INSECT PESTS 



225 



last, of a steel gray color, and moves about in the day- 

 time. It lays its eggs not only on the trunk, but some- 

 times on the main branches as well. It is generally 

 found on the south side, and begins its work where 

 there has been some injury to the bark. The larvae of 

 the flat-headed borer work only in the bark and sap- 

 wood, and are more easily destroyed than the round- 

 headed borer. The insect generally completes its 

 changes in one year, and in many places it is more 

 abundant than the round-headed borer, and is more 

 destructive. Figure 116, d, shows 

 the perfect beetle ; b, the chrysalis ; 

 a, the larva, with the head en- 

 larged at c. 



Remedy The presence of this 

 larva may be known in the same 

 way as that of the round-headed 

 borer, and the remedy is the 

 same. The use of washes on the 

 trunk or branches is of uncertain, 

 if of any, value, while examina- 

 tion, if thoroughly made, is sure 

 to reveal the insects if present, 

 and there is no uncertainty about it, while the cost 

 is less. 



The Oyster Shell Bark Louse (Mytilaspis pomorum) 

 This insect, shown in large numbers in Figure 

 117, injures the apple tree by sucking the juices from 

 the twigs and branches. While young the minute insects 

 move about freely, but soon, finding a desirable place, 

 fix themselves and feed there until they die. During 

 the winter and spring we only find the dead shell and 

 numerous eggs securely covered by it. In this state the 

 shell or covering is so securely sealed that it is with 

 difficulty removed from the bark, and can be destroyed 

 only by very strong insecticides. Figure 117, a, shows 



Fig. 116-Flat-Headed 

 Apple Tree Borer 



