New York AGRICULTURAL EXPERIMENT STATION. 899 
general treatment which is advocated is stated after the several 
diseases and insects have received individual consideration. 
APPLE DISEASES. 
APPLE TREE CANKER. 
(Sphaeropsis malorum Pk.) 
The term canker, as applied to diseases of trees, is used to des- 
ignate an injury that destroys the bark and lays bare portions of 
wood. It has been discovered that a canker which is doing serious 
damage to apple orchards of this State, is caused by the fungus, 
Sphaeropsis malorum Pk. This is the same fungus that causes 
the black rot of apple, pear and quince fruit. The disease usually 
attacks the larger hmbs where it may be detected by the swollen 
appearance of the limbs, the rough, black bark, and in many in- 
stances bare wood, black and decaying. The area of bare wood 
is, in many instances, not large, but the extent of rough, swollen 
bark may be several feet. The wounds and unhealthy bark inter- 
fere with the circulation of the sap and where a majority of the 
limbs are attacked the tree is greatly enfeebled and may die from 
the effects. 
Some varieties, as the Esopus Spitzenburg and Twenty Ounce, 
are very susceptible to the attacks of this fungus, and many other 
common sorts are by no means exempt. 
Treatment.— No experiments in treating this disease have, as 
yet, been completed; therefore, no definite line of treatment can 
be given. The following suggestions are based on observations 
and studies of the disease as it occurs in a large number of or- 
chards: (1) Remove all diseased limbs wherever practicable. 
(2) When spraying with Bordeaux mixture for apple scab pay 
special attention to coating the limbs with the mixture as well as 
the leaves and fruit. An earlier treatment given when the leaf- 
buds are beginning to open may also be advisable. (3) In some 
instances it will probably pay to scrape or cut the diseased bark 
from the canker spots and scrape the rough bark from other por- 
