254 Bush-Fruits 



longer plants are allowed to remain the more troublesome is the 

 disease likely to become. It is usually better, therefore, where it 

 is prevalent, to discard and remove plantations after three or four 

 good crops have been secured. 

 References. 



Geneva, N. Y., Expt. Sta. Bull. 124:261. 



Washington Expt. Sta. Bull. 97. 



Burkholder, Phytopathology, 4: 407. 



RASPBERRY CANE-BLIGHT 



Leptosphoeria coniothyrium, Sacc. 



Raspberry cane-blight is a disease which has caused much loss 

 among commercial raspberry-growers. Apparently it is widely dis- 

 tributed and is a serious enemy to combat. It attacks both red 

 raspberries and black-caps, though blackberries are apparently 

 exempt. It works chiefly on the fruiting canes, though young canes 

 are occasionally seen to be affected. The leaves suddenly wilt and 

 dry. Sometimes the whole cane may be affected, sometimes only 

 a single branch, more frequently only some part. With black-caps 

 the disease often starts from stubs left in pruning, gradually working 

 downward from branch to branch, sometimes on one side of the 

 cane only. Whenever the cane is encircled it dies. Sometimes there 

 may be several points of attack on the same cane. The bark where 

 attacked is usually lighter colored and smutty, with smoke-like 

 patches of spores. Sometimes minute pimples, the spore-cases of 

 the fungus, are visible. The diseased wood is much discolored and 

 very brittle. Sometimes, when a large part of the cane becomes 

 diseased before dying, the wood will crack and the bark peel off. 

 Canes may begin dying soon after the leaves appear in spring, but 

 the trouble increases as the season advances and becomes most 

 serious at ripening time. Canes loaded with ripening fruit may 

 suddenly wilt and dry up. The trouble does not seem to spread 

 from a single point of infection but diseased canes may be found 

 here and there all through a plantation. Thrifty plantations seem 

 to suffer as much as neglected ones. Apparently only the canes 



