CHAPTER XII. 



DESTRUCTIVE INSECTS. 



INSECTS are among the most formidable enemies to success- 

 ful fruit-culture. The losses occasioned by the plum curculio 

 alone amount to more than a million of dollars annually. 

 Orchardists are sometimes deterred, by the attacks of this in- 

 sect, from attempts to raise the apricot, nectarine, peach, and 

 plum ; and the market supply of apples and pears is often much 

 disfigured by it. The apple-worm, or codling-moth, is even a 

 more formidable insect pest. New York fruit-growers alone 

 yearly furnish $2,500,000 worth of apples and $500,000 worth 

 of pears to feed this insect; and other similar apple-growing 

 States report nearly as large an annual loss from its ravages. 

 The depredations of many other insect pests, like the apple- 

 tree and the peach-tree borers, the canker-worms, the tent- 

 caterpillars, the apple maggot, and the pear psylla, each 

 causes annual losses amounting to several hundred thousand 

 dollars. 



As a general rule those remedial measures are of little 

 value, which attempt merely to repel insects without destroy- 

 ing them* Experiments show that rarely is an insect repelled 

 from attacking any part of a plant by the application of odor- 

 ous substances, like carbolic acid, tar, etc. 



How insects eat. Another very important fact which fruit- 

 growers must understand is that all insects do not eat in the 

 same manner. Many, like the currant worms or the plum 

 curculio, have two pairs of horny jaws, which they work from 

 side to side and bite off or chew and swallow solid particles 

 of their food ; while several of our worst fruit-pests, like the 

 scale-insects or pear psylla, have mouth-parts built on an en- 

 tirely different plan. Their jaws are modified into long, fine 



160 



