INSECT ENEMIES OF WESTERN FORESTS 109 



Either peeling the bark from infested trees before new adults 

 form, or burning it, will kill the Jeffrey pine beetle. Methods used 

 for the control of the western pine beetle are usually employed for 

 this species also. 



The lodgepole pine beetle {Dendroctonus murrayanae Hopk.) 

 develops in large numbers in freshly cut stumps and attacks the 

 base of old, weakened lodgepole pine in eastern Washington, Idaho, 

 Montana, Wyoming, and Colorado. Ordinarily it is not an aggres- 

 sive enemy, but it occasionally does kill overmature lodgepole pine 

 left standing follow^ing tie operations, timber sales, or other cuttings. 

 Fortunately such outbreaks die down at the close of the operation. 

 In some instances trees are killed during the first year by the basal 

 attacks of the lodgepole pine beetle, or it may require 3 or 4 suc- 

 cessive years of attack before the resistance of the trees is sufficiently 

 lowered to render them attractive to other bark beetles. In other 

 cases they are abandoned by the insects before the attacks prove 

 fatal. In any case, this basal damage to the tree may be considered 

 as primary, as it is the first weakening influence. 



The adults, which are about one-fourth of an inch in length, have 

 reddish wing covers, wdiile the prothorax and head are a dark 

 brown or black. Their attacks, which are made on stumps or on 

 the boles of the trees, usually within 4 or 5 feet of the ground, are 

 easily recognized by the large pitch tubes, an inch or more in diam- 

 eter, which form at the entrance holes. On reaching the cambium 

 the attacking beetles construct short ^gg galleries, ranging from 5 to 

 12 inches or more in length, directly between the bark and w^ood. 

 Eggs are deposited along the sides of these galleries and are sepa- 

 rated from one another by boring dust. The larvae feed away from 

 the ^gg gallery, keeping together in a common excavation or brood 

 chamber. There are no separate or individual larval mines. Trans- 

 formation to pupae and new adults takes place in cells constructed 

 in the uneaten part of the inner bark or in cocoonlike structures com- 

 posed of excrement in the brood chamber. The seasonal history has 

 not been thoroughly worked out, but there appears to be one genera- 

 tion a year. Outbreaks of this insect are seldom of sufficient economic 

 importance to warrant control measures. 



The red turpentine beetle {Dendroctonus valens Lee.) {36) attacks 

 the base of either injured, dying, or healthy trees, or freshly cut logs 

 and stumps of all pines and occasionally spruce, larch, and fir 

 throughout the western and northeastern part of the United States 

 and southern Canada. Ordinarily it is not considered an aggressive 

 tree killer but it does do considerable primary damage and so weak- 

 ens trees as to make them more susceptible to attack by other bark 

 beetles. In some cases, such as with Monterey pine in California, it 

 causes sufficient damage to result in the death of the tree. It is par- 

 ticularly active around logging operations, where it not only works 

 in the stumps, but will often produce catf aces on the bases of trees 

 left in the reserve stand. 



The adults are the largest bark beetles of this genus, measuring 

 from one-fourth to three-eighths of an inch in length, and are dis- 

 tinctly reddish in color. They are often called barber beetles by 

 woodsmen, on account of their ability to clip hairs, and are com- 

 monly, though erroneously, thought to be the bark beetles responsible 



