RASPBERRY DISEASES 419 
normal. The lesions become whitish at the center in Sep- 
tember and October. Later small black pustules develop. 
Cause. 
The fungus Mycospherella Rubina causes spur-blight. Its 
mycelium invades the cortex, wood and pith. Within two weeks 
after the fungus falls on the spur a typical lesion is produced. 
The fungus apparently hibernates as immature perithecia in 
the canes. In the spring these bodies mature their ascospores. 
This occurs about the first of May. These spores are liberated 
and are carried by the wind to young canes which are at this 
time but a few inches high. 
Control. 
It has been demonstrated in Colorado that spraying will 
prevent spur-blight. The time of inoculation necessitates that 
spraving be done early in the spring. Bordeaux mixture 3-2-50, 
with the addition of resin-fish-oil-soap at the rate of two pounds 
to fifty gallons of bordeaux as a sticker, is advised. Apply to 
the young canes only, and care should be taken to coat the por- 
tion nearer the ground. Four applications are advised; three 
before picking at intervals of two weeks and one immediately 
after picking. The first application should be made when the 
plants are only a few (eight to twelve) inches high. This is the 
last of May in Colorado. The second spraying follows two 
weeks later. The third two weeks after the second. Old 
fruiting canes should be removed and burned immediately 
after harvest to prevent infection of new canes. 
REFERENCES 
Sackett, W. G. Spur blight of the red raspberry caused by Spherella 
rubina. Colorado Agr. Exp. Sta. Bul. 206: 3-26. 1915. 
Robbins, W. W., and Reinking, O. A. Fungous diseases of Colorado 
crop plants. Raspberry. Spur blight. Colorado Agr. Exp. 
Sta. Bul. 212:45. 1915. - 
Stewart, F. C., and Eustace, H. J. Raspberry cane blight and rasp- 
berry yellows. Relation of cane blight to the discolored areas 
on red raspberry canes. New York (Geneva) Agr. Exp. Sta. Bul. 
226 : 354-358. 1902. 
