16 MANUAL OF FRUIT DISEASES 
graphical location, with the age and variety of the fruits con- 
cerned, and with the weather. It is the rule that a fruit shows 
but one or only a few spots (Fig. 5) ; but in cases of severe infec- 
tion as many as 1200 separate lesions have been counted. Where 
only a small number of spots occur these continue to enlarge, 
merging with each 
other until the 
whole fruit is in- ” 
volved. If a great 
number of lesions 
begin simultane- 
ously on the same 
fruit, only a few 
continue to spread, 
the greater number 
remaining as small, 
brown, raised _blis- 
ters on the surface. 
A lesion begins as 
a small light-brown 
discoloration be- 
neath the skin. It 
rapidly enlarges and 
remains firm in tex- 
ture and circular in 
form (Fig. 5). The 
color very soon be- 
comes dark-brown and when about one-eighth of an inch in 
diameter the rotted area is distinctly sunken and sharply defined. 
When about one-half of an inch in diameter small black dots ap- 
pear at more or less irregular intervals beneath the epidermis of 
the sunken area. These may be arranged concentrically or 
scattered without order (Fig. 5). Eventually these little black 
dots, the fruiting pustules of the pathogene, break through the 
Fic. 5. — Bitter-rot of apples. 
