Archivio Journal of Plant Pathology

Abstract:

Slow decline was observed in five mature and unmanaged hazelnut orchards in central Italy. Trees were trained into multi-branch bushes, and declining trees showed sparse crowns with chlorotic leaves and dead branches. Severely damaged trees died. Dead and declining branches were affected by a yellowish wood decay, especially at the base. Resupinate fruiting bodies, typical of Fomitiporia mediterranea or F. punctata, were observed on the dead branches. Vegetative Fomitiporialike isolates were also obtained from the decayed wood of declining/living branches. Thirty four fungal isolates, either derived from the fruiting bodies or the vegetative isolates, were identified as F. mediterranea by ITS sequencing, specific primer-based PCRs and RFLP. A reliable PCR-based detection method from decayed wood was developed. Based on the presence of fruiting bodies, the incidence of the fungus was 18% and 14% in orchards 1 and 4, respectively. However, based on F. mediterranea detection by PCR from decayed wood samples (26 trees), the incidence was 100% in orchard 1 and 99% in orchard 4. F. mediterranea was also found on wild hazelnut growing in forests located in the same area as the hazelnut orchards. Furthermore, the hymenomycetes Coniophora puteana, a known agent of wood decay, was found in the decayed wood of one declining tree. This is the first time F. mediterranea and C. puteana have been reported on hazelnut.