348 MANUAL OF FRUIT DISEASES 
been the subject of horticultural writings and discussions for 
many years. Very recently it was found on pears in Australia. 
As already indicated, the disease is found more commonly 
in nurseries than in orchards, yet the latter are not exempt 
from attacks of the leaf-blight pathogene. In the nursery 
the trouble affects the leaves and twigs of seedlings; in the 
orchard, the fruits (Fig. 98), in addition, are susceptible. It 
appears that all varieties show 
the disease, yet the Kieffer and 
Angouléme are more resistant 
than the Seckel, Wilder Early and 
Sheldon. It has also been ob- 
served that the Flemish, Lawrence, 
Bosc and Clapp Favorite are 
resistant. 
Symptoms. 
The disease makes its appear- 
ance early in the spring soon 
after the leaves develop. There 
develops a small circular, carmine- 
red spot, first on the upper, and 
then penetrating to the lower, sur- 
face. The color soon changes from 
nee ee ae em red to dark-brown, with a slightly 
tar peep Ene, elevated, minute black spot in the 
center. If the lesions are numer- 
ous, they may merge, and thus the tissue between them turns 
brown. Affected young leaves shrivel; older ones change 
only in color. Badly diseased leaves turn yellow and fall 
prematurely. 
The fruit shows the same carmine-red spot which afterward 
assumes a darker color (Fig. 98). The skin is roughened, and 
the growth of the epidermis is hindered, causing a deep crack 
in the flesh. 
