128 REPORT OF THE BOTANIST OF THE 
disease must be spread by pickers while gathering the fruit; aiso 
in pruning and in cutting out the old canes; and particularly in 
the process of laying down and covering the canes with soil to 
protect them from winter injury. Cultivation, too, tends to 
spread the disease. 
The fungus can live on dead and decaying raspberry canes, 
and fragments of diseased canes lying on the ground are no doubt 
a prolific source of infection. How long the fungus can live on 
decaying material is not known. Another important point on 
which there is as yet very little accurate information is the rela- 
tion of the fungus to plants other than the raspberry. If it lives 
on a variety of other woody plants, as suggested by Saccardo 
(see page 114), such plants must serve to assist its dissemination. 
All of the evidence at hand tends to show that the fungus does 
— not travel any considerable distance except on infested plants. 
RELATION OF CANE BLIGHT TO THE DISCOLORED AREAS ON RED 
RASPBERRY CANES. 
During August and September the new canes of red raspberries 
often show brown or bluish-black areas one to four inches long 
and extending one-half to two-thirds or more of the way around 
the cane. (See Plate IX, Fig. 1.) These discolored areas are 
conspicuous and sharply defined. The discoloration is only in 
the bark and never extends to the sapwood. The cane is but 
slightly if at all constricted and, until the following spring, there 
is usually no evidence of any fungus in the fruiting stage. A 
single cane may bear from one to several such areas which may 
be located anywhere on the cane, but occur most commonly on 
the lower portion. These discolored areas are exceedingly com- 
mon on many varieties of red raspberries (Rubus strigosus and 
R. ideus) and have been found also on the purple variety Shaffer 
(R. neglectus), but have never been observed on any of the black 
varieties (Rk. occidentalis). The health of the affected canes does 
not seem to be impaired. 
At one time this discoloration was believed to be the early 
stage of cane blight,® but it has now been determined that they 
are due to an entirely different cause. 
5 See Bul. 191 of this Station, page 350. 
