Appendix. 167 



successive days immediately following the insecticide application with 

 fifteen gallons of water on each day, the second of these treatments coin- 

 ciding with the first day of rain. Forty-two per cent of the scales alive 

 in the beginning; thirty-eight per cent of these dead on the second day, 

 and ninety-two per cent on the fifth, the average final result being the 

 destruction of ninety-three per cent of the scales — to be compared with 

 eighty-seven per cent finally destroyed on the companion tree, No. 33, 

 treated with the California wash. 



Tree No. 26.^ — A twelve-foot peach tree, with a six-inch trunk and an 

 eleven-foot top; in very poor condition though but moderately infested. 

 Treated, like No. 36 of the second lot, with fifteen gallons of water on 

 the day following the insecticide application, and another fifteen gallons 

 on the ninth day thereafter, that is, the fifteenth day of March. This 

 last treatment coincided with the third rainfall. Thirty-three per cent 

 of the scales alive at first; thirty-five per cent of these dead on the 

 second day, sixty-eight per cent on the fourth, eighty-four per cent on 

 the fifth, and ninety-three per cent on the fifteenth — when the next suc- 

 ceeding count was made. A general final average of ninety-two per cent 

 of the scales destroyed. The companion tree of the second lot gives a 

 ratio of ninety-seven per cent finally killed. 



Tree No. 28. — A fourteen-foot peach tree, with a five-inch trunk and 

 a ten-foot top; in very poor condition, though but moderately infested 

 with the scale. This tree was reserved as a check upon the experiment, 

 without water treatment of any kind, comparing in this respect with No. 

 20 of Lot 2. Fifty-eight per cent of the scales were alive on it in the 

 beginning: seventy-six per cent of these were dead on the fifth day, and 

 ninety-one per cent on the tenth, the final average destroyed being ninety- 

 one per cent. The corresponding ratio for the companion tree of the 

 previous lot was ninety-five per cent. 



Tree No. 30. — A twelve-foot apple tree, with an eight-inch trunk and 

 a fourteen-foot top; in good condition, and but moderately infested. 

 Treated but once, and that with thirty gallons of water on the next day 

 after the application of the insecticide. Forty-four per cent of the scales 

 alive in the beginning; ninety-two per cent of these found dead on the 

 sample examined on the fifth day after treatment, the final average ef- 

 fect being the destruction of eighty-nine per cent of the scales. On tree 

 No. 31, corresponding to this in the second lot, the average final ratio 

 was eighty-four per cent destroyed. 



COMPARISON' OF VALUES OP OREGOX AND CALIFORNIA WASHES. 



Comparison of Lot 3 with the companion trees similarly treated in 

 Lot 1 brings out very definitely the relative advantage of the Oregon 

 wash. The general average of the ratios of final destruction is ninety- 

 three per cent for the Oregon wash and eighty-seven per cent for the 

 lime, sulphur, and salt. If we limit the comparison to the three pairs 

 of trees which received the water treatment within the first five days after 

 the application of the insecticide, that is, to Nos. 1, 2, and 3 of Lot 1, and 



