230 Aqrioultctbal Experiment Station, Ithaca, N. T. 



this enemy becomes formidable and very destructive when the 

 conditions are favorable for the reproduction m countless 

 numbers. 



The Past History of This Pest. 



The pest is an old offender; and its recorded history in this 

 country shows that it has been present for many years in or near 

 most of the localities above noticed. The insect was probably 

 first introduced into this country upon young pear trees miported 

 from Europe in 1832, by Dr. Ovid Plumb, of Salisbury, Conn. Dr. 

 Plumb fii'st noticed the insect in 1833; and during the next five 

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

 when the pest was first brought to the notice of an entomologist. 

 Dr. HaiTis, it had spread into Massachusetts and into Dutch^'ss 

 and Columbia counties, in New York. In 1879, W. S. Barnard 

 observed the pest in destnictive numbers at Ithaca and at Sara- 

 toga, N. y. 



The earliest record we have of its appearance further west is 

 in 1871, when Dr. LeBaron recorded a severe attack upon young 

 pear trees in Illinois. JSIr. E. A. Schwartz has found the insect 

 in Michigan. Professor J. B. Smith, of New Jersey, has been 

 unable to find it in that State, and we have no record of its 

 occurrence further south. 



It is thus seen that the pest is quite widely distributed over 

 the northeastern portion of the United States and has reached the 

 Mississippi valley in its westward progress. The severe outbreak 

 of 1891 indicates that the insect has been increasing in numbers. 

 It has apparently reached a point, in New York State, at least, 

 where it only awaits favorable opportunities, in meteorological 

 conditions possibly, to repeat its ravages of last year in unex- 

 pected localities. Pear growers should be watchful and prepared 

 to fight it early in the season. 



Its Classification. 



This pear pest is one of the true bugs belonging to the sub- 

 order Homoptera, family Psyllidae, commonly known as jumping 

 plant-lice, from the leaping habit of the adult. Their general 

 name, Psylla, is the Greek word, meaning a flea. The Psyllid 



