DESTRUCTIVE INSECTS. 171 



green or other poisonous spray in the spring to control this 

 serious pest ; it is usually necessary to make two thorough ap- 

 plications before the blossoms open. 



Canker-worms are among the most destructive of apple pests. 

 They are measuring-worms from an inch to an inch and a half 



Fig. 233.— Spring Canker-worm. — Larva; female ; male. 



in length, and finally develop into small moths, the females 

 of which (Fig. 233) have no wings. There are several differ- 

 ent kinds of canker-worms, and they often work together in 

 the same orchard. They consume the foliage, except the larger 

 leaf veins, and give the trees a scorched appearance from a 

 distance, so that the insects are known as "fire-worms" in 

 some localities. We have seen thousands of acres of apple 



Fig. 234.— Fall Canker-worm.— Female; male ; larva. 



orchards in Western New York defoliated by these pests in a 

 single season. They spread rather slowly from orchard to 

 orchard. 



In some localities the kind known as the fall canker-worm 

 {Anisopteryx pometaria) (Fig. 234) is the most numerous, while 

 in other sections the spring canker-worm {Paleacrita vernata) 

 (Fig. 233) far outnumbers any others. At least two other 

 kinds may also occur in injurious numbers; they are the lime- 

 tree winter-moth Hybernia tiliaria, and Bruce 's canker-worm 

 Rachela bruceata. 



