2(3 The San Juse Scale in Jajjan. 



The San Jose Scale is now so widely distributed all over the empire that 

 no one can draw any sharp line with regard to the life zone ; this is due to 

 the fact that the pest is of rather recent introduction to the various localities 

 where tha infested fruit trees are transferred. But from careful observation 

 we would say that it increases in certain localities more rapidly than in 

 others ; in some localities it will disappear within a few years, because the 

 climate and other conditions are not favorable for its life, although it might 

 survive as at present for a time. Even at an elevation of 1,000 metres as in 

 some parts of Shinano and Hikosan in Kinshiu we found the scale ; but 

 judging from what the writer has observed at such altitudes, it has no great 

 power of modification, simply living there as it was brought on. 



After the actual researches in different localities and long years ex- 

 perience of the writer, ths most favorable condition for the scale life in 

 Japan is on rather low land not higher than 100 metres, surrounded by high 

 hills and protected from severe wind and wath plenty of moisture. 



X. The food plants of the San Jose Ssale in Japan. 



In America the scale has a very wide range of food plants, attacking 

 practically all of the deciduous fruit trees and many of the small fruits ; it 

 can also sustain it-self upon many ornamental shrubs and native trees, except 

 perhaps the Conifers, pine and cedars, and weeds of the field as well as 

 several other plants are also the host. From Dr. E. P. Felt's list of the 

 hosts of the scab, we learn that there are 137 species of plants attacked by 

 the scale, among which 72 are badly infested, and the remaining 65 only 

 rarely attacked. The plants affected by the scale in Japan are much limited 

 in nua^ber ; pear and apple trees are very frequently attacked, and others 

 seldom, the native pear, wild cherry and other trees are free from the pest. 

 The food plants of the scale in Japan known up to the date are given in the 

 following list : — 



1. Fear. (Nashi) 



2. Apple. {Bingo) 



3. Peach. (Momo) 



