14 FARMERS’ BULLETIN 675, 
pupal cell is being formed, the burrow below, which up to that time 
has been kept open, is packed for several inches with wood fiber so 
that the wire can no longer be used successfully. In all cases where 
curves or other obstructions in the burrows interfere with hooking 
the borer out, a little cotton batting dipped in carbon bisulphid should 
be inserted into the hole and the opening plugged with moist earth. 
The gas coming from the carbon bisulphid will penetrate all parts 
of the burrow and will kill the borer. It should be borne in mind 
that the gas is highly inflammable and that fire should be kept away. 
In extensive orchards 
where worming is done on 
a large scale by promiscu- 
ous labor some of the help- 
ers are likely to become 
careless and overlook or 
neglect to destroy an occa- 
sional borer. Every female 
so overlooked stands a 
good chance of maturing 
within a year or two, when 
it will deposit eggs in a. 
half dozen or more near-by 
trees, causing thereby a 
continued and an increased 
infestation in that partie- 
ular part of the orchard. 
The importance of the 
following points should be 
kept in mind by all per- 
sons who practice this 
method of borer control: 
1. Borers should be re- 
Fic. 15,—Adult male and female roundheaded yyoved from the trees as 
apple-tree borer. Male on left, female on ; 
right. Slightly enlarged. (Original.) soon as possible after 
hatching. 
2. Every borer in the orchard should be found and destroyed. 
5. Borers should not be allowed to breed in cultivated or wild host 
trees growing within at least 200 or 300 feet of the orchard. 
It is the practice with many orchardists to put off the fall worming 
of trees until after winter apples are gathered. Observations have 
shown that this practice permits the borers, which feed rapidly while 
young, to remain in the trees too long for safety. Even in so short 
a time small trees may be girdled and killed and larger trees seri- 
ously injured. In the latitude of West Virginia and Maryland the 
