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N. S. ENTOMOLOGICAL SOCIETY 



ing lime sulphur spraying is the result of derangement, either permanent or temporary, 

 of the chlorophyll of the leaves. 



The extent of damage in the field is well shown by the following: — • 



No. of apples produced per pair of Wagner Trees — 1916. 



Spray used 



Pre-blossom or 2nd spray 

 After blossom 3rd spray . . 

 After blossom 4th spray . . 



Lime sulphur 

 1.009 sq.gr. 



159 



108 



30 



Bordeaux 

 4-4-40 



327 

 204 

 231 



Unsprayed trees averaged 277 apples per pair. 



No. of Apples per Wagner Tree— Sprayed only once, the Fourth Spray 1917. 



Bordeaux 2-8-40 157 apples per tree 



3-3-40 152 apples per tree 



4-8-40 152 apples per tree 



Lime sulphur 1.005 sp. gf 6 apples per tree 



In the large experiment in 1917 the lime sulphur plots each had 12 trees and the 

 soluble sulphur and Bordeaux plots each 16 trees. The variety was Wagner through- 

 out. 



No. of Apples per tree. Only one Spray used in each plot. 



Spray used . . 



First spray. . 

 Second spray 

 Third spray . 

 Fourth spray 



These figures corroborate our previous findings and show that the greatest injury 

 is done by lime sulphur on the fourth or last summer spray, less on the third or after- 

 blossom spray, less again on the second and practically none on the first. 



It is important to note here that the Wagner is one of the varieties that drops its 

 fruit most easily when injured by lime sulphur. The Mcintosh, Gravenstein and Golden 

 Russett are among the varieties least affected while the Blenheim, Ribston, King, 

 Baldwin, and Wagner are among those that are most easily caused to drop. 



It was noted at the beginning of this paper that the first serious and widely distri- 

 buted injury from lime sulphur was noted in Nova Scotia in 1915, that the same injury 

 was even more widely noted in 1916, and all will admit that 1917 surpassed all preced- 

 ing years in Nova Scotia for spray injury. Early in 1917 attention was called by Mr. 

 B. G. Pratt, of New York, to the work of Dr. Stone of the Mass. Agr. College, which 

 showed that spray injury varied inversely with the amount of sunlight that a plant had 

 previous to spraying. In other words, leaves abundantly supplied with chlorophyl 

 were less susceptible to spray injury than those in which the chlorophyll was depleted. 

 We proved this to our own satisfaction by putting apple seedlings in a dark room, oth- 

 ers in a half lighted cellar, and others in full sunlight for a week. These were then all 

 placed outside and some of each group sprayed with lime sulphur, soluble sulphur and 

 Bordeaux, and some of each group left as checks. The lime sulphur sprayed seedlings 



