CHAPTER V. 



INSECTS INJURIOUS AND BENEFICIAL TO AGRICUL- 

 TURE. 



ECONOMIC ENTOMOLOGY relates to those insects which 

 prey on our crops; it comprises a study of their habits, 

 classification, and the remedies against their attacks; it also 

 includes a study of insect-parasites of the domestic animals, 

 of man himself, as well as household pests. In short, this 

 branch of applied science treats of the habits and best 

 means of destroying any insect which is in any way in- 

 jurious to human interests. To succeed well in this applied 

 science one must be a close, patient observer and of a prac- 

 tical turn of mind. 



The number of injurigus insects in the United States is 

 large and increasing. Owing to the destructiveness of in- 

 troduced species,* the large areas devoted to special crops, 

 and other causes, crops in this country seem far more liable 

 to insect-depredations than in the Old World, and the evil 

 is perhaps especially felt in the more recently settled por- 

 tions of the country. 



Prof. J. A. Lintner, the State Entomologist of New York, 

 in his first report remarks: " There is probably not a single 



* The most obnoxious insects brought accidentally from Europe 

 are the following: the wheat-midge and Hessian fly; currant-worm 

 (Nematus venlricosus), oyster-shell bark-louse, apple Aphis, hop-louse, 

 grain Aphis, and several other species of plant-lice; the coddling- 

 moth, cabbage-butterfly (Pieris rnp<t>}, cabbage moth (Ephestia inter- 

 puntella), currant-borer (Algeria tipuliformis], asparagus-beetle, clover- 

 root borer, onion-fly (Phmbia ceparuni), and several other root-flies; 

 also some of our cut-worms appear to have been introduced from 

 Europe. 



On the other hand, we have unwittingly sent to Europe the grape 

 Phylloxera. 



