Molecular characterisation of Cytospora species in apricot orchards and management of the most virulent species through biological and chemical methods

Abstract Cytospora (Leucostoma) canker is a severe fungal disease affecting stone fruits, leading to yield loss and plant decline. This study aimed to identify Cytospora species in apricot orchards in Malatya province (Türkiye), assess their pathogenicity, and evaluate chemical and biological control methods. Fungal isolates from symptomatic apricot tissues were identified using ITS, TUB, and EF gene regions, revealing Leucostoma persoonii f. sp. persicae (1 isolate) and Cytospora leucostoma (11 isolates ) . Pathogenicity tests showed L. persoonii f. sp. persicae was the most virulent. Laboratory trials tested ten fungicides, with tebuconazole (99.11%), fluopyram + tebuconazole (99.03%), thiophanate-methyl (88.79%), and cyprodinil + fludioxonil (85.66%) showing the highest efficacy in inhibiting mycelial growth. In controlled field trials, fluopyram + tebuconazole (38.91%) was the most effective chemical fungicide before inoculation, followed by the biopesticides Bacillus subtilis (26.39%) and Trichoderma harzianum (29.93%). After inoculation, B. subtilis (16.19%) and T. harzianum (31.70%) were the most effective, and only tebuconazole (16.05%) was effective among the chemical pesticides. These findings highlight chemical and biological fungicides as promising control options for L. persoonii f. sp. persicae in apricot trees.