Botryosphaeria Canker is a stress related disease caused by the fungus Botryosphaeria. It will infect numerous hosts that have been stressed by various factors such as poorly drained soils, freeze damage, mulch layer too thick or the planted too deeply. Usually stem cankers and splitting of the bark are present. The fungus attacks the cambial layer, disrupting the flow of nutrients and water which results in the death of the upper areas of the plant which leads to the decline of the root system. If the soil is excessively wet then root rot may be a problem with Phytopthora being active. There is no cure for this disease other than removal 
of infected tissue if possible and fertilization to help the tree initiate new growth. The best remedy is to select trees and shrubs disease free and then plant them correctly.
Copyright 2012 Patrick G. Mawhinney Photo below courtesy of Pete Hester 2102 Use with permission only
