No. 6. DEPARTMENT OF AGRICULTURE. 401 



the surface that tlie bark over these cavities cracks and some of the 

 "sawdust" falls out. During the winter the borers are quiet, but 

 resume their work the following spring. During this second year 

 the}' work deeper into the tree, boring in the heart wood, but at the 

 approach of winter become quiet again. The next spring they bore 

 out to the bark and then become quiet pupae for a short time, after 

 which the adult beetle formed from the pupa during this stage 

 gnaws through the thin layer of bark left over the hole and escaj)es. 



Food Plants. 



This borer works in the trunks of the apple, pear, quince, thorn, 

 English hawthorn. Mountain ash, June berry and other trees. 



Treatment. 



To prevent this insect from laying its eggs on the tree, a wrapping 

 of several thickness of paper may be placed closely around the trunk. 

 The paper should be covered by a little earth at the bottom and 

 reach up about two feet, and be closely tied, so that the beetles can- 

 not get between it and the trunk. The wrapping should be applied 

 about May 10th and remain at least until September. 



Wire window-screen netting can also be used for this purpose, care 

 being taken that the lower edge of the netting be covered by the 

 earth, and that some little space is left between it and the trunk ex- 

 cept where it is fastened tightly around the tree about two feet 

 above the ground. A protector of this kind will last for several years 

 and if properly applied in the first place, will need no attention. 



Either of these methods will protect the lower part of the trunk; 

 but as the beetle sometimes lays its eggs higher up, it is advisable 

 to whitewash the trunk from the lowest fork down to the top of the 

 protector at the time when this is put in place. 



When borers are already in the trunk, their presence may often be 

 discovered by the accumulation of sawdust around the base. In 

 such cases the insects may be cut out with a knife, or if they are too 

 far in to be conveniently reached in this way, a sharp-pointed flexible 

 wire may be used with which to follow the hole and pierce the borer. 

 Frequently when the burrow can be found, the most convenient 

 treatment is to pour a little carbon bisulfide on some cotton, place 

 the cotton in the hole and then plug up the hole outside, leaving the 

 fumes of the gas to kill the borer. 



26—6—1902 



