50 



THE MONTHLY BULLETIN. 



lice prove as destructive to the tree and often more so than do those 

 commonly observed above ground, but their work is often unknown 

 to the orchardist. 



In the spring the over-wintering lice give birth to young which 

 mature in about ten days and which continue to repeat the process of 

 bringing forth living lice until thousands appear upon the trees. How 

 many of the aerial lice winter in the soil and how many of the root 

 lice appear above ground in the spring is not known, but there are 

 probably some which migrate in this manner. 



Fig. 39. — Apple twigs showing tlie work of tlie woolly 

 aphis, Eriosoma lanigera (Hausm. ). (Original.) 



Distribution. — In practically every section where apples are grown 

 in the State. 



Food Plants. — The apple is the favorite food of this insect, though 

 it does also feed upon the roots of the pear trees. The old limbs, 

 young shoots, suckers and roots are attacked. Characteristic knots 

 are produced upon the shoots and others somewhat difit'erent upon the 

 roots, while upon the older limbs great rough enlargements appear 

 and become nearly a foot in diameter and look considerably like a 

 burl. In these -many of the lice spend the winter. ' 



