12 THE SAN 'jOSE OK CHUSTESE SCALE. 



acre to 2 or 3 acres in extent. These are trained low on over- 

 head trellises (PL HI), and at a short distance look like vineyards. 

 There are several districts v\'here such orchards occur in considerable 

 numbers. These orchards are very ancient, many of them having 

 trees more than one hundred 3'ears old. If the San Jose scale were 

 native to Japan it would occur in these pear orchards, the pear being 

 one of the favorite food plants of this scale insect. 



In northern Japan, including the island of Hokkaido, and the northern 

 end of the main island, Hondo, apple raising has been introduced in 

 modern times very much on the lines followed in this country. Prior 

 to the opening of Japan to foreign commerce and exploration the 

 apple as an edible fruit was unknown in that countrv. The orchards 

 in northern Japan are chief!}", therefore, of American origin and rep- 

 resent American varieties. Most of the stock came from California, 

 and much of it was undoubtedly infested with San Jose scale when it 

 was received. There is, therefore, thruout these northern apple 

 orchards a mild infestation with this scale. The Japanese are very 

 enthusiastic in their efforts to gain all the benefits of western civiliza- 

 tion, and this is shown in horticultural as well as in other fields. The 

 three leading nurseries, therefore, of Japan have been very active dur- 

 ing the last twenty or thirt}" years in importing the different varieties 

 of pear, peach, and apple from America, and all three of these nursery 

 districts have become infested with San Jose scale, evidently from such 

 importations from California, where the scale has been wideh^ dis- 

 tributed for thirt}^ A^ears. Outside these nurseries, however, in cen- 

 tral and southern Japan, the San Jose scale did not occur, except where 

 it had been introduced on new stock from the nurseries referred to. 

 The old native pear orchards were free from scale, except where 

 replants had been made of American varieties, or new native stock, to 

 fill in breaks in the orchards. The infestation was very often just 

 beginning and immediatelv surrounded the replants. In all Japan, 

 therefore, in the little house gardens and temple grounds where were 

 cherry, plum, and other trees suitable for San Jose scale, this insect 

 did not occur, except where the evidence was verv plain of its recent 

 introduction as indicated. Without going into details of the evidence, 

 it is sufficient to say that the conditions in Japan are essentiall}" the 

 same as in this country. The San Jose scale is a recent comer. It 

 was, in fact, not known in Japan prior to the year 1897, when its 

 presence there was first determined, but it has now been scattered 

 pretty widel}^ by nursery stock, exactlj^ as in this countr}^ and occurs 

 under similar conditions; in other words, onh^ where it has been 

 recently" introduced. The investigation showed very distinctly that 

 Japan could not be considered responsible for the San Jose scale. 



The results and conclusions arrived at by the writer were after- 

 wards fully confirmed b}" a ver}" thoro and painstaking explora- 



