448 
Hampshire. It is dark brown or black 
in color and the affected tissue com- 
paratively firm. It is thus readily dis- 
tinguished from the soft rots. It may 
start on any part of the fruit, but often 
begins at the blossom and frequently 
follows insect stings. The disease is 
primarily a rot of ripe fruit, but it may 
often be found as dark brown spots one- 
eighth to one-half inch in diameter sev- 
eral weeks before the apples are mature. 
These spots may develop very slowly 
until about picking time, but after that 
spread rapidly, involving the whole 
apple. As the rot develops, numerous 
minute, black elevations may be seen on 
the apple (Fig. 1). These are_ spore 
producing bodies of the fungus and are 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
known as pycnidia. The rot does con- 
siderable damage in cellar storage, but 
is especially common on the fruit left 
on the trees or ground. This worthless 
fruit becomes a source of infection the 
following spring. 
Canker is a term applied to rough, 
unsightly wounds that are known to be 
due to the action of fungi. The most 
common variety of this trouble is the 
“black rot canker,’ also known as the 
“New York apple tree canker.’* Both 
large and small limbs are attacked and 
* Paddock, Wendell. The New York Apple 
Tree Canker. New York Agricultural Experi- 
ment Station Bulletin 163. 
Paddock, Wendell, Ibid (Second Report), New 
tbe Fr aida Experiment Station Bul- 
etin 5. 
Fig. 1. 
Black Rot Canker on Limb, Early Stage of Leaf Spot (upper figure) and Late Stage 
of Leaf Spot (lower figure). 
Black Rot of Apple Due to Sphaeropsis malorum, Showing Black Rot on Fruit, 
—New Hampshire Experiment Station. 
