50 STATE POMOLOGICAL SOCIETY. 



larger amount of arsenate of lead used alone, and lime-sulphur 

 — the efficiency being in the order named. It should not be 

 forgotten that one pound of dry arsenate was added to each 

 50 gallons of Bordeaux mixture and lime-sulphur used. This 

 smaller amount of the arsenate when used alone reduced the 

 amount of scab from 39 to less than 16 per cent. Therefore, it 

 is more than a possibility that this insecticide added to Bordeaux 

 mixture and lime-sulphur may materially contribute to the fun- 

 gicidal effect of the combined spray. 



A large amount of fruit russeting was experienced in 1913, 

 apparently due to natural causes. This was considerably 

 increased by the action of some of the sprays. \\'ith Bordeaux 

 mixture and lime-sulphur this increase amounted to 40 and 1 1 

 per cent respectively, while it was actually less on the plot 

 sprayed with the larger amount of dry arsenate of lead than 

 on the check. On account of the last mentioned fact the relative 

 value of the arsenate of lead spray was still more apparent that 

 season. About 12 per cent more perfect apples were obtained 

 with it than where standard dilution lime-sulphur was used. 



Neither in 1914 nor in 191 5 did scab develop sufficiently to 

 give a rigorous test of the fungicidal properties of arsenate of 

 lead. In scab control in 1914 two pounds of dry arsenate of 

 lead in 50 gallons of water fell about three per cent behind lime- 

 sulphur containing one-half this amount of the insecticide, but 

 the per eent of merchantable apples zvas practically the same. 

 In 191 5 the combined lime-suli)hur spray gave a fraction of 

 one per cent better scab control, but on account of russeting only 

 about 90 per cent of the apples were merchantable. In contrast 

 with this, because of freedom from russeting. the larger amount 

 of arsenate of lead used alone gave over 97 per cent of the same 

 grade of fruit. 



Do not misunderstand me. I have not reached the point 

 where I am ready to recommend that Maine orchardists depend 

 entirely on arsenate of lead to control both apple scab and chew- 

 ing insects. I am not yet ready to advise that such action be 

 taken with regard to the Highmoor orchards. I prefer to take 

 a much more conservative attitude and suggest that the possi- 

 bilities of arsenate of lead as a spray for scab are well worth 

 looking into. The figures obtained during the past four years 

 are as given and are certainly very suggestive. Time can only 



