Suggestions about Spraying. 257 



BRIEF NOTES ON THE SAN JOSE SCALE. 



The San Jose scale has already become so widely distributed that 

 its discovery in new and unexpected localities ought not to occasion 

 surprise. And yet, when in the spring of 1897 it was discovered on 

 the horticultural grounds of this station, it was a matter of consider- 

 able surprise to those who were directly interested in the case. As 

 soon as the fact of its presence was known, active measures were 

 taken to dispose of the pest and the record of the experience of the 

 past season constitutes the substance of the following notes. 



Its occurretice at Cornell. — Whence came the scale to us, no one 

 knows ; the time of its coming is equally obscure. It was first dis- 

 covered during the past spring on dwarf apple trees which had been 

 set some five or six years. When first observed the scales were found 

 in almost innumerable numbers; so thick were they that the bark was 

 completely covered in places. These trees were at once rooted up 

 and burned, a procedure which we have since regretted. An exami- 

 nation of some shrubs of Cornus Baileyi, which were growing close 

 to the apple trees, revealed the presence of the scales in great num- 

 bers. The insects were later found upon small shrubs of Pyrus nigra 

 and Pyrus Aria. 



The first impression was that it came to us on the dwarf apple 

 trees, but these had been under very close observation for a year or 

 two, and if the scales had been present then, it seems hardly possible 

 that they could have escaped notice. The fact that they were found 

 upon a bush of Cornus Baileyi somewhat removed from the other 

 affected plants seems to give some support to the supposition that the 

 scales came on them and spread to the other species. This seems 

 improbable, however, since all of the plants of cornus came from the 

 wild along the shores of Lake Michigan. 



The mystery is the greater when we take note of the fact that all of 

 the affected shrubs and trees have been growing in their present loca- 

 tion for five or six years. It is not unhkely that the scale was with 

 us for some years before its discovery, and on account of some favor- 

 able condition or combination of conditions during the summer of 

 1896, a rapid multiplication took place, and its presence became con- 

 spicuous. See picture on title page. 



