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The American Garden. 



Vol. XI. 



JULY, 1890. 



No. 7. 



THE OUTLOOK FOR ECONOMIC ENTOMOLOGY. 



I HE PAST twenty years 

 have been very fertile 

 with practical results 

 in the warfare against 

 insects. Not only does 

 this period include a 

 remarkable advance in 

 our knowledge of the 

 life-histories of pests, 

 but it is distinguished 

 by the discovery of 

 far-reaching remedies and the true beginning of 

 national investigations. Many obstacles have been 

 overcome, and the economic entomologist is to-day 

 prepared by this work to offer fairly satisfactory 

 remedies for a great majority of our most promi- 

 nent insect pests. Many problems yet remain un- 

 solved, however, and work upon these will engage 

 the best energies of our workers in this branch of 

 agricultural science for many years to come. They 

 include, among other things, the improvement of 

 remedies already known, and of insecticide appli- 

 ances, together with the investigation of the new 

 insect enemies to agriculture, which are, in our com- 

 paratively new country, constantly making their 

 appearance, either from change of habit or of food- 

 plant of some hitherto innocuous species, or from 

 the importation of species from other countries. 



All late advances in the study, and all probable 

 advances in the immediate future, come under 

 three chief categories : 



1. The ascertaining of every detail in the life 

 history of species at present injurious or likely to 

 become injurious. 



2. Thorough and careful experiment with insecti- 

 cide substances. 



3. The invention and improvement of apparatus 

 for the application of insecticides. 



(I) The first of these three categories is fully as 

 important as the last two, since upon the careful 

 performance of the work indicated depends the 

 question of prevention and of ridding ourselves of 

 our enemies by natural means. It even influences, 

 in a potent degree, the proper application of insecti- 

 cides, thus underlying and forming the basis for 

 work in the second and third categories. 



Take the case of the codlin moth, for example. 

 Had we not learned by careful examination that the 

 larvff, leaving wind-falls, crawl back to the trunk 

 of the tree in order to find proper places for spin- 

 ning their cocoons, and leaving apples before they 

 have fallen, crawl down the limbs to seek the rough- 

 er bark of the trunk, the admirable bandage rem- 

 edy, our principal means against this pest before 

 the use of arsenical sprays had proved safe and 

 satisfactory, would never have come into use. The 

 discovery of the applicability of the sprays them- 

 selves was to a certain extent empirical ; yet a 

 knowledge of the egg-laying method and of the 

 habits of the newly-hatched larv^ at once explains 

 its applicability and proves to the cautious man its 

 theoretical efficacy. 



Take another and perhaps even more striking ex- 

 ample : From 1874 to 1878 the thick-thighed 

 walking-stick, an insect which had previously been 

 considered harmless, did a great deal of damage to 

 shrubbery and forest trees in Yates county, N. Y., 

 completely defoliating the hickory and oak timber. 

 So many acres were infested by the insects in large 

 numbers that the application of arsenical poisons 

 was practically out of the question ; but a study of 

 the life-history of the insect disclosed a safe and 



COPYRIGHT, 1890. 



