'New Yoek Ageicultueax, Expekiment Station". 399 



general treatment whicli is advocated is stated after the several 

 diseases and insects have received individual consideration. 



APPLE DISEASES. 



APPLE TEEE CANKEE. 



{Sphaeropsis tnalorum 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 limbs 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- 



