SECTION OF VEGETABLE PATHOLOGY. 325 
the pustules which stud the surface are less numerous and less con- 
vex. Inadvanced stages the berries lose their hold upon the pedi- 
cels and fall to the ground at the slightest jar. Those destroyed by 
black-rot usually remain strongly adherent and generally fall with 
their pedicels attached. 
Fic. 1. Illustrates a highly magnified vertical section through one of the 
fruiting pustules of the fungus of Bitter-rot. A compact growth of 
spore-bearing hyphze has burst through the epidermis, c,c. Below 
' is the browned and dead tissue of the berry, d,d, growing through Fie.2. Spores of Bitter- 
which are the mycelial threads of the fungus... ’ rot, B, and White-rot, 
W. 
The mycelium of the fungus of bitter-rot penetrates the tissues of 
the berries, even entering the seeds, for upon the latter it is not un- 
common to find the fruit of the parasite. 
The spores produced are very minute, ovoid or navicular-form, and 
have rather thick walls. They germinate quickly when sown in 
aerated juice of grapes diluted with water. 
Bitter-rot is most to be feared when frequent rains occur during 
the ripening period, but, like other fungus diseases of this class, it is 
sure to be most severe in poorly drained soils and on vines previously 
weakened by mildew. 
B.—W hite-rot. 
This disease appears to be of American origin, although the fungus 
causing it was first recognized in Italy, in 1878. In 1886 it was dis- 
covered in France, and during the past season (1887) has become 
widely spread in the latter country, occasioning no little alarm. 
Frequent accounts of it have been published in #rench and Italian 
journals, the most complete and best illustrated being that given by 
Dr. F. Cavara.* 
Since its discovery in this country, in September of the present 
year, it has been described by the writer in Colman’s Rural World, 
October 27, 1887; and in the proceedings of the New Jersey Horti- 
culturat Society for 1887, p. 139. 
* Intorno al Disseccamento dei Grappoli della Vite. Instituto Botanico della R. 
Universita di Pavia, 1888, p. 11, Pl. IV*. 
