THE CHERRIES 159 



planted and all varieties should be so pruned as to make 

 low spreading heads, an easy process with the Sour type 

 but more difficult with the Sweet. The possibilities of 

 profit from commercial planting depend very largely 

 upon the accessibiHty of a good market. 



Enemies 



Cherry trees are particularly liable to destruction by 

 Black Knot, caused by the same parasitic fungus that 

 attacks the plum. This is the main reason for the 

 disappearance of the cherry trees on thousands of home 

 grounds. A constant watch for the first signs of the 

 disease — shown by the swelling of the bark — -should be 

 kept and such injured parts immediately be cut off and 

 burned. All wild cherry or wild plum trees that show 

 the Knots in the neighborhood should also be burned 

 and united action be taken by the whole community to 

 suppress the disease. 



The cherry is subject to much the same injury by 

 Leaf-spot and Brown Rot that the plum is. The Leaf- 

 spot is often injurious to young trees and in moist cli- 

 mates is frequently supplemented by the Cherry Powdery 

 Mildew, which causes the leaves to curl up and drop off. 

 The Brown Rot is usually less destructive than on plums 

 because the cherry fruits do not touch one another as the 

 plums often do. Spraying with the lime-sulphur wash 

 is helpful in preventing all of these diseases. 



The Plum Curculio also attacks cherries and some- 

 times causes the loss of much of the crop. In large 

 plantations the injury may be prevented to a great 

 extent by spraying with arsenate of lead, but where the 

 attack is severe upon a few trees the jarring method 



