CHAPTER IX 



CHERRY INSECTS 



The insects of the greatest commercial importance to the 

 cherry grower are the plum curculio (p. 243), the cherry fruit 

 flies, the cherry aphis, the pear slug (p. 214) and on the sweet 

 cherries the San Jose scale. Cherry trees are also subject to 

 the attack of the fruit-tree bark-beetle (p. 277). 



The Cherry Fruit-flies 

 Rhagoletis cingulata Loew and R. fausta Osten Sacken 



Most wormy cherries in the United States and Canada are 

 caused by the grub of the plum curculio (p. 243), but through- 

 out the northern 

 United States and 

 Canada there occur 

 two closely related 

 species of fruit-flies 

 whose maggots 

 sometimes infest 

 from one fourth to 

 two thirds of the 

 ripening fruits. Un- 

 fortunately, there 

 is little external 

 T^ ^r. T^ , , •, • r .1 V, e ■* evidence of the 



Fig. 258. — Dorsal and side view of the cherry irmt- 



ny maggot, R. cingulata ix 7 ^J. WOrk of these 



304 



