Blackberry Diagnostic Tool

Canes Exhibit Abnormal or Stunted Growth

Lack of cane development in spring (go to virus section)

Double blossom or rosette of blackberry is caused by the fungus Cercosporella rubi. Infected buds give rise to multiple shoots. Fruit usually do not develop on infected canes. Some buds develop normally while others are have multiple shoots with short internodes. The photo on the right shows the multiple shoots and short internodes.

Bud growth is stunted and pink/white not green (photo on left). Buds on floricanes will either not develop or will be stunted. New primocanes are distorted and abnormally colored (photo on right). These symptoms are caused by glyphosphate.

Canes have 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.