218 



FEU IT INSECTS 



The Pear Psylla 



Psylla pyricola Forster 



This serious enemy of the pear was introduced into Connecti- 

 cut from Europe about 1832. It is now generally distributed 

 over the Eastern states and Canada, extending southward to 

 Virginia; it also occurs in California. Locally the abundance 

 of the pest varies greatly from year to 

 year ; severe outbreaks lasting over two 

 or three years are usually followed by 

 longer periods of comparative immunity. 

 Badly infested trees take on a sickly 

 appearance early in the season, the leaves 

 turn brownish or black, dry up and fall 

 in midsummer ; the fruit remains small 

 and much of it falls prematurely. Some 

 orchards give the impression of having 

 been swept by fire, and owing to their 

 weakened condition are especially liable 

 to winter killing. 



The adults hibernate on the trunks 

 in crevices and under flakes of bark, and 

 when very abundant they may collect 

 under leaves and trash on the ground. 

 The adult psylla has been aptly likened 

 to a diminutive cicada or dog-day harvest-fly (Fig. 201) ; 

 they are about j\ inch in length, dark reddish-brown in color, 

 with the abdomen banded with black. When at rest the two 

 pairs of large, nearly transparent wings slope roof-like over 

 the sides of the body. 



With the first warm days of spring the adults emerge from 

 their winter quarters and egg-laying begins in a few days. 

 The yellowish-orange eggs, about g^ inch in length are deposited 



Fig. 201 .— The pear psylla, 

 adult ( X 20) . 



