CHAPTER XII. 



ENEMIES OF PLANTS. 



In dealing with plants one of the most im- 

 portant problems which arises is how to meet 

 their enemies. In order to do this one must 

 know somethinof of the nature and habits of 

 each particular species which he needs to con- 

 trol. Actual observation of them at work is the 

 best means of obtaining a knowledge of the 

 enemies of plants. But some good work on in- 

 sects and fungi (like those listed at the end of 

 the chapter) should be consulted, or if none of 

 these are at hand, one should write to one's own 

 State Entomologist for advice and literature. 



These enemies may be divided into two great 

 classes: (i) animal forms, (2) plant forms. 

 Among animal forms the most important ene- 

 mies of plants are injurious insects. 



y4.— INJURIOUS INSECTS. 



I. The General Characters of Insects 



in the adult state are one pair of antennae; three 

 body divisions, head, thorax, and abdomen ; 

 three pairs of legs, and two pairs of wings. 



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