70 



alive on this tree when the treatment beg-an. Three days after, 75 

 percent, of these had been killed, and five days after, 84 per cent. 

 The samples taken on the twelfth and nineteenth days showed an 

 extraordinary percentag^e of living scales, — 2(> per cent, on each 

 day,— and the average ratio of scales killed by May .12 stands at 

 100 per cent. August 20, four thousand scales were examined, of 

 which all but nineteen were dead, the living scales being found 

 only on the lower branches which penetrated an adjacent infested 

 hedge. 



V)rc iVo. 2. — A sixteen-foot tree, with a nine-inch trunk and 

 an eighteen-foot top; in fair g-eneral condition, but badly infested 

 with the scale. Treated with water but once, and that on March 

 4, the day succeeding the application of the insecticide spray. 

 Rainfall of course followed on the 7th, 11th, and 15th, as on all 

 other trees of this experiment, amounting- to about fifteen g-allons 

 of water additional. Thirty-seven per cent, of the scales alive at 

 the time of treatment; 78 per cent, of these dead three days after; 

 and 8() per cent, dead on the twelfth day. The final effect was the 

 killing- of 98.9 per cent, of the scales. August 20, two thousand 

 scales examined were all dead. 



Trrr jVo. ,\ — An eig-hteen-foot tree, with an eight-inch trunk 

 and a thirteen-foot top; in good general condition, but badly in- 

 fested. Water treatment three days after the insecticide applica- 

 tion, and twice on alternate days thereafter, making- forty-five 

 gallons of water thus applied. Twenty-nine per cent of the scales 

 alive when the treatment began; 53 per cent, of these dead on the 

 third day and 79 per cent, on the seventh; the final destruction of 

 scales, 98.6 per cent. Of two hundred scales examined Aug-ust 20, 

 none were alive. 



Vrcc No. 5. — A fifteen-foot tree, with an eight-inch trunk and 

 an eleven-foot top; in poor condition, badly infested. Sprayed with 

 fifteen gallons of water five days after treatment, and again two 

 days later. Forty-seven per cent, of the scales alive in the beg-in- 

 ning-; 80 per cent, of these killed by the sixth day, when the first 

 count was made, 90 per cent, by the twelfth, and 94 per cent, by 

 the 22d day. Of two hundred scales examined August 20, none 

 were alive, 



7)rr /Vo. 6.— A fifteen- foot tree, with an eig-ht-inch trunk and 

 a twelve-foot top; in poor condition, moderately infested by the 

 San Jose scale. Treated but once with water, and this on the sev- 

 enth day after the insecticide spray, when thirty gallons were up- 

 plied. Sixty-four per cent, of the scales alive in the beginning-; 84 

 per cent, of these dead by the sixth day and 8(» per cent, by the 



