Bark Canker Disease of Apple Trees. Grace G. Gilchrist. 237 
Effect on colour 
Medium of medium 
f peptone agar — — 
ato glycerine agar — — 
jle juice — - 
rwort agar Slightly darkened 
ne juice — — 
hinsky’s solution — — 
Colour of Formation of 
mycelium mycelium 
White Centre of colony fibrous, edge 
smooth and forming a thin film 
on the surface 
Old portions brown, Practically all the growth is 
young portions white under the surface of the medium, 
in the form of a solid mass, No 
drops of liquid 
Orange Good growth, solidifying the 
liquid 
White Very large drops of light brown 
liquid 
Light brown Moderate growth 
White Poor growth 
In the above table it will be seen that grown on certain media 
the hyphae secrete yellowish and brown viscid drops. In view of 
the abundance of crystals of calcium oxalate in cultures of the 
fungus on agar media, this liquid was tested and found to contain 
oxalic acid. The variations of growth on different media are very 
great ; apple twigs, apple agar, and apple juice are very good media 
but the fungus prefers gelatine to agar. On no cultures were 
chlamydospores found and the colonies showed a marked absence 
of rings. The rates of growth are shown in the following graph: 
Rate of growth of Myxosporium corticolum on various media. 
c.ms. 
a 
| 
shies 
0 10 2 
oa nople Oar OO et eae 70 80 9O0days 
o————4 rune.agar.  o-- 
sISSaS © Potato glycerifte agar. °Beerwor t agar 
