APPLE INSECTS — BUDS AND FOLIAGE 



79 



resume their normal looping ]K)sitions or ascend their ropes 

 somewhat sailor-fashion. 



The male canker-worm moths have fully (levelojxMl win<»;s, 

 while the females are practically wingless, only short stubs of 

 wings being ])resent. This lack of wings ren(l(M\s it nec(\ssary 

 for the females to crawl up the trees to lay t lunr eggs, and affords 

 an opportunity to apply certain effective barrier remedial 

 measures (Fig. 80). The moths are active only at night, 

 and often ascend the trees in the greatest numbers between 

 7 P.M. and 10 p.m. 

 We have seen hun- 

 dreds of the females 

 ascending a single 

 tree during the eve- 

 ning in a badly in- 

 fested orchard ; they 

 are little disturbed 

 by lights brought 

 near. Many of 

 them often secrete 

 themselves in the 

 crevices of the bark 



during the day. There are striking and easily discernible 

 structural differences between the spring and the fall canker- 

 worms in all four stages of their life-cycles. 



The spring canker-worm is common in Canada and in the 

 northern United States from Maine westward to Kansas, thence 

 southward through the Mississippi Valley to Texas. It also 

 occurs in California. It is the species most often destructive 

 in apple orchards, especially in its western range. The moths 

 practically always emerge in early spring, sometimes during 

 warm spells in February, but usually in March and April. 

 They may continue to go up the trees for from 6 to 10 weeks. 

 We have reared male moths varying in wing expanse from f to 



Fig. 81. — Spring canker-worm, male moth (X 2). 



