292 



SCHOOL ENTOMOLOGY 



weeks, when they form cells at the end of their burrows and 

 transform to pupae, from which the adult beetles emerge 

 and eat their way out through the bark about a week later. 

 The destruction of all dead and diseased wood and the 

 burning of prunings is the most 

 important factor in the control 

 of this pest. Affected trees should 

 be liberally fertilized so that 

 they may better withstand in- 

 jury. The best means of pre- 

 venting the beetles from laying 

 their eggs seems to be to white- 

 wash the trees in early spring, 

 again in mid-summer, and again 

 in October. Use a good thick 

 whitewash and add one-fourth 

 pound of common salt or Portland 

 cement to each pailful to make 

 it more adhesive. 



155. Apple-tree Borers. 

 Young apple and quince or- 

 chards are often seriously injured 

 by the Round-headed Apple-tree 

 borers * which burrow into the 

 heart wood and often girdle the 

 trees. Their presence may be 

 detected by the retarded growth 

 of the trees, a yellowing of the 



foliage, the sawdust castings at the entrance of the bur- 

 rows, and the discolored bark over the burrows, from 

 which sap sometimes exudes. Injury is most severe in 



FIG. 210. Work of the fruit- 

 tree bark-beetle, showing 

 the main galleries, the side 

 or larval galleries, and the 

 pupal cells. (After Ratze- 

 burg.) 



* Saperda Candida Fab. 

 No. 40a, Appendix A. 



Family Cerambycidce, see page 120 and 



