rve 



Circular No. 864 



April 1951 • Washington, D. C. 



UNITED STATES DEPARTMENT OF AGRICULTURE 



3 



THE WESTERN PINE BEETLE 



A Serious Enemy of Ponderosa Pine 



%) 



By 



John M. Whiteside, entomologist, Division of Forest Insect Investigations, 

 Bureau of Entomology and Plant Quarantine, Agricultural Research Adminis- 

 tration 1 



CONTENTS 



Importance 



The beetle 



Work and habits 



How to recognize an attack. 

 Method of attack, _ 

 Seasonal history. 



Page 

 1 

 2 

 3 

 3 

 5 

 6 



Control 



Natural control. 

 Direct controL_ 

 Indirect control. 



Page 

 7 

 7 

 8 

 9 



Types of infestation 7 



IMPORTANCE 



The western pine beetle ^Dendroctonus brevicomisluec.) is the most 

 destructive insect enemy of ponderosa pine (Pinus ponderosa Lawson) 

 in the virgin pine forests of California, Oregon, Washington, Idaho, 

 western Montana, and British Columbia. In the United States during 

 the period 1921-15 this beetle, no larger than a grain of rice, killed 

 approximately 2 million trees, or 1 billion board feet of timber, every 

 year. This destruction represents a gross loss of nearly 25 billion 

 board feet of timber, worth 100 million dollars on the stump — more 

 softwood lumber than was produced in the entire United States in 

 1942, when the lumber industry was "all out" for World War II. In 

 many sections of our forest ponderosa pine stands are no longer con- 



1 The writer is indebted to the many entomologists of the western forest-insect 

 laboratories of the Division, from whose published and unpublished reports this 

 circular has been compiled. J. M. Miller and F. P. Keen supplied most of the 

 material. 



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-51 



