81 



considered in tiie upkeep of apple orchards in ]\Iassaehu- 

 setts. 



Wliile tliese species show differences in habits and 

 structures, thej^ display, from the standpoint of orchard 

 economy, marked similarities in their injurious activities, 

 v.-hieh are briefly epitomized as follows : — The eggs of these 

 iiisects are laid principallj^ during October and November 

 on succulent twigs, in crevices in the bark or at the bases 

 oi buds. In this stage they pass the winter. The following 

 spring, principally during the latter part of April, the eggs 

 hatch and the young aphides make their way to buds in the 

 most advanced stages of development and later work into 

 the interior, seeking protection in the hairy growth of the 

 unfolding leaves and rudimentary blossom structures. 



These creatures, commonly called stem-mothers, mature 

 about the time of the blossoming of the trees. After pro- 

 ducing several generations, the oat aphis first, and later the 

 rosy aphis, leave the apple trees and seek their summer 

 host plants. The green aphis may live on the apple trees 

 all the year, breeding continuously during the summer, pre- 

 ferring water sprouts. 



The ^Vork of the aphides during ]\Iay and June is es- 

 l>ecially destructive since it occurs during the period when 

 fruit buds are forming and when the vigor of the trees is 

 also required for the development of the young apples of 

 the current season's crop. If favorable conditions exist 

 during this period for rapid increase of the pests the leaves 

 become curled and the development of young fruit is 

 checked. With a prolonged outbreak, the injured leaves 

 tarn brown- and drop, causing more or less extensive de- 

 foliation. The fruits fail to increase in size and cling tight- 

 ly to the twigs, forming clusters of small, deformed fruit, 

 commonly known as "cluster apples." 



During some years a good proportion of the crop may 

 hl' affected,' \vhich usually entails a' great financial loss. 

 The chief iriteriest of apple growers in these insects is how 



