162 



DESTRUCTIVE INSECTS. 



beginning with those affecting the roots, then the trunk and 

 bark depredators, following with those feeding on the buds 

 and leaves, and finally discussing those which infest the fruit. 

 The insects which affect the pear, plum, peach, cherry, quince, 



grape - vine, currant and 

 gooseberry, raspberry and 

 blackberry, and strawberry 

 will be discussed in the 

 order in which they are 

 named, and in each case 

 the method outlined for 

 the apple insects will be 

 followed. 



The Woolly Aphis (Schizo- 

 neura lanigera}. This red- 

 dish - brown plant - louse, 

 covered with a flocculent 

 waxy secretion (Figs. 211 

 and 212) works both on 

 the roots, where it forms 

 knotty enlargements (Fig. 

 210), and on the branches, 

 where it causes roughened 

 scars. It attacks the apple 

 only, and some varieties, 

 the Northern Spy, for in- 

 stance, are quite immune 

 from it. Nursery stock 

 and young trees are often 

 seriously damaged, while 



FIG. 210. FIG. 211. 



The Woolly Aphis. 



FIG. 210. Root 

 by the aphis. 



illustrating deformation j n most parts Q f the coun _ 

 FIG. 2ii. Portion of root 



with aphids on it. FlG. 212. The Root 



try well-established bear- 

 Louse, female. Figs. 210 and 211 natural ing trees are rarely notice- 

 size ; Fig. 212 much enlarged. (U. S. Div. ftbl in j ured> It has quite 

 of Entomology.) J J . ^ 



a complicated life-history. 



Most of the lice are wingless, but in the fall many winged 

 forms appear, and these are one of the means by which the 

 insect is spread. It is also widely distributed on nursery 

 stock. 



Th aerial or branch form of the insect does little injury, 



