SPRAYING EXPERIMENTS AND APPLE DISEASES. 1 3 



of scab was secured with lime-sulphur, particularly the stronger 

 dilution, and the percentage of perfect apples was about double 

 that secured with bordeaux mixture. Hence the results secured 

 during the last season are very much in favor of lime-sulphur. 



"Soluble sulphur." Judging from the results of a single 

 season alone it would seem that this compound is a fairly effi- 

 cient fungicide as far as apple scab is concerned and fully equal 

 m this respect to the standard dilution lime-sulphur as will be 

 seen in comparing the results secured on plots 3 and 5. Un- 

 fortunately, as has already been pointed out on page 7, its 

 use at the rate of 2 pounds to 50 gallons of water produced 

 very severe leaf injury. Based on our own experience and 

 that of others during the past summer, which latter is given 

 under another heading, "Soluble sulphur," used with arsenate of 

 lead at this strength at least, cannot be recommended as a safe 

 summer spray for apple trees. 



"Atomic sulphur." The results secured with this material 

 were very satisfactory. No spray injury was observed on the 

 leaves and it will be seen on comparing plots 3 and 6 that the 

 condition of the fruit harvested from the plot sprayed with 

 "Atomic sulphur" was practically identical with that from the 

 standard dilution lime-sulphur plot. While these results were 

 in every way satisfactory one is not warranted drawing final 

 conclusions without farther comparative tests. It is admitted 

 that the relatively efficient scab control with this material may 

 be partly due to using it, through error, at double strength for 

 the first application, but attention is called to the fact ilieady 

 •pointed out that omitting an application of lime-sulphur at this 

 time produced practically no difference in the results. 



Arsenate of lead as a fungicide. In the above discussion 

 relative to the control of scab on the dififerent plots the action 

 of arsenate oif lead, which is added as an insecticide, has been 

 ignored as a factor in producing the effects obtained. More- 

 over, this appears to be the customary attitude in dealing with 

 experiments of this nature. The results secured on plots 

 sprayed with different amounts of arsenate of lead alone, dur- 

 ing the past two seasons, suggest that this is an erroneous posi- 

 tion to take. Not only that but one is strongly tempted to go 

 one step farther and say that there is reason to believe that so 



