36 BULLETIN 866, U. S. DEPARTMENT OF AGRICULTURE. 
as to cover the entire exposed cheek with a deep red blush, due to 
the coalescence of individual spots. This type of injury was com- 
mon in this locality, particularly in those orchards which had been 
thoroughly sprayed with Bordeaux. It was most severe on. the 
trees which had received the Pickering (A) spray, a little less 
severe on the trees treated with Pickering (C) spray, and very 
apparent on the Bordeaux-sprayed trees. The spotting or late 
Bordeaux injury, shown on all the sprayed trees, reduced the value 
of the 1917 crop. The unsprayed trees yielded the best fruit. The 
reduction of yield due to bitter rot was practically negligible. 
IN 1918. 
At the time of the third spraying, July 26, possibly 5 per cent of 
the leaves on the trees treated with the barium-water spray and some 
on the Pickering-sprayed trees and on the Bordeaux-sprayed trees 
showed a yellowing. The dry weather and heat during the previous 
four weeks may have been responsible for this yellowing which was 
not serious in any case. No injury to the apples was observed. At 
the time of picking no foliage injury of any consequence was observed 
on any of the plats. A brief outline of the theories advanced to 
explain the injury to f oliage which frequently results from the applica- 
tion of copper sprays is given on page 27. 
No results to show whether the sprays increased or decreased the 
yield are obtainable. The only available figures on yield are the 
records of the number of apples secured in connection with the 
bitter-rot counts, which are from but one tree of each plat. 
Summary. 
In 1916 practically all of the fruit from the trees treated with Pick- 
ering and Bordeaux sprays and from the check trees was infected 
with bitter rot, which made it impossible to determine the relative 
efficacy of the Pickering sprays. Slight injury to the leaves and 
fruit on the Pickering-sprayed trees was noticed. 
In 1917, Pickering (A) sprays containing 0.12, 0.25, and 0.5 per 
cent of copper sulphate injured apple leaves, and caused late Bor- 
deaux injury to the fruit. Pickering (C) sprays of the same strengths 
produced less injury. Standard Bordeaux. 4-4-50, spray, containing 
1 per cent of copper sulphate, also injured the leaves and russeted 
the fruit, although not as severely as the Pickering (C) spray. But 
little bitter rot was found on any of the Pickering- or Bordeaux- 
sprayed or check trees. Hence no control test of the sprays was 
obtained. 
In 1918 no injury to the leaves or fruit resulted from the use of a 
Pickering (C) spray containing 0.58 per cent of copper sulphate, 
