X. THE WOOLLY-LOUSE OF THE APPLE. 



Schizoneura lanigo'a Hausm. 

 Order, Hbmiptera-Homoptera. Family, Aphidid.e. 

 ■ Work op the Insect. 



The injurious work of this insect is not confined to the roots, 

 but it attacks the trunks and branches as well. The injury above 

 ground is especially noticeable on young trees. The woolly aphis 

 is chiefly an apple tree pest, although, as stated later on, it at- 

 tacks other fruit trees as well . 



The presence of the lice is plainly indicated by the woolly ex- 

 cretions. Unlike the peach-tree borer, the woolly aphis does not 

 work its way into the tissue of the plant, but attacks it from the 

 outside only, feeding on the sap which exudes from the punctures 

 made by the minute setae* of the lice. The injurious work upon 

 the roots is very evident soon after the attack is commenced, 

 the infested roots soon becoming covered with galls, as shown 

 a little later on in the illustrations. The injury to the bark and 

 branches is also conspicous. The former frequently become pit- 

 ted or scarred at the points of attack, while the latter wither and 

 die. 



Historical. 



From the evidence at hand it appears that the woolly 

 aphis is probably not a native American species. The 

 earliest records which we have of it show that it was 

 known in Europe in 1787. The species was not given 

 a scientfic name, however, until ISOl, when Hausmann described 

 and named it. At this time it was well distributed in Europe, 

 being especially abundant in the apple orchards of Germany. 

 There seems to be no record of its being generally known in this 

 country previous to 1800. The earliest record which w^e have 

 seen is by Downing, who stated that in 1848 th6 woolly 

 aphis was abundant and destructive to our fruit trees. Promi- 

 nent among the early American writers on entomology who men- 



* Part of tlie month parts. 



