Floricane tips or whole canes are grey/silver in appearance
Cane blight. Cane blight can be a devastating disease in blackberry. The canes are infected when they are tipped or pruned as primocanes, the wound becomes infected and the disease will continue to grow down the cane, sometimes causing loss of the entire cane.
Both Primocanes and Floricanes are Wilting
Canes with galls. Larva of rednecked cane borers feed inside primocanes creates a gall and girdles the canes. Infested canes either die or become weakend so they cannot growth in the following year when they are floricanes. Adults feed on leaves.
Floricanes Are Wilting
Winter injury damages floricanes. Buds appear healthy and start to grow, then suddenly wilt. Damage likely occured in the spring when the plants started to deacclimate and then were exposed to sudden abnormally cold temperatures.
Crown borers cause individual canes to wither and die when fruit is developing, or canes start to lodge and can be easily pulled from the plant.
Rodents can chew off bark at the base of floricanes in the winter, girdling them.
Primocanes Are Wilting
Pseudomonas is a relatively new disease to blackberry and often occurs later in the summer after a period of wet weather. ‘Arapaho’ most often shows these symptoms.