30G IvEPOET OF THE DEPARTMENT OF ENTOMOLOGY OF THE 



fruit is checked. The usual " June drop " fails to occur and the 

 apples do not increase in size but cling tightly to the twigs, forming the 

 " cluster " apples so familiar to fruit-growers. (Plate XXII, Fig. 2.) 

 Continuous breeding of large numbers of the insects aggravate the 

 injuries and the leaves become tightly curled, discolored and thickly 

 coated with honeydew. During prolonged outbreaks the injured 

 leaves turn brown and drop, causing more or less extensive defolia- 

 tion. Fruits that have escaped earlier attacks from the lice become 

 stunted, or deformed, or the epidermis may become ruptured. 

 (Plate XXI, fig. 2.) Fruit which reaches a good size may be ren- 

 dered worthless from a coating of the honeydew. 



The attacks of the woolly aphis result in spongy swellings on the 

 roots and on the smaller twigs and branches. (Plate XXII, fig. 3.) 

 On the branches these galls crack, forming favorable entrance places 

 for injurious fungi and for other insects. (Plate XXII, fig. 4.) The 

 roots of young trees may be killed if the galls are abundant. Trees 

 weakened by aphis attacks enter the winter in a poor condition and 

 are liable to injury by low temperatures. 



DESCRIPTION OF INSECTS AND LIFE HISTORY. 



The green apple-aphis. — The eggs of this species are laid during 

 October and November on succulent twigs, in crevices in the bark 



or at the bases of the buds. These eggs (Fig. 40) 

 are minute oval bodies about one seventy-fifth 

 of an inch in length and of a greenish color when 

 deposited but later they become shiny black, 

 in which condition thej^ remain until hatching 

 occurs in the spring. As the buds begin to 

 expand during the latter part of April the 

 young lice hatch and make their way in large 

 numbers to the green ends of the opening buds. 

 The newly hatched aphids (Plate XXllI, fig. 2) 

 are very small oval bodies about one-fiftieth of 

 an inch in length. At birth the insects are of 

 a very dark, green color but become lighter as 

 they attain full size. These individuals are all 

 females and when fully developed (Plate XXIII, 

 fig. 6) give birth to living young aphids which be- 

 come viviparous females. (Plate XXIII, fig. 5.) 

 As opportunity is afforded the insects work into the interior of the buds 

 and seek the protection given by the hairy growth of the unfolding 

 leaves. The numbers of the lice increase rapidly and in a comparatively 

 short period of time the buds, foliage and blossoms are thickly covered 

 by the pests. The aphids are at first wingless, but about the first of 

 June in Western New York, or two weeks later in the more northern 

 apple districts, winged females (Plate XXIII, fig. 4) appear which 

 migrate to other trees and extend the area of infestation. Winged 

 and wingless females continue to appear on the trees throughout the 



Fig. 40. — Eggs of green 



apple-aphis. 



(Much enlarged.) 



