92 BIGGIE ORCHARD BOOK 



down permanently. This, of course, depends some- 

 what on climate, variety, and soil. In regard to 

 sun -scald injury and preventive measures, consult 

 Chapter IX ; for gum, see Chapter XII. 



VARIETIES WHICH ARE OFTEN SELF-STERILE. 

 S. W. Fletcher places three varieties in this list : 

 Napoleon, Belle de Choisy, and Reine Hortense. 



PRUNING. The less cherry trees are pruned the 

 better. Of course, it is necessary to cut back a tree at 

 time of planting, and to guide it in the right path for 

 the first two or three years. The fruit of the cherry 

 is produced only on wood which is two or three 

 years old. 



PRINCIPAL INSECT PESTS. Aphis (lice) : Attack 

 the leaves on ends of tender young shoots. Remedy : 

 Tobacco solution, applied early, before leaves curl. 



Borers : The flat-headed cherry-tree borer is very 

 much like the flat-headed apple-tree borer. 



Curculio : The plum curculio often stings cher- 

 ries, too, but the injured cherries are not so apt to 

 drop off. 



Cherry fruit-fly or maggot : A fly which punctures 

 the skin of the fruit, and deposits an egg which soon 

 hatches into a small worm or maggot. The curculio 

 makes a crescent-shaped puncture ; this fly does not 

 Prof. Slingerland says : " Place a temporary wire net- 

 ting around the trees and turn hens therein soon after 

 the fruit is picked. ' ' 



Leaf rollers: These pests feed on the leaves 

 and roll them together for protection. Remedies : 

 Arsenical sprays ; cut off and burn badly infested 

 twigs. 



