10 THE SAX .JOSE OE CHINESE SCALE. 



first sign of infestation is found. Fi^iit orowers and others interested 

 have come to accept this conchision and are facing the San Jose-scale 

 problem as one to be regularly dealt with, as with other established 

 insect enemies of fruits. .The range of food plants of this scale is so 

 great that local extermination is out of the question, and it is recog- 

 nized as useless to destrov orchards or new stock because of sliofht 

 infestation. The San Jose scale will have so soon ofained foothold on 

 many ornamental and wild plants that such destruction of orchards 

 would be of no avail, and new stock would be very quickly reinfested 

 from near-by soiu'ces. 



ORIGIN OF THE 12^'SZCT. 



The San Jose scale was tirst established in this country in the early 

 seventies at San Jose, Cal., in the grounds of Mr. James Lick.' 



Following the studies of Professor Comstock of this pest in Cali- 

 fornia in 1880. efforts have been made to determine whence the original 

 infestation came; in other words, to locate the native home of this 

 insect. The importance of discovering the origin of this scale arises 

 from the now well-known fact that where an insect is native it is nor- 

 mally kept in check and prevented from assuming any very destructive 

 features, or at least maintaining such conditions over a veiy long time, 

 by natural enemies, either parasitic or predaceous insects or fungous 

 or other diseases. Mi . Lick, in whose orchard the scale first appeared, 

 was a great lover of plants, and imported trees and shrubs for the 

 ornamentation of his ofrounds fi*om foreiofn countries, and it was verv 

 naturally inferred that in some of these importations he had intro- 

 duced this insect. Before this investigation started, however. Mr. 

 Lick had died, and it was impossible to trace his importations. That 

 the scale was not European in origin was e\'ident; otherwise it would 

 undoubtedlv have come to this countrvlono- before with the numerous 

 importations of stock from Europe. Its original home was therefore 

 naturally placed in some eastern country. In the course of the inves- 

 tigation it was found that the San Jose scale occurred in the Hawaiian 

 Islands, in Chile, in Japan, and in Australia.*' In the case of the 

 Hawaiian Islands it was conclusively shown, however, that it had been 

 carried there on stock from California. The evidence relating to Chile 

 and Australia was of a similar nature — namely, that it had come to 

 those countries comparatively recently on imported stock. Its occur- 

 rence in Japan was not discovered until 1897, and the evidence was far 

 from beinff conclusive that it was indig-enous in that countrv: never- 

 theless the belief that Japan was the source of this scale came to be 

 rather generally accepted. The objections to it were voiced by Doctor 

 Howard and the writer in an article read before the Association of 



aSee BnL No. 3, new series, Dir. Ent., U. S. Dept. Agric, pp. 10-12, 1896. 



