244 Report OF THE HorTICULTURAL DEPARTMENT OF THE 
A passing glance will enable one to distinguish between the 
two kinds of injury on fruit or foliage and they need never be 
confused if an examination be made of even their gross characters. 
INJURIES FROM FUNGI. 
Not infrequently the scab fungus of the apple and pear (Ven- 
turia inequalis (Cke.) Aderh.) causes russeting and malformation 
similar to that described as coming from bordeaux injury. Such 
russeting occurs very often on pears and even on the apple, when 
the scab spots are seemingly being thrown off by the healthy 
growth of the apple; one sometimes needs to make a critical 
examination to determine whether a russeted blotch is due to 
injury or to a fungus. F. C. Stewart, Botanist of this Station, 
tells me that there is an undetermined fungus which causes the 
russeting of the Kieffer pear in this locality and that its work, 
under some conditions, might easily be mistaken for bordeaux 
injury. 
Reference has already been made to the resemblance between 
bordeaux injury on leaves and the supposed work of certain 
fungi, as by species of Phyllosticta. Stewart and Eustace? found 
in the summer of 1902, that the spots caused by bordeaux injury 
were free from the pycnidia of Phyllosticta in early summer, 
July 10, but that later, August 28, the majority of the spots were 
inhabited by a species of Phyllosticta. These writers raise the 
question as to whether much of the so-called leaf-spot of the 
apple attributed to species of the above fungus may not be 
primarily due to bordeaux injury, the fungus being a saprophyte 
rather than a parasite. They say: 
“So far as known to the writers, the parasitism of the apple 
Phyllosticta has not been previously questioned. In the past the 
presence of the Phyllosticta pycnidia on circular, dead brown 
spots on apple leaves has been considered conclusive evidence 
that the spots were caused by the Phyllosticta, and the disease 
has been promptly diagnosed as leaf-spot. In the future the 
problem of determining the cause of such spots on apple leaves 
will be a more difficult one. It is our opinion that at least a 
large part of the so-called apple leaf-spot is due to spray injury 
and weather conditions and is not of fungus origin.” 
** Stewart and Eustace (58, p. 232). 
