INSECT ENEMIES OF WESTERN FORESTS 



19 



the dead cone, where the beetles usually remain over the winter. 

 The damage to the cone crops of ponderosa, western white, and 

 sugar pines is often very severe. In some years from 25 to 75 per- 

 cent of the sugar pine cones have been killed over large areas. In 

 other pines the damage is less conspicuous. Spraying cone-bearing 

 trees with DDT early in the spring to prevent attack might prove 

 effective. 



A number of species found in western pines have been described 

 by Hopkins — and named for their principal host trees. The follow- 

 ing list gives the species of Conophthorus that may be found in 

 western forests : 



Species of Conophthorus Hosts and distribution 



apachecae Hopk Apache pine. Arizona. 



contortae Hopk Shore pine. Oregon coast. 



edulis Hopk Pinyon pine. Colorado, Arizona, and New Mexico. 



flexilis Hopk. . Limber pine. Colorado and Montana. 



lambertianae Hopk. (fig. 5) . Sugar pine and western white pine. Oregon and 



California. 



monophyllae Hopk Singleleaf pine. Southern California. 



monticolae Hopk Western white pine. Idaho, Washington, and 



Canada. 

 ponderosae Hopk Ponderosa pine and Jeffrey pine. Pacific Coast 



States. 



radiatae Hopk Monterey pine. California. 



scopulorum Hopk Ponderosa pine. Rocky Mountain region. 



II 



Figure 5. — The sugar pine cone beetle (Conophthorus lambertianae) : A, 

 Adults, slightly enlarged; B, pitch tubes on stems of blighted sugar pine 

 cones, indicating cone beetle attack. 



