New YorkK AGRICULTURAL EXPERIMENT STATION. 193 
Plate XXV, Fig. 1.) Specimens of this peach knot were sub- 
mitted to Mr. A. D. Selby, botanist of the Ohio Experiment Sta- 
- ton, who identified them as being the same as the “ twig disease 
with gum flow” discussed by him in Ohio Experiment Station 
Bulletin 92, pages 199-206. The knots are almost invariably 
covered with gum. In midwinter we examined many of these 
knots collected in different localities and nearly always found 
spores of Helminthosporium (apparently H. carpophilum) in the 
gum. Sometimes the spores were abundant. 
Hyphe are not abundant in the tissues of the knots. In fact, 
it is not clear that they contain any hyphe except occasionally 
those of saprophytes. 
A pure culture of the Helminthosporium on the knots was ob- 
tained and peach twigs inoculated with it. The inoculated 
twigs became much blackened at the point of inoculation and 
there was a copious exudation of gum, while on the check twigs . 
there was no blackening and very little gum. Although the fun- 
gus seemed to be parasitic the twigs manifested no tendency to 
form knots. 
In the latter part of the season we occasionally found peach 
twigs which were killed by the same Helminthosporium. In such 
cases the twig was strangled at a point from 6 to 12 inches back 
of the tip. At the point of attack the bark was of a gray color 
and Helminthosporium spores were plentiful, but there was no 
enlargement of the twig. ; 
We have also sought for Helminthosporium on peach leaves, 
but without success except in one instance. In the Station 
orchard some peach trees, the fruit of which was infested by . 
| Helminthosporium, showed considerable shot-hole injury on the | 
leaves. An examination of the affected leaves was made Sep- 
tember 4. Most of the spots had fallen out, but on those re- 
maining we occasionally found Helminthosporiwm spores iden- 
ium the germination is often of a peculiar sort. (See Plate XX, Fig. 7.) 
The average dimensions of 17 spores grown on sugar beet agar was 
1372x385 y. As found in nature on the fruit and branches they are some- 
what smaller, 
13 
