Spraying Experiments in Nebraska 
73 
are often distorted in shape. The growth of the cuticle is checked, 
while the inner tissues continue to grow. This causes the apple 
to become lopsided, and often causes cracking similar to that 
caused by scab and blotch. 
On the leaves, Bordeaux injury resembles to some extent the 
injury caused by some fungi. Brown spots of dead tissue 3 or 4 
mm. in diameter appear, at first regular, but as the spots increase 
in size and coalesce, becoming quite irregular. In cases of severe 
injury, these spots involve one-third to one-half of the area of the 
leaf, or more. Soon the remaining portions become yellow, then 
begin to wither and turn brown, until only the midrib and larger 
veins remain green; then these succumb and the leaves fall. 
Sometimes the leaves fall before turning brown. The number of 
leaves affected varies from a few, scattered over the tree, to almost 
all the leaves on the tree. 
Bordeaux injury usually does not occur for several days after 
the application and if no rain falls may not occur at all. However, 
as a rule, enough dew collects to cause some injury even in dry 
weather. On the foliage the injury was found to be more severe 
when the leaves had been injured by insects, hail, or other causes. 
This was also true of the fruit after a hailstorm at Florence. 
Lime used in excess does not prevent or lessen to any appre- 
ciable extent the injury from Bordeaux russeting. Neither is the 
application of milk of lime to the trees after Bordeaux has been 
applied of any appreciable benefit, as shown by table 47. 
Lime sulphur causes some injury to both fruit and foliage; but, 
unlike the injury caused by Bordeaux, it appears almost at once. 
It causes the most severe injury during hot dry weather. This is 
no doubt due to the oxidation of the tissues. 
On the fruit, lime sulphur injury, when not severe, resembles 
injury caused by Bordeaux, but in more severe cases the injured 
surface becomes hard and thickened. Unlike the netted appear- 
ance formed in Bordeaux injury, the surface is covered by more or 
less smooth and dark-colored scales, giving the fruit a scurfy ap- 
pearance. In the most severe cases, cracks appear on the injured 
surface, usually near the edges but often crisscrossing the entire 
surface. This injury is no doubt partly due to sun scald before or 
during the time when the oxidation of the tissues is taking place. 
That this must be the case is shown by the fact that the most 
severe injury is always found on the south and west sides of the 
trees. The injury before spraying or as it appears on unsprayed 
trees was much less severe and of a different appearance. Sun 
scald alone appears first as a brownish discolored spot with a fairly 
distinct margin. Later, in the most severe cases, the skin becomes 
sunken and remains smooth and dark. Very little cracking 
