79 



strong- northwest wind; temperature, 30" at 7 a. m. and 45'' at 

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

 sample twig-s and branches from a part of the trees just before the 

 application of the insecticide, and from another part on the follow- 

 ing- day. The ratios of dead to living scales were practically iden- 

 tical in these two lots, thus showing, as has been already re- 

 marked, that scales killed the first day, if any, do not sufficiently 

 chang-e in appearance within that time to suggest the fact. Sub- 

 sequent counts of scales were made for this lot on thirteen later 

 dates, the number counted, as before, ranging from one hundred to 

 five hundred, and amounting for the lot to 11,500 specimens. 



Tree No. ./. — An apple-tree, sixteen feet high, with a nine- 

 inch trunk and a twelve-foot top; in fair condition, but badly in- 

 fested by the scale. This tree received but one water treatment, 

 and that on the 7th of March, two days after the insecticide appli- 

 cation and on the same day as the first light fall of rain. ?"*ifteen 

 gallons were applied, and approximately two g-allons must be added 

 for the rainfall. Scales alive in the beginning-, 42 per cent.; 83 per 

 cent, of these dead on the sample for the fifth day, and but (»8 per 

 cent, on that for the twentieth day. August 20, two hundred 

 scales examined, all dead. 



T?'ce No. Jo. — A peach-tree twelve feet high, with a six-inch 

 trunk and a nine-foot spread of top; in very poor condition, though 

 but moderately infested by the scale. No water except the natural 

 rainfall. Forty-seven per cent, of the scales were alive in the begin- 

 ning; 92 per cent, of these were dead on the thirteenth day, when 

 the first subsequent count was made, and 98 per cent, on the 

 sample for the twentieth day. 



yVce No. 27. — An apple-tree, fifteen feet high, with an eight- 

 inch trunk and a seventeen-foot top; in g-ood condition, moderately 

 infested with the scale. This tree was sprayed with water but 

 once, and that five days after the insecticide application. Thirty- 

 six per cent, of the scales were alive in the beginning; 62 per cent- 

 of these were dead on the fourth day, 80 per cent, on the fifth and 

 88 per cent, on the twentieth. Aug-ust 20, one hundred scales ex- 

 amined: all dead. 



Tree No. 2(j. — An apple-tree, twelve-feet high, with a seven- 

 inch trunk and a fifteen foot top, in bad condition, and heavily in- 

 fested. Twice treated with water, once on the fifth day after the 

 insecticide spray and once on the tenth, in each case with fifteen 

 gallons. Forty-two percent, of the scales alive at the beginning 

 of the experiment; 80 per cent, of these dead on the fourth day, 

 92 per cent, on the tenth day, and 93 per cent, on the twentieth. 



