Raspberry Cane-blight 255 



are affected, neither the roots nor the leaves being attacked. A 

 diseased cane is shown at Plate VIII. 



In many plantations the loss may not be very serious, yet at times 

 it has taken one-fourth to one-half the crop. As a rule it is more 

 destructive hi older plantations, becoming more and more serious 

 as the plants grow older. Yet the damage varies from season to 

 season, and a plantation seriously affected one year may sometimes 

 suffer less the next. Damp weather during the period of infection 

 doubtless favors its spread, but later weather conditions probably 

 have little influence. The fungus is supposed to gain entrance to 

 the young canes during summer and autumn, perhaps also the 

 following spring, when they have become fruiting canes. 



Infection commonly takes place in wounds of various kinds. In 

 black-caps it often starts where the young cane has been pinched 

 back; also wherever branches have been removed, rubbed or split. 

 The wounds of the tree-cricket are a common point of attack. 



All varieties are affected but some more seriously than others. 

 Cuthbert and Marlboro, two of the leading commercial red rasp- 

 berries, seem to be particularly susceptible. Columbian, on the 

 other hand, is comparatively exempt. 



Methods of control j No definite methods of fighting this trouble 

 appear to be available. Spraying does not seem to have given 

 results of much promise. The disease is readily carried in young 

 plants, hence the first precaution is to secure healthy stock if possi- 

 ble. This, in turn, should be planted on uninfected soil, where 

 raspberries have not been previously grown. Removing and burn- 

 ing the old canes as soon as fruiting is over is a wise precaution, 

 since it is upon these old canes that the spores are being ripened. 

 In setting young plants, as little of the old cane as possible should 

 be left if there is reason to suspect that they carry any of the disease. 

 This fungus is probably largely responsible for the fact that rasp- 

 berry plantations must be so frequently renewed in order to pro- 

 duce profitable crops. 

 Reference. 



Geneva, N. Y., Expt. Sta. Bull. 226. 



