516 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



color and covered with a white, waxy secretion, given off in threads 

 from the abdomen so as to form a cottony mass over the colony. 

 These females produce from 2 to 20 young per day, which 

 become full grown in from eight to twenty days according to 

 Alwood,* 100 or more probably being produced in two weeks. 



FIQ. 445. The woolly apple-aphis: at left, colonies on twig and in scar 

 on an apple limb; at right, crown and root of young apple tree, showing 

 characteristic swellings produced by the root aphids. (After Alwood.) 



Reproduction continues on both tops and roots except as checked 

 by the cold of winter, the aphids becoming most abundant in 

 midsummer. Early in the fall a generation of winged aphids 

 appears, which migrates to other trees. They are about one- 

 twelfth inch long and have a wing expanse of one-quarter inch. 

 They appear to be black, but the abdomen is really a dark yel- 

 lowish or rusty brown color when closely examined, and bears 

 more or less of the waxy secretion on the tip. Each of these 

 winged females gives birth to from four to six wingless males and 



* Bulletin 45, Va. Crop Pest Commission, p. 12, Special Bulletin, Va. 

 Agr. Exp. Sta. 



