INSECT ENEMIES OF WESTERN FORESTS 



57 



Figure 22. — Sitka spruce along" the Washington coast killed by the spruce 

 aphid (Neomyzaphis abietina) . 



to brownish-black species, which lives on the needles of ponderosa 

 pine in Colorado. Many kinds of aphids infest the leaves of various 

 broad-leaved forest trees, but these are of little importance to 

 forestry. 



Large, long-legged, dark-colored aphids with naked bodies or 

 lightly covered with a powdery wax belong to the genus Cinara. 

 They are frequently found feeding on the terminal twigs of 

 coniferous trees, where they insert their beaks through the tender 

 bark. The copious flow of honeydew causes a dense smutting of 

 the trees, sometimes making them appear as if they had been 

 sprayed with creosote. At times the work of these aphids causes 

 considerable injury. More than 35 species are recorded from the 

 Western States. 



Dirty-white, waxy encrustations on the bark of trunk, limbs, 

 and twigs; white, cottony tufts on needles and twigs; and cone- 



