PICKERING SPRAYS. 35 



IN 1917. 



On June 20 a severe hail storm injured the leaves. On June 21, 

 at the time of the second spray application, some burning of the 

 leaves on the trees treated with the Pickering sprays was noted, as 

 well as a slight burning of the leaves on the trees sprayed with Bor- 

 deaux, 4-4-50, 2-2-50, and 2-1-50. The burning caused by the 

 Pickering sprays was far more noticeable than that due to the Bor- 

 deaux sprays, and varied among the trees of the same plat. Little 

 difference was evident between the Pickering (A) and (C) sprays 

 with respect to caustic properties on this date. On August 2 the 

 leaves of the trees on plats A n A 2 , and B x showed the most injury. 

 Those sprayed with Bordeaux, 2-1-50, also showed severe burning 

 of the leaves. The trees in the upper portion of the orchard which 

 had been sprayed with standard Bordeaux spray showed marked 

 burning of the leaves, while those sprayed with the standard Bordeaux 

 in the lower part of the orchard showed but slight burning of the 

 leaves. 



Part of the Pickering-sprayed trees received only three applica- 

 tions, while the others were sprayed four times. The fourth applica- 

 tion of the Pickering sprays produced no additional injury. 



All the Pickering sprays reduced the yield of fruit, because of the 

 defoliation occurring during July and August. The fruit on the 18 

 trees receiving the Pickering sprays was under size. The jneld was 

 reduced to a greater extent on the trees sprayed with the Pickering 

 (A) sprays than on those sprayed with the Pickering (C) sprays. 

 Defoliation also caused a reduction in the yields of the Bordeaux- 

 sprayed trees and of those sprayed with Bordeaux, 2-2-50 and 

 2-1-50. Pickering (C) sprays produced about the same percentage 

 of defoliation as the Bordeaux sprays, while Pickering (A) sprays 

 caused much more defoliation. The figures in Table 10 do not show 

 any influence of the sprays on the percentage of apples that dropped 

 from the trees, which was very high on plats B 2 and B 3 . The A series 

 of sprays, which injured the leaves severely and caused the greatest 

 amount of spray injury, showed a low percentage of drops. The 

 number of drops (10 per cent) from the check trees and the lack of 

 increase of drops from the trees treated with the Pickering sprays 

 used on plats A t and B 1; the two strongest of each formula with respect 

 to percentage of copper sulphate, over those from the check trees 

 lead to the conclusion that the high percentage of drops for the 

 sprayed trees on plats B 2 and B 3 was not due to the sprays used. 



Spray or late Bordeaux injury of apples. — Early in September a 

 specking of the fruit on all the sprayed trees was noticed. This 

 injury, known as spray or late Bordeaux injury, consisted of red 

 spotting usually surrounding a lenticel, and generally found on the 

 exposed side of the apple. On some apples the injury was so severe 



