486 
a a ee 
Fig. 1. Rust on Apple Foliage and Cedar Ap- 
ple. (New Hampshire Experiment Station.) 
effects produced is the so-called “cedar 
apples.” The fungus passes the winter on 
the Juniper and in the spring produces 
gelatinous outgrowths that contain numer- 
ous spores. These spores, when borne 
back to the apple foliage, produce the rust 
again, and thus the fungus passes from 
one host back to the other. 
Treatment 
Spraying has not usually been very 
effective in controlling the disease. Since 
the Junipers harbor the fungus through 
the winter the method of control is, obvi- 
ously, to destroy them. 
CHARLES BROOKS 
The Pacific Coast Cedar Rust of the 
Apple, Pear, Quince and Related 
Pome Fruits 
Gymnosporangium blasdaleanum 
For several years the writer has been 
studying a rust on several cultivated and 
native species of the pome family. In 
1908 the fruiting stage of this rust was 
found on the serviceberry, and on the 
thorn apple or haw. Later the same spe- 
cies was found on the apple, pear, quince 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
and the native pome fruits as noted be- 
low. 
The final stage of this rust is found on 
the incense cedar. 
During the past six years the writer 
has paid particular attention to this rust, 
for the reason that it is of considerable 
economic importance. While it occurs 
rather sparingly on all varieties of apples 
so far observed, it has been found to at- 
tack certain varieties of pears very seri- 
ously. The quince is also subject to con- 
siderable injury by this rust. 
In 1910 and again in 1912 serious in- 
fections of this rust were noted in some 
orchards in the Rogue River valley. In 
1912 the writer’s attention was called to 
a very serious infection in a small block 
of pears of the Winter Nelis variety 
which practically destroyed 95 per cent of 
the crop. The fruit was badly deformed 
and fully 50 per cent of the leaves were 
found infected. The attention of the 
writer was called to this orchard by P. E. 
Zepp, who brought specimens to the labo- 
ratory and who, under date of June 20, 
1912, wrote the following in answer to an 
inquiry made by the writer: 
“A block of 150 pear trees (mostly Win- 
ter Nelis) on the west side of the orchard 
was so badly diseased that the entire 
crop was lost. The fruits were covered 
with yellow spots and were all twisted 
out of shape. Later, these fruits dropped 
off. The foliage was also badly injured 
and it was hard to find a leaf that was 
not attacked. There were other varieties 
in the orchard that also had rust on them. 
Even Kieffer pears were attacked, but the 
Winter Nelis was most hurt.” 
All varieties of pears are not equally 
susceptible, but both European and Ori- 
ental varieties were found affected. Ori- 
ental hybrids, such as the Kieffer, showed 
infection in a more or less serious degree. 
The incense cedar, which bears the resting 
stage, is very common in Southern Ore- 
gon, being found on the floor of the Rogue 
River valley and on the dry hillsides. The 
rust was not noted as affecting the cul- 
tivated pome fruits until the orchards 
were pushed into the foothills in the 
