20 maine agricultural experiment station. 



Green Apple Aphid. 

 (Aphis pomi De G.) 



The body is pear-shaped., the colors being yellowish green, 

 greenish, or darker, varying considerably in detailed markings 

 and in the several generations. 



Winter eggs (fig. 30) are deposited by the sexual females in 

 the fall. They hatch in the spring, and, like the species next 

 considered, the aphids developing from them cause a curling 

 of the leaves. The green apple aphid infests the apple through- 

 out the year. Upon the hatching of the winter eggs in spring 

 a succession of agamic generations is produced, the earlier ones, 

 except the first, with numerous winged individuals which 

 migrate to other trees and establish new colonies. 



Rosy Apple Aphid. 

 (Aphis sorbi Kaltenbach.) 



The rosy apple aphid is readily distinguished from the pre- 

 ceding by its larger size, rounder body, and usually rosy color, 

 which, however, may vary from salmon to tan or even to slaty 

 gray or black, the body being covered with a whitish pulverul- 

 ence. 



Winter eggs are deposited in the autumn by sexual females, 

 and more often on the trunk and larger limbs than with the 

 other species mentioned. They hatch in spring as the apple 

 leaves are pushing out, and the young aphids infest the young 

 leaves and later the tender shoots and foliage, the latter thus 

 becoming usually badly curled. Three generations from the 

 egg are said to occur on the apple in the spring, many individ- 

 uals of the second and third generations developing wings and 

 migrating to other trees and to other host plants. After the 

 third generation the apple is deserted by the insects until fall, 

 when the return migrants appear and give rise to the true sexual 

 forms, the females depositing eggs as described. 



METHODS OF CONTROL. 



Pruning. — As has been stated, the aphids under considera- 

 tion pass the winter in the egg stage on the apple, the eggs being 

 deposited more or less promiscuously over the more nearly 



