August, '19] HERBERT: WESTERN SHADE TREE PESTS 333 



to Barstow. The last specimens were seen at Inyokern, near the 

 southern end of the Owens Valley in California. 



In all of this area the present center of abundance is in the region 

 bordering the Colorado River in the vicinity of Blythe and Parker. 

 Here, from the standpoint of a collector, the insect is extraordinarily 

 abundant. I estimated that from 10 to 20 per cent of the bushes were 

 infested and the individual infestations were heavier than elsewhere. 

 All other points I estimated that probably not more than 2 or 3 per 

 cent of the bushes were infested at all. 



Here, then, should be the points at which the commercial recovery 

 of the lac should be possible, if it is possible at all. Attempts to 

 gather a large quantity of the substance for experimental purposes 

 soon showed the futility of any such hope. I seriously question that 

 one could gather fifty pounds of well infested twigs in a day. Of this 

 probably not more than a pound, if as much, would be lac. And lac 

 retails at 75 cents a pound. 



It is further to be noted that the area in which the insect is at 

 present most abundant is quite limited, being confined to a narrow 

 belt on each side of the Colorado River. Even were the insect 

 sufficiently abundant in this region to make its gathering profitable 

 the area thus favored is entirely too small to yield any very large 

 supply. 



Whether the insect could be artificially propagated is another 

 question. To answer it would involve a long series of costly experi- 

 ments that in all probability would likewise yield negative results. 



INSECT PROBLEMS OF WESTERN SHADE TREES 



By Frank B. Herbert, Scientific Assistant,^ Los Gatos, Cal. 



A forest insect laboratory was established at Los Gatos, California, 

 in the fall of 1916, with Mr. H. E. Burke in charge, the object being 

 to study the insect problems of shade trees and ornamental shrubs, 

 with general instructions from the Washington office to first get 

 acquainted with the local shade tree problems and then the larger 

 problems of the Pacific Coast. 



In this work and region a somewhat different class of insects is 

 encountered from those found in the forest and most of them require 

 very different methods of control. There are, of course, some wood 

 and bark-borers which do considerable damage to shade trees, but 

 by far the majority of the pests are scale insects. 



' Branch of Forest Entomology, Bureau of Entomologj', U. S. Department of 

 Agriculture. 



