36 BULLETIN S66, U. S. DEPARTMENT OF AGRICTJLTTTRE. 



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 foliage 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 eopper 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 0.5S per cent of copper sulphate, 



