Fungal diversity in chestnut galls induced by Dryocosmus kuriphilus from Basilicata Region (Southern Italy)

Abstract

In recent years, the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus has been reported to have a high incidence in Italy and other Mediterranean basin countries. In 2021-2022, a study was undertaken in the Basilicata Region (Southern Italy) to investigate the relationship between the galls produced by ACGW on sweet chestnut (Castanea sativa Mill.) and fungal pathogens. In particular, the fungal diversity from green and necrotic galls collected from two important sweet chestnut sites (Melfi and Rionero in Vulture) was investigated. Nineteen fungal taxa were identified based on their morphological and molecular traits. In both localities, the most frequent species isolated from green and necrotic galls were Gnomoniopsis castaneae, Colletotrichum acutatum, and Pestalotiopsis sp. It is essential to understand the role played by the galls as an inoculum source for sweet chestnut fungal pathogens, particularly for G. castaneae, an emerging pathogen of which biology is still poorly understood. Findings from the present study stressed that the complex relationship between host-insect-microbial community needs to be elucidated to be able to control the pathogenic fungi and consequently maintain sweet chestnut trees' health as they play a key role in the local agriculture (horticulture, forestry) and subsidiary economy