maine agricui.tural experiment station. i91o. 337 



2. Rosy Apple Aphis. 

 (Aphis pyri Beyer.) 



The rosy apple aphis, regarded by Gillette as possibly Aphis 

 pyri Boyer, is readily distinguished from the preceding by its 

 larger size, rounder body, and usually rosy color, which, how- 

 ever, may vary from salmon to tan or even to slaty gray or 

 black, the body being covered with a whitish pulverulence. 



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 tgg stage on the apple, the eggs being 

 deposited more or less promiscuously over the more nearly 

 terminal twigs (fig. 30). With young trees especially, which 

 are seen to be heavily stocked with the eggs, the latter may be 

 largely removed during the work of pruning, and the prunings 

 should be collected and burned. 



The insects in the egg condition are frequently distributed 

 on nursery stock; therefore, if in planting trees this stock be 

 well pruned and the prunings destroyed, the establishment of 

 the aphids in young orchards may be often prevented or de- 

 layed. 



Winter spraying for destruction of eggs. — Excellent results 

 have followed the use of lime-sulphur wash, almost all of the 

 eggs of the apple aphis having been destroyed by one thorough 

 application in spring shortly before the buds opened. The use 

 of this wash for the eggs of aphids would also control the 



San Jose scale when present. 



22 \ 



