U.S. D. A., B.E. Bui. .58, Part II. F.I. I., August 18, 1906. 



SOME INSECTS INJURIOUS TO FORESTS. 



THE WESTERN PINE-DESTROYING BARKBEETLE. 



(Dendroctoiiiis- birricontin Ix'c.)« 



By J. L. Wkbb, 

 Special Field Aoent, Forest Insect Investigations. 



INTRODUCTION. 



The o})j(^ct of this pa})er is to o;ive availa])le information on this 

 insect and methods of combating it, with s{)ecial reference to the 

 results of investigations by the writer during the summer of 1905 in 

 central Idaho. 



The need of the investigations was suggested in a letter dated 

 August 10, 1904, fi-om Mr. GifTord Pinchot, forester of the U. S. 

 De])artment of Agi'iculture, to Dr. T.. O. Howard, chief of the Bureau 

 of Kntoinology, as follows: 



I learn from the Payette Lumber and Manufncturino: Company, one of the Weyerhaeusers, 

 whose hind lies on the Payette River north of Boise, tliat the pine in their holdings is said to 

 he dying from the attacks of insects. If it were possible for you to assign Doctor Hopkins, 

 or one of his assistants, to make examination of this region, unless it has already been done, 

 I should greatly appreciate it, and I shouUl likewise appreciate your sending to Mr. Edgar M. 

 Hoover, general nuinager of that company at Boise, any information you may have bearing 

 on thi.s subject. 



In respon.se to this re([nest the matter was referred by Doctor 

 Ilowiird to Dr. A. D. Hopkins, in charge of forest insect investigations, 

 for attention, and Mr. II. E. Burke, an assistant, was instructed to 

 make preliminary investigations in October of the same year. In May, 

 1905, the writer was assigned to this work, with instructions from Doc- 

 tor IIoj)kins to make a detailed study of the forest insects of the region, 

 with s|)ecial reference to determining the following points: (1) The 

 relation of the several >-j)eci(\s of in.sects to the dying of the trees; (2) 

 the number of species involved, the relation of each to j^rimary and 

 secondary attack, and the life histories of the jirimarv and secondarv 

 enemies; (,3) the extent of the infested ar(>a, the percentage of timber 

 killed each year during the past two or three years within given areas, 

 th(> aj^proximate lo.sses. <>tc.; (4) the relation of logging ojierations to 



a Order»Coleoptera, family Scolytidce. 



17 



