76 



it crosses a vertical, the degree of loss or gain for that row, and the 

 figures on the face of the diagram give those degrees precisely. It 

 will be readily understood that if the check plot and the experimental 

 plot were without influence one upon the other — if there had been 

 no movement, that is to say, of the San Jose scale across the dividing 

 line between the plots — then both these transverse lines on the dia- 

 gram would have been virtually horizontal, their inner ends as widely 

 separated in a vertical direction as are their outer ends, substantially 

 as shown by the transverse dotted lines. The oblique part of each 

 line marks the transition zone ; and the upward turn of both lines 

 at the left is an indication of the loss of insects from the outside rows 

 of the check plots. 



Experiments of 1909 



Continuing our operations in the Etherton orchards in 1909, we 

 used for spraying experiments only Orchard II. Orchard I received 

 a single spraying, for the mere control of the scale, March 18-23, 

 1909, with home-made lime-sulphur prepared as in the preceding 

 year. According to the grading of October, 1908, the infestation of 

 this orchard taken as a whole averaged 5 degrees on a scale of 10, 

 and when graded again in January, 1910, its average was 2.39 de- 

 grees, a gain in condition of 52.2 percent within the year as the result 

 of the treatment. 



Orchard II was carefully graded March 11, 1909, and was di- 

 vided into four plots. One was reserved as a check and the other 

 three were sprayed, respectively, with home-made lime-sulphur, lime 

 and sulphur manufactured by the Grasselli Company, and a petro- 

 leum preparation known to the trade as San-U-Zay Scale Oil. The 

 experimental plots were sprayed March 23-25 by Mr. L. M. Smith, 

 assisted by one man and two boys, all entirely inexperienced in such 

 work. Rains fell every day during the spraying, and showers and 

 high winds on the 24th made the work ' ' very unsatisfactory. ' ' Prob- 

 ably on this account, and because of the inexperience of the operators, 

 the results of these experiments were much less favorable than those 

 of the preceding and succeeding years. A second grading, for a 

 comparison of conditions and an analysis of results, was made Janu- 

 ary 17-18, 1910. From the following table it will be seen that the 

 three preparations used were in practically the same class as to 

 results produced, the home-made lime-sulphur, however, falling a 

 little short of the other two. It was an interesting fact that the 

 "miscible oil" preparation applied in March seemed practically equal 

 in value to the solutions of lime and sulphur. 



