The affliction begins with small spots and then evolves into large brown patches. The older leaves were the first to suffer and the condition has progressed rapidly onto the new leaves.
Some of the leaves have browned completely and the stem is beginning to shrivel. I don’t believe this particular stem will be recovering. I would hate for this to be the fate of the entire bush.
Deerberry is closely related to the blueberry and I imagine is susceptible to many of the same diseases. These symptoms are similar to those seen on blueberries suffering from various fungal infections. The plants may be infected by more than one type of fungus.
Whole populations of Deerberry are feeling the effects of the blight. I’ve mentioned the above average rainfall we’ve had here and the resulting increased plant growth. Another thing that thrives in warm, wet conditions is fungi. Shrubs growing in these dry open areas are seldom exposed to extremely wet conditions. I think the plant infecting fungi have just had perfect growing conditions this summer and the Deerberry is suffering as a result.
These shrubs have suffered die-backs before and have always recovered. Extreme winter temperatures and severe drought conditions have both caused the death of most of the branches, but the plant has always recovered by resprouting from a healthy root system. I only hope we don’t have one of the root attacking fungi settle into these plants.