Report of the State Entomologist. 311 



multiplied and more ample means for their control were required, insecticides, so-called, 

 were discovered. Twenty years ago, when a beetle, whose home was in the Eocky 

 mountains, had, at the approach of civilization, abandoned its wild Solanum food-plant 

 for the more nutritious cultivated one, and was rolling eastward over the Western 

 States as steadily and irresistibly as a tidal wave, the timely discovery by a citizen of 

 Illinois that Paris green was an effectual remedy for it, at once brought under control 

 the ravages of the devouring pest, and made the continued cultivation of the potato a 

 possibility. Ten years thereafter, London purple, a residuum in the manufacture of 

 analine dyes, was found to be almost equally efficacious against the Colorado beetle, 

 and, as the fruit of experiments since conducted, we have now in these two arsenical 

 compounds, insecticides effective against nearly all of the mandibulate insects which 

 feed exposed on such vegetable substances as we or our domestic animals do not require 

 for food. 



The need of reaching the large order of suctorial insects which are not affected by the 

 arsenites, led to the discovery of kerosene as a destroyer of insect life. It was found to 

 be fatal to every insect to which it could be applied. As in its undiluted state it is also 

 fatal to vegetation, means were sought, and were speedily found, for reducing it to any 

 desired degree. Often as the methods of preparation of what are known as " kerosene 

 emulsions " have been published in our agricultural and horticultural journals, it may 

 be of service to you to give the most approved method, in a single short sentence : 



The best emulsion for general use is produced by violently agitating through the rose 

 of a force-pump until emulsified in a homogeneous mass, two gallons of kerosene to one 

 gallon of a hot soap solution, made by dissolving a half-pound of common soap in a 

 gallon of water. 



The ordinary dilution of the above emulsion for use, is with nine gallons of cold water. 



Of the various other insecticides with which the fruit grower will find it to his advant- 

 age to be familiar, as hellebore, pyrethrum, carbolic acid, coal-tar, tobacco, etc., I will 

 not speak, but will refer you to publications in which they are fully discussed, and 

 which constitute a part of that literature of economic entomology which should find 

 place in the library of each one of you. 



Publications Eelating to Fkuit Insects. 



The advance made in our knowledge of dealing with insect pests, is largely due 

 to the investigations and discoveries of the Entomological Division of the Department 

 of Agriculture, at Washington, of which Professor Riley is chief. The publications of 

 this division present full reports of experiments in testing almost every material that 

 has from time to time been recommended as an insecticide, even to ice water and buck- 

 wheat flour ; descriptions of various devices, implements, and machines for applying 

 insecticides ; descriptions, figures, and life-histories of our most formidable pests, with 

 the best remedies or preventives against them, and much other valuable matter on 

 entomological subjects. 



Of these publications — of primary value are the Annual Reports of the Entomologist 

 (by Professors Riley and Comstock), of the series commencing with the establishment 

 of the Division in 1878. In addition to a limited number of these reports issued as 

 separates, they are included in the Annual Report of the Commissioner of Agriculture; 

 and as the immense edition of four hundred thousand copies of this report is printed by 

 Congress each year, certainly every one desirous of obtaining a copy should have no 

 difiiculty in procuring it through application to his representative in Congress or to the 

 Commissioner of Agriculture. The same volume will also contain hereafter the annual 

 report of the Pomologist, the Mycologist, and the Botanist, of the Department. 



The Entomological Division has also issued, from time to time, Bulletins, containing 

 observations and experiments in its practical work, and studies and reports on special 

 insects of exceptional importance. Bulletin No. l was published in 1883 ; No. 15, the last, 

 in August of the present year. Application for these should be made to the Department 

 of Agriculture. 



