144 



MASS. EXPERIMENT STATION BULLETIN 254 



pink dust (May 14) the basic sulfates and copper-lime dust seemed to give similar 

 results with very little burning. In the calyx dust (May 24) none of the dusts was 

 effective in controlling scab. The dusts were applied in the morning when there 

 was very little wind but did not adhere as well as expected (Cutler). Doran made 

 the following observations as to injury and scab on foliage: 



Table 14. Relative Eflfectiveness of Low and High Basic Sulfate Dusts, Copper-lime 



Dust, and Lime-sulfur Spray in Controlling Scab, and 



Amount of Injury,— As Shown by the Foliage 



Plot Fungicide June 14 July 16 



Check No burning Not much leaf burn. 



Scab very severe. Scab most severe. 



1 Low basic sulfate No burning. Not much leaf burn. 



More scab than with lime-sulfur. Scab very severe. 



2 Lime-sulfur No burning. Not much leaf burn. 



Scab moderate. Less scab than with dusts. 



3 High basic sulfate No burning. Moderate leaf burn. 



Scab severe on Mcintosh. Scab very severe. 



4 Lime-sulfur No burning. Not much leaf burn. 



Much less scab than with dusts. Scab bad. 



5 Copper-lime dust No burning. Not much leaf burn. 



More scab than with lime-sulfur. Scab severe. 



6 Lime-sulfur No burning. Not much leaf burn. 



Considerable scab on Mcintosh. Less scab than with dusts. 



As a whole Doran noted comparatively little injury to apple foliage from either 

 copper dusts or lime-sulfur spray. The high basic sulfate may have been slightly 

 the most injurious. None of the treatments afforded adequate protection to the 

 foliage against scab probably because of too late application and adverse weather 

 conditions. The best control was obtained with lime-sulfur although inconsistent 

 and "bad" on plot 4. Scab was severe or very severe with all dusts and most 

 severe on the check trees. A closer differentiation would require leaf counts which 

 was not attempted. The effect of insects was negligible (Bourne). .As all the 

 plots did not receive the same fertilizer treatment the yields were not comparable 

 and are omitted. 



Doran and Bourne made fruit counts on 1825 Mcintosh apples from the several 

 plots on October S and obtained the following results : 



Table 15. Relative Effectiveness of Low and High Basic Sulfate Dusr.s, Copper-lime 

 Dust, and Lime-sulfur Spray in Controlling Scab on Mcintosh, 

 and Amount of Injury, — As Shown by Fruit Counts 



Plot 



1 

 3 

 5 

 2, 4, 6 

 



Fungicide 



Clean 



Per cent 

 Low basic sulfate 2.50 



High ba=ic sulfate 7.84 



Copper-lime dust 14.44 



Lime-sulfur 27.66 



Check ■ • • • 



Scab 



Russet 



None of the fungicides gave control of scab on Mcintosh apples because of too 

 late application (Shaw). From the standpoint of scab control and a minimum of 

 russet injury, lime-sulfur spray was rather more effective than the copper dusts. 



