Seiridium cardinale cankers in a tolerant Cupressus sempervirens clone under naturally CO2‐enriched conditions

Ramets of the Cupressus sempervirens clone Bolgheri were raised in three CO₂ concentrations in a naturally CO₂‐enriched environment [360 (control), 680 and 1670 μmol mol^–1 CO₂]. Bolgheri is patented as resistant to Seiridium cardinale. The ramets were artificially inoculated using a virulent isolate of S. cardinale. Healing of the resulting cankers was visually assessed over 6 years. Six months after inoculation, cankers on trees grown at 680 μmol mol^–1 were significantly larger than the controls. However, no significant trend was recorded at later dates. In conclusion, the Bolgheri clone maintained its resistance to S. cardinale and could be used to control cypress canker even in increasing atmospheric CO₂ concentrations.