I 
16 
Colorado Experiment Station. 
DISEASES.* 
Raspberries in Colorado are not troubled with many fungus dis¬ 
eases, for the reason that the climate is too dry for the spread of such 
troubles as affect the canes above ground. 
Anthracnose. 
This can be detected by gray discolored spots found on the canes 
above ground. When these spots become very numerous they may 
cause death or greatly weaken the plant. The disease is a surface one, 
namely, it lives on and in the bark. 
Treatment .—Affected old wood should be removed and burned 
as soon as the fruiting season is over. In setting out new plantations 
careful inspection of the plants should be made to avoid any with dis¬ 
eased canes. Spraying may be done with one-half strength Bordeaux 
or self-boiled lime sulfur. In this case it must be remembered that the 
mycelium lives over winter in the canes, and that spraying can only 
prevent the germination of spores as they are produced. Black rasp¬ 
berries are perhaps more susceptible to the trouble than the red 
varieties. 
Orange Rust. 
This disease is detected by the orange-red color on the under side 
of the leaves. This discoloration is due to the abundance of sori, 
which produce the orange-red spores by means of which the disease is 
spread from plant to plant. The mycelium of the fungus which corre¬ 
sponds to the roots of higher plants lives through the winter on the 
canes and roots of the raspberry. For this reason spraying is not very 
beneficial for its control. This disease is found more often on black¬ 
berries than on raspberries. Black raspberries are more susceptible to 
it than the red varieties. 
Treatment .—All diseased plants as soon as discovered should be 
dug up and burned. 
Crown Gall. 
This disease, caused by bacteria, is characterized by a rough knotty 
growth around the base or on the roots of the plant. 
The most satisfactory treatment for this trouble is to avoid plant¬ 
ing any diseased stock. When found in the plantation take out dis¬ 
eased plants and destroy. 
Cane Blight. 
This disease has been thought for many years to have been winter 
injury. It is now thought to be a fungus trouble and is being worked 
on by Prof. W. G. Sackett of this station. 
*The accounts of these diseases are taken l.argely from Card’s “Bush 
Fruits.” 
