81 



Taking thisj^roup of nine trees as a whole and avera^inj^ all 

 statements conccrninf^ them, it appears that 42 per cent, of the 

 scales were alive when the experiment bej^-an; and that S() percent, of 

 these had been killed by the treatment by the second day thereaf- 

 ter, 71 per cent, by the fourth, 84 per cent. \)y the fifth, and H') per 

 cent, by the twentieth. 



On the two trees examined May 12, *).S.f) per cent, of the scales 

 had been killed by the spray, and on the four trees inspected Au- 

 {^ust 20, nolivinf^ scales were found amon^ the seven hundred ex- 

 amined. 



To this lot it will be convenient to add for discussion two 

 other trees sprayed with lime, sulphur, and salt on the 7th of 

 March, which, it will be remembered, was the day of the first 

 rainfall occurring" in the experimental period. These trees re- 

 ceived no water treatment, but were intended as checks on the 

 other experiments. 



Vrcr No. ,\S'. -The first of these was a peach -lr(!e, nine feet 

 high, with a five-inch trunk and a ten- foot to[). It was in excel- 

 lent condition, and only moderately infested. Thirty-eight per 

 cent, of the scales were alive on the day preceding- the insecticide 

 application, and eighteen days after the treatment SS i)er cent, of 

 these were dead. 



Vree JVo.j(j. — The second tree of this pair was also a peach- 

 tree, about nine feet high, with a five-inch trunk and a ten-foot 

 top. It was in excellent general condition, and moderately in- 

 fested, (inly 27 per cent, of the scales were alive when the ex- 

 periment began; 94 per cent, of these were dead by the eighteenth 

 day after treatment. 



(iKNKKAl- l\'l<;SUI,'rS()l'' Mxi'IUVIMK.NTS WITH fvIM)':, Slll.l'ini K , A N I) Sai.T. 



An analysis of the data contained in the above descriptions of 

 Lots 1 and 2 and in the tables of percentages for those lots ena- 

 bles us to distinguish two groups of trees; those which received 

 some treatment of water within five days after the insecticide ap- 

 plication, and those which, if treated with water at all, did not 

 receive it until the seventh day or later. 



There are eleven trees in the first group, namely, 1, 2, 3, 4, S, 

 27, 29, 31, 32, 33, and 36, and nine trees in the second, namely, 6, 

 7, 8, 9, 10, 20, 3.S, 38, and 39. 



The average effect of the insecticide upon the nine trees of the 

 second group was the destruction of 92.1 per cent, of the scales by 

 March 25, and the corresponding destruction on the eleven trees 



