In the following list of h^st trees ">f each species 

 :f killing insects only our commercial tree species are con- 

 .-ilercd . Each species of insect may attack other species of 

 pines, firs, etc., but if the Forost officer is familiar with 

 the common species attacking the well-knrn-;n trees he will often 

 I'S able to locate the cause of infestation of isolated cr Ircal 

 ^pecies. The species of trees attacked are given in the order 

 ">f their importance in relation t^ the depredations of each 







p--cies of beetle: 



HOST TREES, IN "SOTS. 



lambertiana (Sugar pine) Dendroctonus* monticolae 



cont'Tta (Lodgep^le pine) (ITountain Pine Beetle) 



g^ndor.-aa (Yellow pine) 



mcnticola (Western white pine) 



ponderosa (Yellow pine) Dendroctonus* brevicomis 



(Western Pine Beetle) 



jefireyi (Jeffrey pine) Dendroctonus* jeffreyi 

 ponderosa (Yellow pine) (Jeffrey Pine Beetle) 



ponderosa (Yellov/ pine) Dendroctcnrs* valens 



lambertiana (Sugar pine) (Red Turpentine Beetle) 



contorta (Lodgepole pine) 



jeffreyi (Jeffrey pine) 



nnntic^la (Western v/hite pine) 



IT 



TT 



IT 



IT 

 H 



ir 

 II 

 IT 

 IT 



>oudotsuga ta:ci~ (Douglas fir) Dendroctonus pseudotsugae 



(Douglas Pir Beetle) 



IT 



: inus lambertiana (Sugar pine) Melannphila gentilis 

 ponderosa (Yellow pine) (Pine Plathead Bcrer) 

 jeffreyi (Jeffrey pine) 



See "The Genus Dendroctonus", by Dr. A. D. Hopkins, Technical 

 Series, W. 17, Pt . 1, U. S. Department of Agriculture. 



-15- 



