74 



scales louiid ;ilive ;it the time of tre;ituient. At the bottom of each 

 table is a series of data for the entire lot of trees, corresponding- in 

 form to those in the l)i>ily of the table ft^r each tree, 



}\ \ \'\\\< 1 M UN PA I. 1 >inv\ 1 i.s . 

 /')'/::/ Lot of y /"<■<•>. (\iliforniii Wash. 



Nine apple-trees sprayed with lime, sulphur, and salt on the 3d 

 day of March. Weather partly clouily, with colil raw wind from 

 the east-tunthcast, teiiipiMature ,>l) at 7 a. m. ami 40^ at noon. 



Dead ami liviuij' scales were first counteil on these trees the 

 following- ilay, March 4. Although the fact was not known at the 

 time, it became apparent later, bv ci)mparison of percetitai^es ot 

 scales on these trees with those found i>n check trees anil on other 

 lots counteil before insecticide treatnu>nt, that m> iliscoverable etlect 

 i>f the insecticide had been produccil at the time this first count 

 was maile. If any scale insects had been killeil so soon, their ap- 

 pearance had not yet sutVuiently chanjied to indicate the fact. The 

 percentaj^es foutul on this tirst day are consequently to be taken as 

 iiulicatin*^- the r.itio, before treatment, of dead and liviuij- scales 

 amons; the voung- of the preccdiiiii- year. One thousand three lum- 

 iheil .itul titty such scales were countcil in all, aiul .-^^ per cent, of 

 these were alive, 4S per cent, havitii; died trom unknown causes, 

 in most cases probably from drouth. 



In ileterminitii; the etfect of the insecticiile under the varying- 

 conditions supplieil, this tirst count of living- scales was made the 

 starting- point for the calculation of the percentag-es of scales killed; 

 that is, if only 5>i> per cent, of the scales were found alive it the 

 beginning of the experiment, the destruction of scales by the in- 

 secticide was figured on this 5i> per cent., those deail in the begin- 

 ning being- of course ig"nored. Counts wore made upon carefully 

 selected specimen twigs or branches, the number counted each time 

 varying from lOt^ ti> 4.000. and the totals for each tree, from .^lU) to 

 5,40tK The total number of scales counted from this lot on nine 

 trees was 24,t)t)0. 



The etTect of the insecticide was only gradually made mani- 

 fest, and was not fully produced during the period of continuous 

 observation which ended on the -5«th of March. This fact was not 

 understood at the time but was made apparent by the result of the 

 visit of May 1-. as shown in the last column but one of the table 

 for Lot 1. 



As these various trees were treated subsequent to the insecti- 

 cide spray bv an ai>plication of various amounts of water at ditler- 

 ent intervals, it will be necessary to discuss each tree separately. 



