What is your diagnosis?

摘要

Sudden mortality of horse chestnut trees (Aesculus hippocastanum) has been observed in northern France and near Brussels, Belgium, since 2001. The symptoms include rapid decline characterized by cessation of growth, less abundant foliage, yellowing of foliar branches and complete defoliation. Cortical fissures are sometimes also present and subcortical necrosis is observed in felled trees. Urban trees are often affected. Hypotheses are outlined which explain this phenomenon and it is suggested that Phytophthora may be the causal organism.