I. The Pear Psylla.* 



Psylla pyricola Forster. 



During tlie past five years this minute insect has inflicted such 

 severe losses upon pear growers in various parts of the country 

 that it threatens to seriously interfere with the successful cultivation 

 of this fruit. 



Its History, Distribution and Destructiveness. 



The insect is an old offender, and like most of our other 

 imported insect pests, it has wrought much more destruction here 

 than in Europe, its native home. It was probably first introduced 

 into this country upon young pear trees imported from Europe in 

 1832 by Dr. Ovid Plumb, of Salisbury, Conn. ; f during the next 

 five years he lost several hundred trees frora its ravages. By 1848, 

 it had spread into Massachusetts and into Dutchess and Columbia 

 counties in New York. It is not again recorded as injurious until 

 1871, and then in Illinois ; this State seems yet to be the western 

 limit of its range. In 1879, it was destructive at Ithaca and at 

 Saratoga, N. Y. A dozen years passed witliout any record of its 

 injury. Then, in 1891, it suddenly appeared in enormous numbers 

 in restricted localities in quite widely separated portions of this and 

 other States, and thousands of dollars worth of fruit and many 

 valuable trees were ruined by its ravages. Pear orchards at Fitch- 



* This insect was discussed in detail in Bulletin 44, issued in October* 

 1892. There was so great a demand for the bulletin that the issue was 

 exhausted in about a year. While this discussion includes an abstract of 

 Bulletin 44, it also contains much new material, especially in regard to the 

 distribution of the insect, its natural enemies, and to the methods of fight- 

 ing it. 



tThe evidence submitted by Dr. Lintner (Ninth Kept. p. 319) to show 

 that this insect " may have been operating in the State of New York as 

 early as in 1824, if not in the preceding century," is far from conclusive. 



