i88 AGRICULTURAL ECONOMICS 



helped us in compounding a balanced, complete fertilizer, varying to 

 suit soil conditions and crops. Chemistry, combined with plant- 

 breeding methods, has increased the sugar content of sugar beets by 

 furnishing a method for determining the high sugar content of certain 

 specimens to be used for seed production. It furnishes the basis of 

 much agricultural experimentation and assists in nearly all lines 

 of research. 



The science of zoology has contributed much information of use 

 to agriculture. Perhaps in no way has it been more useful than 

 through the researches on the diseases of domestic animals and the 

 methods oi controlling or mitigating these diseases. The science of 

 entomology, likewise, has been of the utmost utility to farmers in 

 crop production in recent years. Economic entomology may be said 

 to date back for at least two generations. The control of insect pests 

 is perhaps one of the greatest contributions of science to the farmer. 

 A few striking examples may be used to illustrate the success that has 

 been achieved in this line. 



About forty years ago the potato bug or Colorado potato beetle 

 started in to simply eat up or clean up the potato crop of this country. 

 The entomologists readily fixed up a poison to kill him. The codling 

 moth or apple worm was thought by many to originate spontaneously 

 within the fruit. The entomologists have taught us that it is the 

 larva of a harmless-looking little gray moth. They have worked out 

 the life-history of the insect and have given us a spraying routine with 

 arsenical poisons by which practically complete control is maintained. 

 The Hessian fly has been known to destroy half or two-thirds of the 

 wheat crop in the wheat-growing districts. The problem was attacked 

 by the entomologists and the life-history of the insect fully worked out, 

 with the result that a practical, satisfactory remedy was developed, 

 the utilization of which entails no additional expense to the farmer. 

 The remedy consists merely in deferring the planting of the wheat 

 until after the emergence and death of the adult flies. The cotton- 

 boll weevil entered this country from Mexico about twelve years ago 

 and its effects were so severe that it threatened the destruction of the 

 entire cotton industry of the United States. Scientific entomologists 

 attacked the problem vigorously and by means of a thorough investi- 

 gation of the life-history and habits of this pest found a way of getting 

 around it. 



Previous to 1885, the farmer, fruit-grower, or gardener was prac- 

 tically at the mercy of the fungous pests on his crops. The losses are 



