No. 4.] THE SAN JOSE SCALE. 385 



THE SAN JOSli! SCALE. 



(Aspidiotits perniciosus Com.) 



BY PROF. C II. FERNALD, ENTOMOLOGIST TO THE BOARD. 



History and Distribution. 



The San Jose (San Ho-sa') scale insect first made its ap- 

 pearance in California not far from 1870, but it is not known 

 from what country it came, though it is now known to occur 

 in Chili, Australia and Hawaii. It increased rapidly till 

 1873, when it had become so abundant on the fruit trees at 

 San Jose as to seriously injure them, and received the com- 

 mon name of the San Jose scale. 



It was first technically named and described from Santa 

 Clara County, California, by Prof. J. H. Comstock, in the 

 report of the Department of Agriculture for the year 1880, 

 page 304, under the name Aspidiottis perniciosus, " The 

 Pernicious Scale." After describing it, Professor Comstock 

 says : ' ' From what I have seen of it, I think that it is the 

 most pernicious scale insect known in this country ; cer- 

 tainly I never saw another species so abundant as this one 

 is in certain orchards which I have visited. It is said to 

 infest all the deciduous fruits grown in California, excepting 

 the peach, apricot and the black tartarian cherry. It attacks 

 the bark of the trunk and limbs as well as the leaves and 

 fruit. I have seen many plum and apple trees upon which 

 all the fruit was so badly infested that it was unmarketable." 

 Since Professor Comstock wrote the above, the insect has 

 been found on apricot and peach as well as other plants. 



In 1882 it had extended into all the fruit-growing districts 

 of California, and has since that time been distributed over 

 the country more or less widely, and is now known to occur 

 in Oregon, Washington, British Columbia, Idaho, Nevada, 

 Arizona, New Mexico, Missouri, Indiana, Florida, Virginia, 

 Maryland, Pennsylvania, New Jersey, New York and Massa- 



