REPORT OF THE ENTOMOLOGIST. 



INTRODUCTION. 



Sir: I have the honor to present herewith my annual report for 

 the year 1886. It is confined to the consideration of a few prominent 

 and important insects that have not before been fully treated of in 

 Department publications, and I have omitted from it, because of the 

 limitation as to number of pages allotted to the Entomologist, many 

 briefer notes and articles that have been prepared as the result of the 

 year's work. These omitted portions will at once be prepared for 

 special bulletins. 



The fruit interests of the Pacific coast have of late years been more 

 and more threatened by injurious insects, and in the present report 

 the leading place is given to the consideration of the Cottony Cushion- 

 scale {leery a purchasi), which is perhaps the greatest pest that the 

 fruit-growers in that section have to contend with. I was urged last 

 spring by many prominent horticulturists and by Hon. W. W. Mor- 

 row, M. C. from the fourth district of California, to personally visit 

 the infested region, but as this was impossible then on account of 

 impaired health and important duties in the East, Messrs, D. W. Co- 

 quillett and Albert Koebele were sent to Los Angeles early in the year, 

 with instructions to carry on through the summer an extensive series 

 of experiments and observations upon the species. It will be seen 

 from the context that this is one of those insects which have, naturally, 

 extremely limited powers of spreading, and that its introduction from 

 one continent to another and its subsequent spread might easily have 

 been prevented had vigilance and intelligent appreciation of the dan- 

 gers of such an introduction prevailed in years gone hj as they are 

 beginning to prevail now. The article is supplemented by detailed 

 reports onexperiments by Messrs. Coquillett and Koebele, which indi- 

 cate the difficulties of controlling the pest, but at the same time show 

 that these difficulties may be overcome. 



The kerosene emulsions, in different proportions, which have 

 proved so entirely satisfactory against the scale-insects of the Orange 

 in Florida, have in general failed to win the good opinion of orange- 

 growers in California. Mr. Matthew Cooke and other writers in the 

 latter State have pronounced the kerosene emulsions inferior to caustic ' 

 soda and caustic potash, and even to strong solutions of whale-oil soap. 



Until this year I have been unable to offset the decision of these 

 gentlemen with the result of careful experiment, though I have always 

 believed their want of success was due to imperfect preparation of the 

 emulsions or imperfect application of them. I was also inclined to 

 give some credence to the theory advanced by Prof. E. W. Hilgard, 

 that the dryness of the atmosphere in California induced a more rapid 

 evaporation of the kerosene in the emulsion, which accounte J for its 

 inferior results. Moreover, the Cottony Cushion-scale is much less 

 susceptible to the action of insecticides than any Floridian species on 

 account of the protection afforded by the large waxy mass which it 

 secretes, as well as on account of its great vitality. 



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