EXPERIMENT STATION BULLETINS. 



569 



THE PEAR PSYLLA. 



{Psylla pyricola.) 



A pest on the pear which promises to become very serious has been 

 found recently in considerable numbers in our State. According to 

 Prof. Slingerland, this insect, the pear psylla, was probably first intro- 

 duced into Connecticut from Europe in 1832. In 1838 it had spread over 

 Massachusetts and part of New York. Since that time it has extended 

 to Illinois and was found in Michigan by Mr. Schwarz before 1891. 

 Recently it has been found in Kent county, where it has done considerable 

 damage. 



INDICATIONS OF ITS PRESENCE. 



The presence of this little pest is usually indicated by a general loss 

 of vitality of the tree early in the season. The young shoots wilt and 

 droop, and by midsummer most of the leaves and fruit fall from the 

 trees. Another indication of its presence is the liquid called honey-dew, 

 which is secreted in large quantities and which spreads over the branches 

 and even falls from them in drops. This sweet liquid attracts many ants, 

 bees, wasps, etc., and often supports a black fungus growth later in the 

 season. 



DESCRIPTION OF THE INSECT. 



Although capable of doing incalculable injury because of the myriads 

 which infest a single tree, the individual insects are very small, measur- 

 ing less than an eighth of an inch when mature and considerably less 

 in the immature stages. The young (Fig. 3) are at first yellow in color, 



Fig. 3. Pear Psylla (Psylla pyricola), younpr 

 (after Slingerland). 



Fig. 4. Pear Ps.vlla (Psylla pyricola), 

 adult (after Slingerland). 



afterward becoming spotted with reddish and black. These little fel- 

 lows hatch from the eggs about the middle of May and immediately 

 commence sucking the sap from the trees, usually choosing the sheltered 



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