Appendix. 159 



Tree No. 9. — A sixteen-foot tree, with an eight-inch trunk and an eleven- 

 ioot top; in fair condition, but badly infested. No water (except rains) 

 until the fourteenth day, when thirty gallons were applied. Fifty-six per 

 cent of the scales alive in the beginning; eighty-three per cent of these 

 dead on the fifth day, and eighty-seven per cent on the twelfth; average 

 final effect, eighty-nine per cent destroyed. 



Tree No. 10. — A fifteen-foot tree, with a seven-inch trunk and thirteen- 

 foot top; in fair condition, moderately infested. No water was applied 

 to this tree, and the effect of the insecticide was modified only by the 

 natural rainfall already referred to. Sixty-nine per cent of the scales alive 

 in the beginning; seventy-seven per cent of these dead on the third day 

 and ninety-five per cent on the sixth, with a final average result of ninety- 

 five per cent destroyed. 



Taking the entire group of nine trees together, without reference to 

 differences of treatment subsequent to the insecticide spray, it appears 

 that an average of fifty-two per cent of the scales were alive in the be- 

 ginning; that sixty-seven per cent of these were dead by the third day, 

 eighty-two per cent by the fifth, and eighty-six per cent by the sixth; 

 and that the final average effect of the treatment was the destruction of 

 eighty-six per cent. 



Second Lot of Trees. California Wash. 



Nine trees, partly apple and partly peach, sprayed with lime, sulphur, 

 and salt on the fifth of March. Weather clear, with fairly strong north- 

 west wind; temperature, thirty degrees at seven a. m., and forty-five 

 degrees at noon. In this case the dead and living scales were counted on 

 sample twigs and branches from a part of the trees just before the ap- 

 plication of the insecticide, and from another part on the following day. 

 The ratios of dead to living scales were practically identical in these two 

 lots, thus showing, as has been already remarked, that scales killed the 

 first day, if any, do not sufficiently change in appearance within that time 

 to suggest the fact. Subsequent counts of scales were made for this lot 

 on eleven later dates, the number counted, as before, ranging from one 

 hundred to four hundred, and amounting for the lot to ten thousand five 

 hundred specimens. 



Tree No. 4. — An apple tree, sixteen feet high, with a nine-inch trunk and 

 a twelve-foot top; in fair condition, but badly infested by the scale. This 

 tree received but one water treatment, and that on the seventh of March, 

 two days after the insecticide application and on the same day as the first 

 light fall of rain. Fifteen gallons were applied, and approximately two 

 gallons must be added for the rainfall. Scales alive in the beginning, 

 forty-two per cent; eighty-three per cent of these killed on the sample 

 for the fifth day, with an average of seventy-eight per cent as the final 

 effect of the insecticide. 



