A twig canker on Russian olive caused by Phomopsis arnoldiae in Italy.

From the necrotic margin of irregularly shaped cankers on stems and twigs of Russian olive (Eleagnus angustifolia L.) grown in central Italy, Coniothyrium fuckelii Sacc., Penicillium spp., and Phomopsis arnoldiae B. Sutton were isolated. Artificial inoculations were made on stem of 3-year-old, container-grown E. angustifolia seedlings using two isolates each of the three fungi, previously grown on PDA. Controls were treated in the same way but with sterile disks of PDA. Each treatment was replicated with 10 seedlings and incubated in the greenhouse (20 ± 2°C, 80% relative humidity, and 12 h of natural light per day). After 30 days, wounds treated with P. arnoldiae showed necrotic lesions that developed into small patches of dead bark that cracked forming cankers. Radial sections through the stem at the canker site showed the presence of mycelium in the vessels, from which P. arnoldiae was reisolated. No disease symptoms or mycelium in the inner tissues were observed in the control plants or in the plants inoculated with the other fungi. The pathogenicity test was repeated twice with the same results. To our knowledge, this is the first report of this disease in Italy.