New York AGRICULTURAL EXPERIMENT STATION. 265 
Green* believes that the russeting on the fruit comes with late 
spraying. He cautions against using bordeaux mixture more 
than twice after blooming, since, “ when applied too late in the 
season it sometimes causes a russet appearance of the apple.” 
But from the study of the matter at this Station it does not 
seem probable that bordeaux injury occurs on apples after the 
hairs have been shed, the stomata changed into lenticels, and the 
waxy coating formed. This period of immunity begins with 
Baldwins and Rhode Island Greenings in from four to six weeks 
after blossoms drop. It may be assumed that the time for these 
changes must vary greatly with the season and possibly with 
the variety. Unfortunately these early weeks cover the period 
when we must spray for the scab fungus — the immunity which 
apparently comes with age is too late in the season to take 
advantage of in spraying operations. 
Development of bordeaux injury on leaves Unfortunately for 
these experiments there was so little bordeaux injury of the 
foliage in our experimental plats that it is not possible to give 
as clear a statement of its development on the foliage as one 
would like. It is certain, too, that such observations as were 
made would, for most part, be modified more or less by varying 
weather conditions and on other varieties than the two in these 
experiments. ; : 
The injury develops less quickly on foliage than on fruits. It 
first shows as dead brown spots of various shapes and sizes 
though usually of irregular outline. These spots begin to ap- 
pear as did the injury on the fruit, immediately after the first 
rain following the application of the bordeaux mixture, but 
in comparison with the injury on the fruit the development of 
the characteristic spots was slow and two weeks intervened be- 
tween the first indication of the injury and the full formation of 
the dead brown spots; it was almost two weeks later before the 
leaves took on the yellow color, accompanied with falling, this 
being at its height July 6, too late for the injured leaves to be 
replaced by new ones. 
In a few cases the dead spots fell out, but in no great number 
of leaves did this occur. There was none of the “shot-hole” 
effect which Bain® describes on peaches, and Muth®® on grapes. 
The separation of dead from living tissues in the leaves of 
Green (26, 9:13). 
* Bain (4, pp. 69-73). “Muth (46, p. 2). 
