PROCEEDINGS 1917 77 



THE DROPPING OF APPLES CAUSED BY SPRAYING WITH 



LIME SULPHUR. 



By G. E. Sanders and A. Kelsall, Dominion Entomological Laboratory, Annapolis 



Royal, N. S. 



DURING THE YEARS 1913 and 1914 the complaint that spraying with lime 

 sulphur had caused the apples to drop, was first heard in the Annapolis Valley. 

 In 1915 the complaint became more general but was not considered as being well 

 grounded, as it was thought that the methods of diluting and using lime sulphur as a 

 summer spray had been thoroughly tested and could not cause the injuries complained 

 of. 



In 1915 Mr. G. L. Thomson, of Berwick, used lime sulphur sp. gr. 1.008 over his 

 whole orchard for the two sprays before, and one spray after the blossoms. In July he 

 used, for the fourth spray, lime sulphur 1.008 sp. gr. on all but two rows of trees. On 

 these two rows he used 3-3-40 Bordeaux. Where the Bordeaux was used there were 

 easily three times as many apples per tree as where the lime sulphur was used. This in- 

 dicated very strongly that lime sulphur used as a fourth spray in Nova Scotia could 

 cause a reduction in the number of apples produced. Fortunately we were able to get 

 data from two of our experimental orchards the same year, on two varieties of apples, 

 Early William and Wagner, which showed that in both cases lime sulphur used after 

 the blossoms as a coarse driving spray, would reduce the quantity of fruit produced. 



In going through the literature available on spraying a few extracts which have 

 more or less bearing on the subject of lime sulphur injury and on the results obtained 

 during the past three years in Nova Scotia are here quoted. 



In Bulletin 262 of the N. Y. Agr. Exp. Sta. (Geneva), Jan. 1905, P. J. Parrott, S. A. 

 Beach and F. A. Sirrine in commenting on the results of using home boiled 15-15-50 

 (wine gallons) lime sulphur wash as a pre-blossom spray state, "The average yield of the 

 sprayed Greenings was 694 apples and the unsprayed 1529. The average yield of the 

 sprayed Baldwins was 1952 apples as compared with 3404 on the unsprayed trees. 

 While recognizing the fact that there may be considerable variation in the amounts 

 and regularity of fruit production for individual trees it is believed that a good portion of 

 the difference noted between the sprayed and unsprayed trees is to be attributed to the 

 effect of the sulphur sprays — the apples from the sulphur treated trees were on the aver- 

 age of better color and larger size than those from the trees which had not received such 

 treatment. 



In Bulletin 369 of the Cornell University Agr. Expt. Sta., Reddick and Crosby 

 give the yield from trees sprayed with 1 to 40 and 1 to 33 lime sulphur as compared with 

 trees not sprayed. In six out of the seven orchards the unsprayed trees gave a greater 

 number of apples than the sprayed (See Proc. Ent. Soc. of N. S. No. 2, 1916 p. 19). 



In Bulletin 347 of the N. Y. Exp. Sta. (Geneva) A comparative test of Lime Sulphur 

 Lead Benzoate and Bordeaux mixture for Spraying Potatoes, F. C. Stewart and G. T. 

 French state, "Neither lead benzoate nor lime sulphur can be profitably substituted for 

 Bordeaux mixture in the spraying of potatoes. Both lack the stimulative influence pos- 

 sessed by Bordeaux and besides, lime sulphur has a tendency to dwarf plants and lower 

 yield." 



The experiments carried on over several years at Geneva show clearly that lime 

 sulphur checks the growth and checks the manufacture of plant food or starch in the 

 potato leaf as is shown in the decreased yield following its use. In connection with 

 dwarfing, the same authors quote, "Dr. H. S. Reed (The Country Gentleman 77:7 

 Jan. 27th, 1912) says: "In the spring when certain varieties (of apple) are tender they 

 may be dwarfed by the spray. This is usually done by application before the trees 

 bloom. Lime sulphur is especially likely to cause dwarfing of leaves." In the spring 

 Mr. P. J. Parrott called our attention to a pronounced dwarfing of early formed apple 



