244 



APPLIED ENTOMOLOGY 



and particles of bark, and lined with silk. These cocoons may be at the 

 openings of the burrows but are more frequently fastened to the bark 

 just about at the level of the ground. After 3 to 4 weeks in the pupa 

 stage, the transformation to the adult is completed and the pupa breaks 



its way through the cocoon until it is 

 about halfway out. Then the pupa skin 

 splits and liberates the moth. 



The injury caused by this insect when 

 it is abundant is often serious. The feeding 

 of the borers is in the cambium layer which 

 is tunneled through in an irregular way, 

 interfering with the growth of the trees, 

 and where these are small they are often 

 girdled. The weakened trees also become 

 more liable to injury and destruction by 

 bark borers and other insects. 



Where the tunnels are formed, a flow of 

 sap results in the pouring out of gum and 

 this substance on the bark near the ground 

 is usually a good indication of the presence 

 of the borers. 



Control. Of the many methods which 

 have been tried, only two appear to have 

 given at all valuable results. These 

 are " worming" and " mounding." Worm- 

 ing is the removal of the borers late in the 

 fall and again in the spring, the date for 

 the spring treatment varying with the 

 locality but before the borers have com- 

 pleted their feeding. A day or two before 

 this treatment the earth around the trunk 

 should be removed to a depth of several 

 inches, so that fresh gum and sawdust pro- 

 duced thereafter by the borers, or below 

 the level of the ground, will show. With 

 these as guides where to work, the borers 

 can be located and removed with a sharp 

 knife, and a light, pointed wire, care being 

 taken to cut as little as possible and to 



leave clean-cut edges. Then replace the earth. In the spring, following 

 the " worming," mound up the earth six or eight inches high around 

 the trunk and leave it there until after the moths are done flying, but 

 remove it in time for the bark to harden before winter. This mounding 

 forces the moth to lay its eggs further up where the bark is tough 



FIG. 240. Larva of Peach Borer 

 Moth and its work on a young 



peach tree. (From U, S. D. A. 



Farm. Butt. 908.) 



