BULLETIN No. 223. 



SPRAYING EXPERIMENTS AND STUDIES ON 

 CERTAIN APPLE DISEASES IN 1913. 



W. J. AIORSE. 



In spite of the fact that a large amount of work has been 

 done both in this and in other countries, in studying the effects 

 of different insecticides and fungicides upon the trees them- 

 .^elves and their efficiency in controlHng the various insect and 

 fungous pests, the ideal spray or combination O'f sprays 

 for use on apple orchard's has not yet been discovered. 

 It is true that with the introduction of lime-sulphur some of 

 the previous difficulties have been eliminated, but at the same 

 time there are others of equal importance which have arisen 

 or which have not been overcome. This is particularly the 

 case under the climatic conditions which exist in the apple 

 growing regions of the northeastern portion of the United 

 States and the adjacent parts of the Dominion of Canada 

 where apple scab frequently appears in its most virulent form. 



While it is granted that lime-sulphur, as ordinarily used, has 

 been found to be less likely to produce spray injury many 

 orchardists maintain that in practical work it is less efficient 

 with them than bordeaux mixture in controlling apple scab. In 

 fact a prominent apple grower from the famous Annapolis 

 valley of Nova Scotia recently told the writer that even with the 

 most careful and thorough spraying with lime-sulphur their 

 fruit the past season was badly attacked by scab and that many 

 orchardists were seriously considering going back to bordeaux 

 mixture again next year. On the other hand it has been the 

 writer's experience that with varieties susceptible to spray in- 

 jury lime-sulphur is, on the whole, by far the most satisfactory 

 material. 



