ORCHARD SPRAYING EXPERIMENTS IN I912. 63 



times with standard dilution lime-sulphur and where the appli- 

 cations were made at the proper dates as was intended in the 

 original experiment. As will be seen later the results from this 

 block of trees furnished an excellent demonstration, when com- 

 pared with the other experimental plots, of the value of a fungi- 

 cidal spray for apple scab when applied just before the blossoms 

 open. This plot will be referred to as Plot G. 



Plots A to F inclusive were sprayed first on June 5 and again 

 on July I. Plot G was sprayed on May 24, June 5 and July i. 



Efeect of the Sprays on the Foliage. 



The experimental plots were under the constant observation 

 of the orchardist, Mr. Yeaton, and were frequently visited by 

 Dr. Lewis, the associate pathologist, and the writer during the 

 season. 



On June 5 there was no evidence of scab in any of the 

 orchards. On plot G where the first application of lime-sul- 

 phur was made on May 24 there was no evidence of spray 

 injury although an occasional leaf showed scorching at the mar- 

 gin. 



Plot A, 4 pounds of arsenate of lead with no fungicide, 

 showed a small am.ount of scab on the leaves of all of the trees, 

 some leaves being quite badly affected on the first of July. No 

 spray injury was noted at that time. By the middle of July 

 the scab had not developed much more but there was by this 

 time abundance of spray injury on the leaves. By August first 

 the foliage still plainly showed the effects of spray injury but 

 the evidences of scab on the leaves had largely disappeared. A 

 record was also kept on the appearance and development of 

 scab on the fruit on this and other plots but this will be dis- 

 cussed under another heading. 



Plot B, sprayed with 2 gallons of lime-sulphur and 2 pounds 

 of arsenate of lead diluted to 50 gallons, showed a quite general 

 infestation of scab on the leaves by July i. However, while 

 some of the leaves on all of the trees in this plot were attacked, 

 the infestation was, on the whole, recorded as slight as com- 

 pared with plots C. D. and E. By the middle of July there was 

 not much evidence of farther development of scab, but some 



