71 



fresh stone-lime were boiled together for forty-five minutes, to make 

 a strong solution, and this was then diluted with cold water to make 

 fifty gallons. This "home-made" was compared with the "Rex" 

 lime-sulphur solution of the Rex Company, of Nebraska, one part 

 of which was used with eleven parts of water ; with Scalecide, made 

 by the B. G. Pratt Company, of New York, one part to twenty of 

 water; and with the Target Brand Scale Destroyer made by the 

 American Horticulture Distributing Co., of West Virginia, one part 

 to twenty of water. 



These insecticides were applied with an Eclipse No. 6 pump 

 carrying two leads of hose and 10-foot extension-rods. Each of the 

 extension-rods was provided with a double Vermorel nozzle. The 

 spray barrel was thoroly cleansed when the change was made from 

 one insecticide to another. New nozzle caps having an aperture of 

 about three-fourths mm. diameter were used, caps showing any wear 

 being discarded. A constant strong pressure was maintained on the 

 pump so that the spray was finely divided, "singing" as it left the 

 nozzle. The various insecticides were applied in as thoro, uniform, 

 and fair a way as possible. 



In Orchard No. I the home-made lime-sulphur wash and the Rex 

 lime-sulphur solution were applied to plots 2 and 3, November 19, 

 1907; the Target Brand and Scalecide on plots 4 and 5, November 

 23. The same plots were treated in the same way a second time 

 March 11 and 12, 1908. Plots 7 to 10 inclusive, of Orchard No. II, 

 were sprayed November 24, 1907, and plots 11 to 14 inclusive were 

 sprayed March 12 and 13, 1908. 



FINAL GRADING 



October 5, 1908, all the trees in these orchards were graded a 

 second time by Mr. Flint and Mr. Smith. Mr. Smith knew nothing 

 of the details of the experiment. Altho Mr. Flint assisted in spraying 

 the trees in November, 1907, he was not in the orchards again until 

 the final grading of the trees, and the stakes which marked the plots 

 had in the meantime been removed. 



Results of Treatment. — The results of a spraying operation may 

 be stated in a way to compare the condition of the experimental plot 

 at the time of spraying with its condition after the lapse of a season 

 has made it possible to spray again. The ratio of these two stages 

 of infestation, the original and the final stage, I have called the ratio 

 of improvement or the ratio of loss or gain. If there is a check plot 

 in the series, the rate of progress of its infestation during the season 

 may be used to show the stage of infestation which the experimental 

 plot would have reached if no spraying had been done, and the 

 original infestation of this plot may be compared with this theoretical 

 final stage, so ascertained. The ratio of these two stages I have 



