48 



There arc many other bark-mining" beetles and bark and wood- 

 mining grubs which may aid the primary enemy in killing the trees 

 and in the subsequent destruction of the wood. 



The principal enemy of the spruce-destroying beetle and other 

 bark-infesting enemies of the spruce consists of the woodpeckers, 

 which destroy, it is believed, from 50 to 75 per cent of the broods of 

 the spruce beetle in many hundreds of trees each j^ear. 



Two other enemies of the beetle are of special service in reducing 

 their numbers, a small wasp-like parasitic insect {Bracon simplex) 

 and an ant-like j)redaceous beetle {Thanasimus nuhilus Kl.?). 



The principal methods recommended in this report for preventing 

 losses from the ravages of tlie beetle ma.y be l)riefly summarized as 

 follows : 



I. Regulating the winter cutting so as to include as many of the 

 infested, dying, and dead trees as possible, and i)lacing the logs from 

 the same in the water bef(n-e tlie 1st of June. 



II. Regulating the summer cutting so that as many recently 

 attacked trees as possible may be cut and the bark removed from 

 their trunks and stumps. 



III. Girdling, early in June, a large number of trees, where logging 

 operations will, or can, be carried on tlie following summer and winter, 

 in the vicinity of infested localities, the girdled trees to be felled 

 and the logs containing the broods of the insect attracted to tliem 

 either peeled or placed in the water before the first of the succeeding 

 June. 



The results of one season's experiment in girdling trees indicate 

 that the best time to girdle spruce for this purpose is when the floAV- 

 ers (catkins) are falling from the birch, and while the fire or bird 

 cherry and the hobble bush are in bloom. The girdled trees should 

 be sound and healthy, and not less than 15 inches in diameter. 



The best method of girdling seems to be that of hacking through 

 the bark with an ax into the sap wood and around the trunk i' or o 

 feet above the base. 



Suggestions for utilizing the dead and matured living spruce to 

 prevent loss are as follows : 



A large percentage of the dead spruce appears to remain sound and 

 valuable for pulp wood for a longer jjeriod than has heretofore been 

 recognized. 



The matured living timber should be cut and utilized as rajjidly as 

 possible to prevent insect attack. 



