156 ORCHARD INSECTS 



liable to attack, but especially the lower part of the trunk. 

 The larvffi burrow in the wood, principally in the sap wood, 

 and in bad cases they may completely girdle the tree. 



Clean Culture. — Trees standing in sod, or with weeds about 

 the trunks, are especially liable to attack, much more so than in 

 well cultivated orchards. Take the case of a single young orchard 

 which was examined on account of some of the trees being badly 

 attacked by borers. The land was under cultivation, but several 

 patches were very weedy. Other parts were entirely free from 

 weeds; and without exception the trees attacked by borers were 

 those standing in weeds. This suggests one of the best methods 

 of fighting this pest in sections where it has been found trouble- 

 some — thorough cultivation. 



Careful Examination. — The presence of the borers may be 

 detected usually by the castings or dust which is thrown out by 

 the larva as it bores through the wood. In badly affected trees 

 it is also shown by the sickly appearance of the tree, but no one 

 should ever wait for this sign. In sections where this pest is 

 likely to be troublesome the trees should be examined carefully 

 at least once a year, the best time being early autumn. 



Dig Out Borers. — ^When a tree is found to be affected the 

 only thing to do is to cut out the borer. A good sharp knife and a 

 stout wire are the usual equipment. Cut into the burrow and 

 follow it up until the borer is found. Sometimes the wire is 

 used to push into the hole and kill the borer without getting it 

 out of the burrow. This is all right provided one is certain that 

 the borer is killed, and of course it saves some cutting of the tree. 



Prevention. — It seems unfortunate that some really satisfac- 

 tory method of prevention has not been devised. Various 

 schemes have been suggested and some of them are certainly 

 w^ortli trying. A piece of wire screen, if put on carefully so 

 that the female insect can neither crawl down behind it, nor 

 deposit the egg through it where the screen rests against the 

 bark, will prevent any attack on the trunk, where most of the 

 trouble occurs. Another plan worth trying, in sections where 

 these insects are known to be plentiful, is to wash the trunks 



