512 ANNUAL RJEPORT OF THE Off. Doc. 



TREES COVERED. 



By striking an average of reports as to number of trees of different 

 ages that may be thoroughly covered with 100 gallons of spray, we 

 find that a reasonable exception is : 



250 one year old trees. 

 150 five year old trees. 



70 ten year old trees. 



25 fifteen years old trees. 



10 old trees. 



The above refers to apple only. The number of peach trees would 

 correspond with apple of an equal size. Working out a per tree cost 

 from the above data, we find that the spraying of a one year old 



apple tree will cost about, $.012 



Five year, 02 



Ten year, 045 



Fifteen year, 125 



Old tree*, 31 



We ai'e confident that good sprayers can lower this estimated 

 cost; but believe the average as shown is very close to what may be 

 generally expected. 



CODLING MOTH SPRAYING. 



Of those reporting on this important work, 45 per cent, used a 

 commerciji.l combination of Eordeaux and arsenate of lead, 10 per 

 cent, used home-made Bordeaux and Paris green, 10 per cent, home- 

 made Bordeaux and arsenate of lead, 10 per cent. Paris green only, 

 25 per cent, arsenate of lead only. The superiority of arsenate 

 of lead over Paris green as a poison for codling moth is brought 

 out very strongly, an average of the reports of two growers who 

 used Paris green showing that 20 per cent, of picked fruit and 35 

 per cent, of drops were wormy as against almost perfect results 

 from arsenate of lead. This result is, of course, partly due to 

 rainy weather which washed off the Paris green and did not disturb 

 the arsenate of lead. This, however, only emphasizes another ad- 

 vantage of arsenate of lead. In the table of cost comparisons which 

 follows, the commercial Bordeaux-arsenate of lead was used at a 

 strength of 10 pounds to 100 gallons. The home-made Bordeaux 

 lead arsenate was made with four pounds arsenate of lead, eight 

 pounds copper sulphate and ten pounds lime to 100 gallons of water 

 and ]*aris green at the rate of eight ounces to 100 gallons of water. 



COST OF MAKING 100 GALLONS DILUTE SPRAY. 



Commercial Bordeaux — arsenate of lead, 

 Home-made Bordeaux-arsenate of lead, 

 Home-made Bordeaux— Paris green, 



Average of above 



