2 BULLETIN 838, U. S. DEPARTMENT OF AGRICULTURE. 



Monterey cypress. The insect is extremely difficult to control — a 

 fact which makes it a very disagreeable and harmful pest. 



HISTORY. 



The cypress bark scale was first described in 1911 as Sphaero- 

 coccus cupressi by Mr. E. M. Ehrhorn x who collected it at Niles and 

 San Jose, Calif., as early as 1903, and at Belvedere, Calif., in 1908, 

 in the bark crevices of Monterey cypress. The next mention of this 

 insect was in the report of the Selby Smelter Commission in 1915, 

 when Mr. J. W. Blankinship 2 and Prof. R. W. Doane 2 reported it as 

 one of the factors causing the death and dilapidation of the Mon- 

 terey cypress in the Selby smoke zone. In October, 1918, Mr. G. F. 

 Ferris, 3 with the writer's approval, erected a new genus, Ehrhornia, 

 for this species, for it certainly was not a Sphaerococcus. Although 

 an important shade-tree pest, no discussion of this insect has ap- 

 peared in print otherwise, except for a short note by the writer 4 on 

 its damage and distribution. 



This coccid has no synonyms, having been listed under the name 

 Sphaerococcus cupressi until the new genus, Ehrhornia, was erected 

 in 1918, with cupressi as the type. 



NATIVE HOST PLANT. 



This scale insect could not be found at Cypress Point or Point 

 Lobos, Calif., the only localities where the Monterey cypress is 

 native, which showed quite conclusively that this tree was not the 

 native host. 



On November 9, 1917, the cypress bark scale was found infesting 

 some planted trees of Arizona cypress (Cupressus arizonica) at San 

 Jose, Calif., although it has not at the present writing been found 

 on the native cypress in Arizona. 



On December 6, 1917, this insect was found by the writer infesting 

 one incense cedar (Libocedrus decurrens), and later several more 

 trees, on the Stanford University campus. Later, the native incense 

 cedars at Placerville, Calif., were examined. A number of them 

 were found infested. They were several miles from any planted 

 cypresses, which, moreover, were not infested. 



Later, the cypress bark scale was found upon incense cedar at 

 Ashland, Oreg., by Mr. Albert Wagner, of the United States Bureau 

 of Entomology; at Crockers, Calif., by Mr. G. F. Ferris; and at 



1 Ehrhorn, E. M. new coccid;e with notes on other species. In Can. Ent.. v, 

 43, no. 8, p. 275-280. (Figs. 3, 3a, b, c.) 1911. 



2 Holmes, J. A., Franklin, E. C, Gould, R. A. report op the selby smelter com- 

 mission. U. S. Dept. Int., Bur. of Mines, Bui. 98, p. 381-397 ; 428-450. 1915, 



3 Ferris, G. F. notes on coccidm II. In Can. Ent. v. 50, no. 10, p. 323-332. 1916. 



4 Monthly Letter of the Bureau of Entomology, U. S. Dept. Agr., no. 46, p. 5. 

 February, 1918. 



