77 



twelfth; ratio of scales finally killed, 100 per cent. Of five hundred 

 scales examined Aug^ust 20, none were alive. 



Tree No. y. — An eig-hteen-foot tree with an eight-inch trunk 

 and a ten-foot top; in poor g-eneral condition, moderately infested 

 by the scale. Fifteen g-allons of water on the thirteenth day after 

 insecticide treatment, and another fifteen g-allons on the fourteenth; 

 before this, only the rainfalls already described. This tree and all 

 the remaining trees of this lot were practically check trees with 

 regard to the effects of the water sprays, since these were applied 

 after the full effect of the insecticide must have been produced. 

 Sixty-eight per cent, of the scales alive in the beginning; 80 per 

 cent, of these dead on the fifth day, 83 per cent, on the seventh, 

 and 92 per cent, on the twenty-first. Of five hundred scales exam- 

 ined August 20, none were alive. 



Tree No. S. — Seventeen feet high, with an eight-inch trunk 

 and a twelve-foot top; in fair general condition, but badly infested 

 with the scale. But one application of water, and that fifteen 

 gallons on the fourteenth day after insecticide treatment. Fifty- 

 four per cent, of scales alive in the beginning, and 54 per cent, of 

 these dead on the third day; 90 per cent, dead on the sample repre- 

 senting the fifteenth day, and 91 per cent, on the twenty-first. Of 

 four hundred scales examined August 20, none were alive. 



yVec No. (). — A sixteen-foot tree, with an eight-inch trunk and 

 an eleven -foot 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 begin- 

 ning; 83 per cent, of these dead on the fifth day and 87 per cent, 

 on the twelfth; final effect^ May 12, 99.6 per cent, destroyed. Of 

 one hundred scales examined August 20, none were alive. 



Iree No. lo.—A fifteen-foot tree, with a seven-inch trunk and a 

 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; 77 per cent of 

 these dead on the third day and 95 per cent, on the sixth, with a 

 final result of 99.4 per cent, destroyed by May 12. Of seven hun- 

 dred scales examined August 20, none were alive. 



Taking the entire group of nine trees together, without refer- 

 ence to differences of treatment subsequent to the insecticide spray, 

 it appears that an average of 52 per cent, of the scales were alive 

 in the beginning; that 67 percent, of these were dead by the third 

 day, 82 per cent, by the fifth, and 86 per cent, by the sixth; and 

 that the final average effect of the treatment was the destruction 



