86 PEACH LEAF CURL: ITS NATURE AND TREATMENT. 



average amount of healthy foliage of the control trees. The fifth sub- 

 ject, thriftiness of leaves, is discussed in the next general head of this 

 chapter. 



In considering the saving of foliage induced through the use of the 

 sulphur, lime, and salt sprays (rows 1, 3, and 6) in comparison with 

 the average saving of sprays containing an equal amount of sulphur 

 but no salt (rows 7, 9, 10, 16, 57, 12, and 51), there appears to be a 

 slight gain in favor of the former sprays. The average saving from 

 both classes, taken together or separately, is in proportion to the 

 amount of sulphur contained in the spray. With 15 pounds of sul- 

 phur the average net gain in healthy foliage was 580 per cent; with 

 10 pounds, 547 per cent; with 6 pounds, 528 per cent; and with 5 

 pounds, 480 per cent. 



In considering the combined sulphur and copper sprays (rows 18, 

 19, and 36), it is well to omit comparisons of row 36, on account of 

 the injury caused to the effectiveness of the spray applied to it through 

 the precipitation of a portion of the sulphur in boiling, as has already 

 been noted. Rows 18 and 19, containing 3 pounds and 2 pounds of 

 copper sulphate, respectively, and each containing 5 pounds of sulphur 

 and 10 pounds of lime, show a gain in healthy foliage of 549 per cent 

 and 537 per cent, or an average gain of 543 per cent. The average 

 gain from the sulphur sprays, which contained the same amount of 

 sulphur but no copper, was, as already stated, 480 per cent. This 

 shows the advantage of adding the copper to the sulphur sprays. 



In the table the experiments with the Bordeaux mixture are 

 arranged according to the amount of copper and lime used in each. 

 The results obtained in the 9 experiments bring out some valuable 

 facts respecting the most desirable proportions of copper and lime to 

 be used. Of the 9 experiments with Bordeaux mixture, 2 formulae 

 contained 15 pounds of lime each, 3 formuL-e 10 pounds each, and 4 

 formida? 5 pounds each. 



By comparing rows 15 (6 pounds copper sulphate, 15 pounds lime), 

 41 (5 pounds copper sulphate, 10 pounds lime), and 21 (5 pounds cop- 

 per sulphate, 5 pounds lime), it will be seen that there was a gain in 

 healthy foliage of 589 per cent, 566 per cent, and 634 per cent, respec- 

 •tively. Dividing these gains by the number of pounds of copper in 

 the respective formulae, which may be fairly done, owing to the nearly 

 equal amounts of copper contained in each, the following results will 

 be obtained: 



Per cent. 

 Row 15 (6 pounds copper sulphate, 15 pounds lime = l pound copper to 2.5 



pounds lime) shows a gain of foliage per pound of copper sulphate of 98 



Row 41 (5 pounds copper sulphate, 10 pounds lime = 1 pound copper to 2 



pounds lime) shows a gain of foliage per pound of copper sulphate of 113 



Row 21 (5 pounds copper sulphate, 5 pounds lime = 1 pound copper to 1 pound 



lime) shows a gain of foliage per pound of copper sulphate of 127 



