Molecular identification and disease management of false smut disease (Graphiola phoenicis) on date palms grown in Türkiye

The date palm (Phoenix dactylifera L.) is a common ornamental tree in Turkey, frequently found in homes, hotels, and public gardens. This study aimed to molecularly identify Graphiola phoenicis, the causal agent of false smut in date palms grown in Turkey, and to determine the efficacy of fungicides in controlling the disease. Characteristic false smut symptoms were observed on date palms during 2020–2021 surveys in Adana. These included numerous cup-shaped black fruiting bodies (sori) that appeared on theauricles and the rachis of the fronds, releasing whitish filaments with powdery yellow spores. Molecular identification of the pathogen was carried out based on the internal transcribed spacer (ITS) region and the large subunit of ribosomal DNA (LSU rDNA). NCBI accession numbers assigned to the ITS sequences are PQ060144 and PQ060145, as well as PQ060146 for the LSU rDNA. Under field conditions, four fungicidal treatments—Boscalid (26.7%) + Pyraclostrobin (6.7%), Prothioconazole (175 g/L) + Trifloxystrobin (88 g/L), Copper oxychloride (700 g/L), and Tea tree oil (222.5 g/L)—were evaluated for disease control. In a two-year trial, a combination of Boscalid + Pyraclostrobin was the most effective, reducing disease incidence by 90.40% and 88.48% in consecutive years. This study not only provides the first molecular characterisation and confirms the presence of G. phoenicis in Türkiye but also proposes an effective fungicide strategy for its control in ornamental date palms.