27 



increase in size ten tliousaud times. To reach this remarkable 

 growth a man at his maturity would have to weigh forty tons."* 



In view of such facts it will be seen that insects, by reason of 

 their enormous multiplication and great voracity, may become 

 more dangerous to crops if unchecked than larger and more power- 

 ful animals. 



It may be truthfully said that this country suffers far more from 

 the depredations of insects than any other ; and this is to be 

 expected, in view of the methods employed in agriculture, and 

 the conditions under which it is here conducted. 



A considerable proportion of the fertile land in America is still 

 uncultivated, and there are vast tracts in which insects can breed 

 unmolested until they exhaust their feeding grounds and overwhelm 

 the surrounding country, as in the case of the migratory locusts. 

 In the settlement and development of a new country man at once 

 begins to disturb the long-established relations between living or- 

 ganisms. In a wooded country the forests are cut off, the larger 

 birds and mammals are exterminated or driven away, and great 

 disturbances occur in the economy of nature as a consequence of 

 these changes ; new plants are introduced and with them new insect 

 pests are brought in from other regions or from foreign countries. 

 As civilization advances large areas are devoted to special crops, 

 like the great grain farms of the north-west, the orange groves and 

 vineyards of California, and the great orchards and potato fields 

 of other States. These tracts offer great quantities of desirable 

 food and thus stimulate the reproduction of insects to a remark- 

 able degree. The spread of imported species to the very confines 

 of civilization is accelerated by an ever-increasing traffic on newly 

 constructed highways and railways, and as these imported insects 

 escape most of their natural enemies by being brought to this 

 country, and find more favorable conditions awaiting them here, 

 their fecundity and destructiveness are increased in undue propor- 

 tion even to their increased food supply. Such are the cabbage 

 butterfly, the wheat midge, the Hessian fly, the gypsy moth and 

 others. Native species which were harmless to agriculture under 

 natural conditions in the wilderness sometimes take advantage of 

 the introduction of a new and succulent food plant and follow it 

 back from the frontier into the agricultural regions, spreading over 

 the whole country and causing wide-spread injury to a staple crop, 

 as did the Colorado potato beetle. As the land becomes settled 

 and the ravages of insects increase, the settlers, instead of endeavor- 



* Annual Report New Jersej' State Board of Agriculture, 1888, p. 295, " Our 

 Insect Enemies," by J. A. Lintner, Ph.D., N. Y. State Entomologist. 



