Biological characteristics of Diplodia sapinea f. sp. cupressi infecting Cupressus sempervirens L. in Tunisia

Cupressus sempervirens L. (Italian cypress), is a Mediterranean evergreen coniferous tree. Due to its ecological values, this cypress has been used in forest protection against desertification and soil conservation. Last decades, cypress dieback has been commonly observed in Tunisian forests. Symptoms of shoot dieback, necrosis, twig blight, and trunk cankers have been observed on cypress trees in Bou Chrik (Nabeul) region. The causal agent was identified as Diplodia pinea f. sp. cupressi. The mycelial growth rate of the fungus was evaluated by using four different media culture at 25 °C and at seven temperatures ranging from (5 °C to 35 °C) on PDA medium. The results showed that the species was able to grow in a range of temperatures ranging from 20 to 25 °C and showed a higher growth rate on PDA medium. A pathogenicity test was conducted on C. sempervirens seedlings, and the aggressiveness of the fungus was approved.