Plant Pathology Science

Hazelnut tree has natural habitats in northwestern Iran in the forests of Ardabil and Gilan provinces. Decline disease is a threatening agent of hazelnut trees in these areas. Symptoms of the disease include weakness, reduced growth, leaf fall and dieback of the branches, branch and trunk canker and root rot that eventually lead to the gradual death or decline of the tree. In Iran the fungi cause hazelnut decline disease, Diaporthe amygdali, and Cytospora fuckelii as canker and Fusarium semitectum, F. lateritium, F. anthophilum and Armillaria mellea as root rot causative agents. This article describes symptoms of hazelnut decline in Iran, pathogenic fungi and management strategies.