ORCHARD INSECTS OF THE PACIFIC NORTHWEST 



33 



made by a small, blackish beetle, known as the larger shot-hole borer 

 (Anisandrus pyri Peck). Trees are not attacked unless they are in 



Figure 36. — The spotted cutworm: A, Moth; B, larva extended; C, larva curled up. 



an unheal thy condition, which may have been brought about by 

 mechanical or winter injury, too much water, drought, insects, 

 fungous diseases, or some 

 other cause. Any condition 

 that may result in souring 

 of the sap will attract the 

 borers. The beetles bore into 

 the sapwood and make tun- 

 nels through it in which they 

 lay eggs. The souring sap 

 favors the growth of a fungus, 

 and the young grubs feed on 

 this fungus and not at all on 

 the wood. In the fall the 

 grubs transform to beetles, 

 which remain in the tunnels 

 until spring, when they emerge 

 and construct fresh tunnels. 

 If the tunnels are numerous, 

 the growth of the trees may be 

 affected seriously. 



In order to prevent attacks 

 of this beetle, the trees should 

 be kept in a healthy, vigorous condition; and if they are unhealthy, the 

 cause should be determined and corrected if possible. A wash for 



Figure 37.— Method of constructin;,' cotton tft 



