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SCIENCE 



[Entered at the Post-Offlce of New York, N.Y., as Second-Class Matter. J 



A WEEKLY NEWSPAPER OF ALL THE ARTS AND SCIENCES. 



Ninth Tear. 

 Vol. XVII. No. 414. 



NEW YOEK, Januaey 9, 1891. 



Single Copies, Ten Cents. 

 3.50 Per Year, in Advance. 



THE OUTLOOK FOE APPLIED ENTOMOLOGY.' 



Gentlemen, — You have made it thed^ity of your presiding 

 officer to give an annual address, — a duty the less easy to 

 perform for a new organization than for one which lias a 

 history behind it, and not facilitated by my absence in Europe 

 at the time of your organization. 



I had thrown together a sort of resume of the results ob- 

 tained during the year in economic entomology, more par- 

 ticularly by the entomologists of the different State stations, 

 in the belief that this would be one of the most appropriate 

 themes to pVesent; but when I learned, from his circular of 

 Sept. 15, that Professor Forbes intended covering substan- 

 tially the same ground, and that it was expected of him as 

 one of his duties as chairman of the committee on entomol- 

 ogy of the Association of Agricultural Colleges and Experi- 

 ment Stations, it became evident that what I might present 

 in that direction would be substantially anticipating and 

 repeating what we may expect and hope to hear from him. 

 T will endeavor, therefore, to touch upon a few matters un- 

 connected with station work. 



Some Results from the National Department at Washington. 



The hydrocyanic-acid gas treatment against scale insects is 

 becoming more and more common in California, and has to 

 a certain extent superseded the use of washes, especially 

 against the red scale {Aspidiotus aurantii) . This is largely 

 due to the fact that recent experiments, carried on through 

 Mr. Coquillett, have resulted in a great cheapening of the 

 process. The expense has been reduced to one-third, and the 

 bulky machinery mentioned in my report for 1887 has been 

 for the most part dispensed with. It has also been found 

 that the use of the process at night is safer and more bene- 

 ficial, in that it lessens the effect of the gas upon the foliage. 



The repeated importation of scale-insects from Florida into 

 California has attracted much attention. The species con- 

 cerned are principally the purple scale (Mytilaspis citricola), 

 the long scale (M. gloverii), and the chaff scale [Parlatoria 

 pergandei). The fact that these insects must have been 

 repeatedly imported into the State in past years without 

 obtaining a foothold, has been used as an argument against 

 a quarantine, and a great deal of discussion on the subject 

 has been had in the California papers. From my own ob- 

 servations in the State, I am convinced, that, where the 

 proper conditions of shade and moisture are obtained, there 

 is no reason why these scale-insects should not obtain a foot- 

 hold, but that they will probably die out in the hotter, dryer, 

 and less shaded localities. An agent who was sent to 

 Pomona to investigate certain newly planted orange-groves 

 of Florida trees found, that while the trees were planted a 



' Address of Dr. C. V. Riley at the annual meeting of the Association of 

 Economic Entomologists, Champaign, 111., Nov. 11-14, 1890. 



year previously, and had been dipped, according to custom 

 there, in a caustic solution, every tree examined by him bore 

 a few specimens of the purple scale. The excitement on this 

 subject in California has been fostered by the claims of rival 

 nurserymen engaged either in the importation of Florida 

 stock or dealing in varieties grown at home, and with so 

 many contrary claims from persons prejudiced by their busi- 

 ness interests, it is difficult to extract the truth. A rigid 

 quarantine, not absolutely prohibitive, were wisest, for 

 great injustice might be worked by absolutely prohibitive 

 restrictions. Careful inspection and thorough treatment, 

 if they could be guaranteed, would prove an effective safe- 

 guard, but it were unsafe to trust to them without rigid 

 quarantine. 



I have commenced a series of experiments upon the black 

 scale (Lecanium olece), a species which, ordinarily occur- 

 ring upon the olive, has long damaged citrus fruits in-' Cali- 

 fornia. The horticulturist of the Wisconsin station, Mr. E, 

 S. Goff, has modified the Nixon pump by adding a tube, so 

 that kerosene may be drawn from one receptacle and a 

 mixture of soap and water from another, thus forming a 

 mechanical mixture in the act of spraying. This modifica- 

 tion, at the request of Professor Henry, I have had tried in 

 this series of experiments, and, although it is too early to 

 state the results, it may be said that so little time and labor 

 are required in preparing a stable emulsion, that this me- 

 chanical substitute will probably not come into general use. 

 In this connection it may be observed that the formul» 

 recommended by some of our most voluminous writers are 

 very misleading, and ai-e calculated to produce only a me- 

 chanical mixture more or less unstable. The use of kerosene, 

 temporarily combined with water or soap suds by mechanical 

 means, dates from many years back. It was a favorite 

 remedy of my friend Thomas Meehan, who urged it in 1871 

 in the Gardener^s Monthly; it was experimented with by 

 others; and I used it successfully in 1872 against an unde- 

 scribed Lecanium on Austrian pine, as also against Aphides 

 on the place of Mr. Julius Pitman of St. Louis, and in 1874 

 and 1875 against the congregated young of the Rocky Moun- 

 tain locust. But the true and stable kerosene emulsion which 

 now forms one of the most satisfactory and widely used in- 

 secticides, and which requires two parts of the oil to one of 

 the emulsifying agent, violently churned until a stable, 

 butter-like emulsion results, was the outgrowth of my efforts 

 in the investigation of the cotton-worm, the milk having 

 been first suggested in 1878 by the late Dr. W. S. Barnard 

 while working at Selma, Ala., and the most satisfactory 

 formula in 1880, from experiments which I had continued 

 over two years by Mr. H. G. Hubbard on orange-trees. 



A locust outbreak of some interest has occurred in parts 

 of Idaho and Utah, and has been investigated by Mr. Bruner, 



