Hazelnut (Corylus avellana L.) is a major nut crop worldwide with increasing economic relevance in Spanish agro-industrial systems (Tous, 2005). A survey conducted in October 2024 in approximately 20 ha in Tarragona area revealed an incidence of 30% of trunk diseases (TDs). Plants belonging to the cultivars Daria, Negret, Pauetet, San Giovanni, Tombul, Tonda Giffoni showed branch dieback with internal discolored wedge-shaped cankers, reddish conidia masses and, in the severe cases, broken branches and plant death. In Spain, this symptomatology, known as “solcuit”, was associated with the fungal species Cytospora corylicola. Twenty symptomatic samples were sterilized in 1% sodium hypochlorite, rinsed twice in sterile distilled water, plated on PDA amended with streptomycin sulfate (PDA-S) and incubated at 25 °C for five days. Pure cultures obtained by hyphal-tip transfer were classified as Botryosphaeriaceae-like (20% isolation rate) and Diatrypaceae-like (75%), according to colony morphology (Zhang et al., 2021; Stoykov Stoykov Martino et al., 2024). ITS sequences of Diatrypaceae-like strains showed 100% identity with the strains IPV-FW349 of A. decipiens (DC.) Sacc. The sequences of Botryosphaeriaceae-like strains exhibited 100% identity for ITS, 99% for tef1 and tub2 with the ex-type strains CMW9081 of N. parvum (Pennycook Lolas et al., 2024). To our knowledge, this is the first report of A. decipiens and N. parvum causing hazelnut TDs in Spain where represent a serious threat to hazelnut production.
Piattino et al. (Sun,) studied this question.