CHAPTER VII 



INSECTS INJURIOUS TO THE APPLE 



THE apple is so universally grown and is such a valuable addi- 

 tion to our food supply that conditions surrounding its growth have 

 been perhaps more carefully studied than those of any other tree, 

 and the various insect pests attacking it have been the subject of 

 careful investigation on the part of entomologists. The results 

 of some of this work are given in this chapter. 



INSECTS ATTACKING THE TRUNK AND BRANCHES 



The Flat-headed Apple Tree Borer. The adult is a broadly- 

 flattened, metallic bronze-colored beetle (Chrysobothris femorata 

 Fab.). It is about two-thirds of an inch in length, with short 

 antennae, conspicuous eyes, and a more or less ornamented back. 



The males are smaller than the 

 females (Fig. 91). It is fre- 

 quently seen during the spring 

 and summer months, first ap- 

 pearing in May or June upon 

 the trunks of the trees. 



Life History and Habits. 

 The female oviposits in cracks 

 or under the bark. Diseased 

 or dying trees are preferred. 

 It attacks both fruit and forest 

 trees, notably young trees. 

 Sometimes maple trees may 

 be infested. The eggs are yellow and usually several are grouped 

 together. The larva is large, legless, and with a broad, flat 

 head. It works into the wood, digging irregular flat channels, 

 sometimes completely girdling a tree. Its presence is often indi- 

 cated by sawdust-like excrement on the bark. The winter is 

 spent in the larval stage, possibly occasionally as pupa. Ordinarily 

 it pupates in the spring, just under the bark the pupal stage 

 being very short, approximately three weeks. When the adult 

 beetle emerges from the trunk, it leaves an elliptical hole in the 

 bark, while the hole left by the following borer is round. 

 68 



FIG. 91. Flat-headed apple-tree borer. 

 (U. S. Bu. Ent.) 



