446 
tection for various insects, especially the 
woolly aphis. 
7. If for any reason cankers are 
formed and are detected in the winter 
when very small, the development of the 
canker may be, in many cases, prevented 
by shaving off the thin outer layer of 
the bark. This will allow the cankers to 
dry out and will prevent, to a large 
extent at least, the formation of spores 
in the fall. This method would prob- 
ably be practical only on young trees, 
and, in any case, should be considered 
only supplementary to spraying. 
See Black Spot Canker of Apple. 
Bibliography 
1893-4. Washington State Board Horti- 
cultural Report, 1893-4, page 69. 
1900. Cordley, Oregon Experiment Sta- 
tion, Bulletin No. 60. 
1900. Cordley, Botanical 
page 48-f. 
1900. Peck, Torry Botanical Club, Bul- 
letin No. 57, page 21. 
1904. Lawrence Washington Experiment 
Station, Bulletin No. 66. 
Gazette. 30, 
1906. Cordley, Better Fruit, 1 and 5, 
November. 
1908. Cate, Oregon Countryman, 1 and 
2, 1 and 3. 
1912. Jackson, Phytopathology, 2 and 2, 
page 95. 
1912. Jackson, Oregon Experiment Sta- 
tion, Crop Pest Report, 1911-12. 
BacTeRiAL Pome Bricutr. See Blight 
under Pear. 
Bitter Roti 
Glomerella rufomaculans 
The apple bitter or ripe rot is the 
cause of some of the most extensive 
losses experienced by apple growers. It 
is due to a fungus which has been given 
a number of scientific names, the one 
by which it is now known being Glom- 
erella rufomaculans. The disease occurs 
throughout nearly all the country east 
of Kansas and Texas, and is especially 
destructive in a broad belt from Vir- 
ginia to Oklahoma. It is somewhat spas- 
modic in its occurrence and at times 
occasions almost total loss. It is stated 
that in four counties in Illinois in 1900 
the loss, due to this cause alone, amount- 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
ed to $1,500,000, and the estimated loss 
to the apple crop for the United States 
during the same year was $10,000,000 
The fungus lives on many different 
plants, causing a ripe rot of their fruits 
but is best known as causing the bitter 
rot of apples and the ripe rot of grapes 
The first signs of the bitter rot on the 
apple are to be seen in a slight light- 
brown discoloration under the skin of 
the fruit. The spots increase rapidly 
in size, maintaining a more or less cir. 
cular outline, and become darker brown 
in color. Soon the tissues underneath 
the spots soften and the area seems 
sunken. When the spots have attained 
a diameter of about half an inch, small 
black spots appear beneath the upper 
surface, through which they finally 
break, discharging pink masses of spores 
which are very sticky when moist. These 
black pustules are usually formed in 
rings, and as the spots increase in size 
a number of concentric rings may be 
seen. The brown coloration of the spots 
is an indication of the decayed condition 
of the tissues underneath, and there is 
usually a sharp dividing line between 
the sound and the diseased tissues. The 
fruit is seldom entirely destroyed ail- 
though it is rendered almost worthless. 
The tissues are at first hard, followed by 
the breaking down of the cells, and the 
partially decayed portions usually have 
a pronounced bitter flavor, from which 
is derived the name bitter rot. The 
fruits never become excessively soft and 
mushy, but often dry into what are 
called “mummy” fruits. 
It has been claimed that the fungus 
passes the winter in these fruits, spread- 
ing the infection the next season. While 
the spread of the fungus may be favored 
by the presence of the mummy fruits, 
yet a more important method has been 
found in the presence of cankers on the 
limbs of the trees. These are due to 
the same fungus as that occurring on 
the fruits, and their relation to the dis 
ease has been well established by Bur- 
rill and Blair, of the Illinois Station, 
and Von Schrenk and Spaulding, of the 
Bureau of Plant Industry. 
