarum Ch. Rich, 

 from oak gall, and G. psidii Del. from guava. The disease produced, 

 except in the last-named case, resembled sweet-pea anthracnose but 

 did not resemble the bean disease. Shear and Wood (1913:77-89) inocu- 

 lated detached bean pods with anthracnose conidia from avocado, cotton, 

 guava, loquat, mandarin, orange, pitcairnia, and privet, but in the case 

 of none of these did they obtain any infection. Kri'iger (1913) inoculated 

 detached bean pods kept under bell jars with conidia of gloeosporial 

 forms from apple, banana, and tomato, and, while good infection was 

 obtained on checks consisting of detached fruits of the respective hosts, 

 the result on bean pods was doubtful; no infection was obtained on the 

 uninjured pods, although there was some mycelial growth in the tissue 

 surrounding the injury made on other pods. Gardner (1918 : 23) inoculated 

 five varieties of beans with Colletotrichum lagenarium, with negative 

 results. 



On inoculating bean seedlings of several varieties with spores of the 

 anthracnose fungus from sweet pea and from mandrake, the writer did 

 not obtain any infection. Fair infection was obtained on sweet-pea 

 seedlings inoculated with spores of the form from sweet pea, and on the 

 leaves and stems of young mandrake plants growing in the woods and 

 of those transplanted to the greenhouse inoculated with the form from 

 mandrake. From his own results and from those obtained by others, 

 the writer is inclined to believe that, in general, each of the various 

 anthracnose fungi is confined to its own host or to closely related plants. 



ECOLOGIC ASPECTS 



In the preceding discussion frequent reference has been made to 

 weather conditions favorable to infection. There is no question that 

 the weather is an important factor in the growth of this fungus, just as 

 it is in the growth of higher plants. The fungus has its ups and downs 

 according as the season is wet or dry. Temperature and humidity are the 

 two factors of greatest importance, and of these the latter is usually the 

 controlling one in the Northern States. This has been generally recognized 

 by growers, and its significance in the development of the disease has been 

 pointed out in some of the earlier accounts. 



Edgerton (1910:28, and 1915:248) has shown that temperature is the 

 controlling factor under conditions in Louisiana. The disease, while 



